• Childhood Kidney Diseases
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• v.13 no.2
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• pp.146-152
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• 2009

Purpose : We performed this study to evaluate the incidence and clinical significance of antiphospholipid antibodies (aPL Ab) in Korean children with Henoch-$Sch{\ddot{o}}nlein$ purpura (HSP). Methods : The medical records of 62 patients (31 boys and 31 girls) aged $46.0{\pm}3.1$ (1-16) years with a clinical diagnosis of HSP based on the EULAR/PReS criteria were reviewed retrospectively. From the years 2007 to 2009, the sera from children with acute HSP were tested for aPL Ab such as LA, anti-cardiolipin antibody and anti-${\beta}_2$ glycoprotein I antibody. Results : LA was positive in 18 (29%) of the 62 patients with HSP and We divided the patients into the two groups LA positive group (N=18) and LA negative group (N=44). There were no significant differences between the two groups with regard to abdominal pain, arthralgia and renal involvement, but LA positive group had significantly higher C-reactive protein ($4.3{\pm}7.2$ mg/dL vs. $1.3{\pm}1.8$ mg/dL, P=0.035), erythrocyte sedimentation rate ($37.5{\pm}26.2$ mm/hr vs. $25.1{\pm}22.6$ mm/hr, P= 0.039), IgM ($148.1{\pm}48.4$ mg/dL vs. $114.9{\pm}41.5$ mg/dL, P=0.024), C3 ($143.1{\pm}21.9$ mg/dL vs. $129.7{\pm}24.5$ mg/dL, P=0.048) and C4 levels ($30.9{\pm}6.3$ mg/dL vs. $24.9{\pm}7.8$ mg/dL, P=0.002) compared with LA negative group. Conclusion : We found that the incidence of positive aPL Ab tests was relatively higher in Korean children with HSP and the presence of aPL Ab was associated with acute inflammatory process of HSP. These results suggest that the aPL Ab are involved in the pathogenesis of HSP in children.

• Phonetics and Speech Sciences
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• v.11 no.3
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• pp.57-67
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• 2019

This study aimed to investigate regional differences in the development of speech production in Korean children. A total of 619 children aged 2 to 7 years from the Jeolla, Seoul/Gyeonggi, Chungcheong, and Gyeongsang areas were included in this study. The subjects were assessed with the UTAP2 word-level test. In PWC, PMLU, and PWP, the performance was significantly lower in Gyeongsang at 2 years 11 months and in Jeolla and Chungcheong at 3 years 5 months than in Seoul/Gyeonggi. The total PCC of Gyeongsang and Chungcheong and UTAP PCC of Chungcheong were significantly lower at 2 years 11 months compared with those of Seoul/Gyeonggi, while Jeolla and Chungcheong showed significantly lower total PCC and UTAP PCC than Seoul/Gyeonggi at 3 years 5 months. However, no regional difference was observed in any indicators after the age of 3 years 6 months. These results suggest that there are regional differences in the ability to produce speech sounds at a very young age, and that the differences can be explained by the differences between Seoul/Gyeonggi and the other provinces rather than by the individual characteristics of specific regions.

• Journal of radiological science and technology
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• v.36 no.4
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• pp.305-311
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• 2013

The purpose of this study was to evaluate the Pathological Diagnosis associated with pSUV uptake of $^{18}F$-FDG PET/CT. We had enrolled 39 women that underwent $^{18}F$-FDG PET/CT before operative. We evaluated whether there was correlation between the pSUV of $^{18}F$-FDG PET/CT and prognostic factors. As a results, pSUV level increase according to tumor size but pSUV had no significant association with tumor size. pSUV of high histologic grade was higher than low histologic grade, and pSUV showed positive correlations with histologic grade. The ER and PR showed significant negative correlations with the pSUV of $^{18}F$-FDG PET/CT. Therefore, our results demonstrated that an correlation exists between pSUV and prognostic factors such as histologic grade, ER and PR.

• Journal of Periodontal and Implant Science
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• v.32 no.3
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• pp.589-602
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• 2002

Hyaluronic acid (HA)는 중요한 glycosaminoglycan 중 하나로서 단백질과 화학적 결합을 하지 않기 때문에 분리가 쉽고 결합조직의 세포간 기질의 주요 성분이다. 우리는 점탄성 고분자 hyaluronic acid를 실험실상에서 사람 태아 골모세포의 골 형성 과정에 미치는 영향을 알아보고자 하였다. 우리는 여러 농도의 HA에 대한 사람 태아 골모세포에서의 세포증식, 염기성 인산분해효소 활성, 석회화 결절 형성능, 교원질 합성능 그리고 bone sialoprotein (BSP)의 발현 정도를 검사하였다. 세포증식에서 각 농도의 HA 처리군과 대조군 간에 2일과 4일간의 결과에서 유의한 차이를 보이지 않았다. 염기성 인산분해효소 활성에서는 0.063% HA 처리군에서 음성 대조군에 비해 가장 유의한 염기성 인산분해효소 활성을 보였다 (p<0.05). 0.063% HA 처리군은 교원질 합성능에서도 가장 높은 수준을 보였다 (p<0.05). 석회화 결절 형성능에서는 0.063% HA 처리군에서 대조군에 비해 많은 염색된 석회화 결절을 보였다. BSP의 발현 정도를 분석한 Western blot에서는 대조군에 비해 0.063% HA 처리군에서 증가된 단백질 발현을 나타났다. 본 연구 결과 고분자 HA가 실험실상에서 사람 태아 골모세포의 분화를 통해 새로운 골 형성을 유도할 수 있는 능력이 있음을 시사하였다.

• Journal of Chest Surgery
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• v.30 no.12
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• pp.1205-1213
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• 1997

This study reviewed useful aspects of the intraoperative transesophageal echocardiography among the patients in whom heart surgery were undertaken between January 1996 and July 1996 at St.Pauls hospital, Medical College of Catholic University, Seoul, Korea. During that period, 61 patients were operated on because of valvular heart disease(25 patients), coronary artery disease(22 patients), congenital heart disease(13 patients), and combined coronary artery disease and valvular heart disease(1 patient). Two patients(1 redo-VSD and 1 valvular heart diease) needed repeated aortic cross clamping and complementary procedures because of incomplete initial procedures. There was no incidence of air embolism. We could observe significant relationship of cardiac output monitoring methods either by thermodilution technique and transesophageal echocardiography by linear regression analysis(p<0.001). We tested myocardial response(percentage of systolic wall thickness, PSWT) with low dose dobutamine challenge to predict post-CABG myocardial perfusion. And the test showed statistically significant resp.onse(sensitivity 76%, specificity 94.7%, positive predictive value 95%, negative predictive value 75%). These results suggest that cardiac surgeon could draw more benefits by intraoperative transesophageal echocardiography.

• Korean Journal of Otorhinolaryngology-Head and Neck Surgery
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• v.60 no.9
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• pp.454-462
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• 2017

Background and Objectives The present study aimed to investigate the effects of penetration/aspiration (P/A) on voice acoustic parameters. Subjects and Method Twenty-seven patients were analyzed with the videofluoroscopic swallowing study (VFSS) and then divided into two groups based on the modified Penetration and Aspiration Scale results. Ten patients (5 males and 5 females) were included in the Non-P/A group, and 17 patients (12 males and 5 females) in the P/A group. Stