• The Korean Journal of Nuclear Medicine
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• v.34 no.4
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• pp.276-284
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• 2000

Purpose: We investigated the operative outcome after bypass surgery in patients selected using viability criteria on F-18 FDG PET. Materials and Methods: Rest-24hr delay redistribution imaging of Tl-201 SPECT and F-18 FDG PET were performed in 11 patients. Seven of these 11 patients (6 men, 1 woman) were evaluated to have viable myocardium by F-18 FDG PET. Changes in symptoms and left ventricular ejection fraction (LVEF) after operation were evaluated. Results: In seven of 11 patients, a significant amount of viable myocardium was found on F-18 FDG PET and Tl-201 SPECT. Severity of both chest pain and dyspnea improved markedly in all patients. Mean LVEF improved from 22% to 32%. Conclusion: F-18 FDG PET could be used to select the patients who will benefit from coronary artery bypass surgery.

• The Korean Journal of Nuclear Medicine
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• v.31 no.1
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• pp.43-49
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• 1997

We studied to investigate the predictive values of gated SPECT for the improvement of wall motion after bypass surgery. As we compared postoperative SPECT with preoperative ones, we defined viability as wall motion improvement. We peformed rest T1-201/s1ress Tc-99m-MIBI gated SPECT in 25 patients before and 3 months after bypass surgery. Myocardial wall motion was graded as normal, hypokinesia, akinesia, and dyskinesia by pair-wise visual analysis of gated pre and postoperative SPECT's on the same monitor screen. Myocardial wall thickening was determined good or poor Among 92 segments with wall motion abnormalities before operation, 69 (75%) improved and 23 did not. Before operation, we could find segments with good systolic thickening in 64 segments among total 92. Thickening of the remaining 28 was poor. Wall motion improved postoperatively in 45 segments (70%) among 64 with good thickening. Twenty four(86%) among 28 segments with poor thickening had also improved. We grouped segments into mild(hypokinetic) and severe(akinetic/dyskinetic) ones. Among 33 segments with severe motion abnormalities, 14 had good thickening and 19 did not. Nine(60%) improved out of 14 segments having severe abnormality with good thickening However, 16(84%) segments out of 19 haying severe abnormality with poor thickening also improved. Neither degree of perfusion decrease nor severity of wall motion abnormalities could explain the high rate of false negatives. In conclusion, as we defined viability as wall motion improvement by comparing pre and postoperative SPECT, systolic thickening observed by gated Tc-99m-MIBI SPECT in myocardial segments with wall motion abnormalities predicted wall motion improvement after bypass surgery. However, poor thickening could not be referred as evidence of nonviable myocardium both in mild and severe contractile dysfunction, so that we might need stimulation study such as dobutamine echocardiography or dobutamine gated SPECT.

• Proceedings of the Korean System Dynamics Society
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• 2004.08a
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• pp.87-107
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• 2004

우리나라에 이동통신이 처음 소개된 이래로 눈부신 발전을 거듭하여 왔으며, 급기야. 무선통신 서비스를 중심으로 새로운 성장력과 패러다임 전환의 가능성에 대한 전망을 논할 수 있는 수준이 되었다. 이러한 추세에 맞추어 휴대인터넷 시장에 대한 연구가 활발히 진행되고 있으며 국민경제적 효과변화나 시장 경쟁환경의 변화에 가장 영향을 미칠 수 있는 요인들 중, 사업자 수를 어떻게 선정할 것인가에 대해 다양한 접근이 시도되고 있다. 기존의 연구들은 휴대인터넷 시장을 분석하는데 있어 시장규모가 일방향으로 사업자 수에 영향을 미친다는 측면에서 이루어지고 있으며, 대부분 휴대인터넷 시장을 단일시장으로 범위를 한정하고 성장중인 시장을 정적으로 가정하여 시장성장 추이 분석 등에 주안점을 두는 단편적 연구가 수행되어져 왔다. 휴대인터넷 시장의 단편적 분석이 아닌 '모바일인터넷' , '초고속유선인터넷', '무선인터넷', '휴대인터넷' 등 네 가지 영역을 동시에 고려함으로써 영역간 복잡성과 동적인 관계 속에서 시장이 성장해 나아간다는 가정을 바탕으로, 시장에 내재되어 있는 관련요소간 상호영향과 신규정책 및 제도적 변화 수용에 있어 발생하는 시간적 공간적 지연 등을 고려한 동태적 분석을 수행하였다. 연구를 수행하기 위해 다양한 변수간의 인과관계, 피드백 구조와 시간흐름에 따른 시스템의 변화를 파악하는데 매우 유용한 도구인 시스템다이내믹스 기법을 활용하여 휴대 인터넷 시장의 동적인 구조를 알아보고 사업자 선정정책의 시행을 앞두고 있는 현재시점에서 의미있는 시사점을 제공하였다.시하고자 한다.채취하여 임신진단키트(제네디아프로테 트, 녹십자)를 이용하여 임신여부를 1차적으로 확인하였다. 과배란을 유기한 13두의 공란우중 9두(69.2%)가 과배란 반응을 나타내었으며, 회수된 수정란 51개중 이식가능수정란은 38개(74.5%) 였다. 발정동기화를 유도한 수란우 40두중에서 35두(87.5%)가 발정이 동기화되었으며, 그 중 황체검사를 통하여 30두의 수란우에 수정란을 이식하였다. 수정란이식후 13일(발정주기 21일)에 혈액을 이용한 임신진단에서 농가별 수태율은 각각 37.5%, 70.0%, 60.0% 및 71.4% 로서 평균 60.0%를 나타내었다.서 39$^{\circ}C$, 5% $CO_2$ 배양기에 48시간 배양하면서 생존여부를 판단하였다. 실험 2에서 확장배반포배 수정란이 25.3%의 생존율을 나타내었으며, 실험 1과 실험 3에서는 수정란의 형태와 관계없이 생존성을 확인할 수 없었다. 이상의 결과로 보아 glycerol 완만동결에서는 확장배반포기 수정란 이상이 보존가능한 것으로 추정되나 더 추가적인 연구가 요구된다.c kinase 활성의 변동은 정소 내 간충조직, 세정관 상피의 증식 및 기능적 분화 과정을 매개하는 생리적 활성분자 수용체 하위의 신호전달 과정에 Src-Csk loop에 의한 조절가능성을 확인할 수 있었다.rugrene의 향기성분이 주요 성분군으로 확인되었다. 2. 생강나무에서 생강의 향기를 발산하는 성분으로는 $\beta$-myrcene, o-terpinolene, phellandrone, ι-limonene, $\b

• Tuberculosis and Respiratory Diseases
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• v.47 no.3
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• pp.339-346
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• 1999

Background : Non-small cell lung carcinoma is a common tumor with a poor prognosis. Of all malignancies, it is the main cause of death for male and female patients in the Western world. Resection remains the most effective treatment when feasible. Accurate description and classification of the extent of cancer growth are important in planning treatment, estimating prognosis, evaluating end results of therapy, and exchanging information on human cancer research. Until effective systemic therapy is available for non-small cell lung cancer, development of new treatment strategies depends on knowledge of the end results achieved for carefully staged groups of patients in the lung cancer populations. For these reasons, we investigated the survival rate in radically resected non-small cell lung cancer patients by newly revised staging system adopted by the American Joint Committee on Cancer and the Union Internationale Contre le Cancer. Methods: Clinical, surgical-pathologic and follow-up informations on 84 consecutive, previously untreated, patients who received their primary treatment for non-small cell lung cancer were investigated. Staging definitions for the T(primary tumor), N(reginal lymph node), and M(distant metastasis) components were according to the International Staging System for Lung Cancer. Death from any causes was the primary target of the evaluation. Results: The median survival rates were as follows; stage I ;79.1 months, stage II ;47.3 months, stage IIIa; 22.7 months, stage IIIb; 16.1 months, and stage IV;15.2 months versus newly revised stage Ia;58.5 months, stage I b;76.0 months, stage IIa; not available, stage IIb;43.0 months, stage IIIa;22.5 months, stage IIIb; 16.1 months, and stage IV;15.2 months. The survival rates were not significantly different between old and newly revised staging system. Cumulative percent survival at 36months after treatment was 100% in stage Ia, 80% in stage Ib, not available in stage IIa, 26 % in stage IIb, and 21 % in stage m a respectively. Conclusions: Although these data were not significantly different statistically, the newly revised lung cancer staging system might be more promising for the accurate evaluation of the prognosis in the non-small cell lung caner patients.

• Clinical and Experimental Pediatrics
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• v.52 no.10
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• pp.1153-1160
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• 2009

Purpose:To evaluate the risk factors for mortality and prognostic factors in pediatric hemato-oncology patients admitted to the pediatric intensive care unit (PICU). Methods:We retrospectively reviewed the medical records of pediatric hemato-oncology patients admitted at the PICU of the Asan Medical Center between September 2005 and July 2008. Patients admitted at the PICU for perioperative or terminal care were excluded. Results:Total 88 patients were analyzed. Overall ICU mortality rate was 34.1%. Mean age at PICU admission was $7.0{\pm}5.7$ years and mean duration of PICU stay was $18.1{\pm}22.2$ days. Hematologic diseases contributed to 77.3% of all the primary diagnoses, and the primary cause of admission was respiratory failure (39.8%). The factors related to increased mortality were C-reactive protein level (P<0.01), ventilation or dialysis requirement (P<0.01), and hematopoietic stem cell transplantation (P<0.05). In all, 3 scoring systems were investigated [Number of Organ System Failures (OSF number), the Pediatric Risk of Mortality III (PRISM III) score, and the Sequential Organ Failure Assessment (SOFA) score]; higher score correlated with worse outcome (P<0.01). The Oncological Pediatric Risk of Mortality (O-PRISM) scores of the 21 patients who had received hematopoietic stem cell transplantation were higher among the non-survivors, but not statistically significant (P=0.203). Conclusion:The PRISM III and SOFA scores obtained within 24 hours of PICU admission were found to be useful as early mortality predictors. The highest OSF number during the PICU stay was closely related to poor outcome.

• Radiation Oncology Journal
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• v.29 no.1
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• pp.11-19
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• 2011

Purpose: To evaluate the pathological and clinical effects of preoperative chemoradiation (CCRT) in cases of locally advanced rectal cancer and to determine the predictive factors for tumor downstaging. Materials and Methods: From March 2004 to August 2008, 33 patients with locally advanced rectal cancer were treated with preoperative CCRT. Twenty-eight patients (84.8%) were treated using a concomitant boost technique while five (15.2%) patients were treated using a cone down boost technique. All patients received 50.4 Gy of irradiation and concurrent chemotherapy with 5-fluorouracil. The median follow-up duration was 24.2 months (range, 9.8 to 64.7 months). Results: Thirty-one (93.9%) patients underwent surgery. Twenty-four patients (72.7%) underwent anal sphincter-preserving surgery. The 3-year disease free survival (DFS) and overall survival rates were 63.4% and 78.8%, respectively. Post-operative factors were more important for DFS. Pathologic N stage, margin status, and pathologic differentiation were significant prognostic factors (p=0.001, 0.029, 0.030). Tumor size and lymphovascular invasion were also associated with marginal significance (p=0.081, 0.073). However, only pre-treatment T stage was a significant pre-operative factor (p=0.018). The complete pathological response rate was 9.1 %. T-downstaging was observed in ten (30.3%) patients, whereas N-downstaging was found in 24 (72.7%) patients. Pre-treatment T stage and the interval between CCRT and operation were the predictive factors for downstaging in a univariate analysis (p=0.029, 0.027). Pre-treatment carcinoembryogenic antigen was also associated with marginal significance (p=0.068). Conclusion: The survival of rectal cancer patients can be better determined based on post-operative findings. Therefore, pre-operative CCRT for downstaging of the tumor seems to be important. Pre-treatment T stage and the interval between CCRT and operation can be used to predict downstaging.

• The Korean Journal of Nuclear Medicine
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• v.32 no.6
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• pp.497-508
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• 1998

Purpose: Using rest T1-201/dipyridamole stress gated Tc-99m-MIBI/ 24 hour delay T1-201 SPECT, we investigated the predictive values of the markers of the stress-rest reversibility (Rev), T1-201 rest perfusion (Rest), T1-201 24 hour redistribution (Del) and Tc-99m-MIBI gated systolic thickening (Thk) for wall motion improvement after coronary artery bypass surgery. Materials and Methods: In 39 patients (M;F= 34:5, age $58{\pm}8$), preoperative and postoperative (3 months) SPECT were compared. 24 hour delayed SPECT was done in 16 patients having perfusion defects at rest. Perfusion or wall motion was scored from 0 to 3 (0: normal to 3: defect or dyskinesia). Wall motion was abnormal in 142 segments among 585 segments of 99 artery territories which were surgically revascularized. Results: After bypass surgery, ejection fraction increased from $37.8{\pm}9.0%$ to $45.5{\pm}12.3%$ in 22 patients who had decreased ejection fraction preoperatively. Wall motion improved in 103 (72.5%) segments among 142 dysfunctional segments. Positive predictive values (PPV) of Rev, Rest, Del, and Thk were 83%, 76%, 43%, and 69% respectively. Negative predictive values (NPV) of Rev, Rest, Del, and Thk were 48%, 44%, 58%, and 21%, respectively. Rest/gated stress/delay SPECT had PPV of 74% and NPV of 46%. Though univariate logistic regression analysis revealed Rev (p=0.0008) and Rest (p=0.024) as significant predictors, stepwise multivariate test found Rev as the only good predictor (p=0.0008). Conclusion: Among independent predictors obtained by rest T1-201/ stress gated Tc-99m-MIBI/ delayed T1-201 myocardial SPECT for wall motion improvement after bypass surgery, stress-rest reversibility was the single most useful predictor.

• Tuberculosis and Respiratory Diseases
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• v.60 no.2
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• pp.151-159
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• 2006

Background : Excision repair cross complementing gene 1 (ERCC1) not only has a protective role against carcinogens, but plays an important role in cisplatin-resistance via the repair of cisplatin-DNA adducts. This study investigated the association between the ERCC1 expression levels in sputum and survival after cisplatin-based chemotherapy in patients with inoperable non-small cell lung cancer (NSCLC). Methods : Using the sputum collected from 67 inoperable (stage IIIa-IV) NSCLC patients treated with either taxanes (33 cases) or gemcitabine (34 cases) plus cisplatin, the relative expression levels of ERCC1 and the expression of the tumor specific antigen, MAGE, were examined by the quantitative RT-PCR and RT-PCR, respectively. The response and survival were compared with the relative level of ERCC1 or MAGE expression and the treatment modality. Results : In the sputum, ERCC1 and MAGE was detected in 74.6% and 40.2% of patients, respectively. Using the median ERCC1 level, the patients were classified as having high or low ERCC1 expression. The median overall survival (MST) was significantly longer in patients with a high ERCC1 expression level than those with a low expression level (84 weeks vs. 44 weeks respectively, P=0.017). In the taxene-based treatment group, the MST was longer than the gemcitabine group (79 weeks vs. 47 weeks, respectively, P=0.03). The levels of ERCC1 were significantly higher in patients who were MAGE-positive (P=0.003). In the MAGE-negative patients, the MST was longer in the high ERCC1 group (103 weeks vs. 43 weeks, P=0.008), but not in the MAGE-positive patients (62 weeks vs. 44 weeks, P=0.348). Conclusion : ERCC1 expression in the sputum can be a prognostic factor for survival after chemotherapy in patients with inoperable NSCLC.

• The Korean Journal of Nuclear Medicine
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• v.32 no.6
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• pp.509-515
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• 1998

Purpose: The aim of this study was to evaluate whether T1-201 reinjection distinguishes viable from non-viable myocardium in patients with reverse redistribution after acute myocardial infarction. Materials and Methods: We studied 42 patients with acute myocardial infarction (age, $55{\pm}12$ years). Eighteen (43%) out of 42 showed reverse redistribution on dipyridamole stress-4 hour redistribution T1-201 single photon emission computed tomography (SPECT). T1-201 reinjection was performed at 24 hours. Reverse redistribution was defined as worsening of perfusion defect at 4 hour delayed scan. All patients underwent follow-up echocardiography in 4 months to assess regional wall motion improvement. T1-201 uptake on reinjection images were analyzed for the prediction of myocardial wall motion improvement. Results: Of 36 segments with reverse redistribution, 17 segments showed normal wall motion on echocardiography, while 19 segments showed wall motion abnormalities. Of 19 the segments with reverse redistribution, 11 (58%) showed enhanced uptake after 24 hour reinjection. Myocardial wall motion was improved in 10 of 11 segments (90%) with enhanced uptake on reinjection. Wall motion improvement was not seen in 5 of 8 segments (63%) without enhanced thallium uptake. When myocardial viability was assessed by the uptake on reinjection image, nine of 10 segments (90%) with normal or mildly decreased uptake showed improved wall motion. Wall motion was not improved in 5 of 9 segments (16%) with severely decreased uptake. Conclusion: In patients with acute myocardial infarction, T1-201 reinjection imaging on myocardial segments with reverse redistribution has a high positive predictive value in the assessment of myocardial viability.

• Information Systems Review
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• v.25 no.2
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• pp.57-76
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• 2023

This study classifies the success of creators and YouTubers who have created channels on YouTube recently, which is the most influential digital platform. Based on the actual information disclosure of YouTubers who are in the field of science and technology category, video upload cycle, video length, number of selectable multilingual subtitles, and information from other social network channels that are being operated, the success of YouTubers using machine learning was classified and analyzed, which is the closest to the YouTube revenue structure. Our findings showed that neural network algorithm provided the best performance to predict the success or failure of YouTubers. In addition, our five factors contributed to improve the performance of the classification. This study has implications in suggesting various approaches to new individual entrepreneurs who want to start YouTube, influencers who are currently operating YouTube, and companies who want to utilize these digital platforms. We discuss the future direction of utilizing digital platforms.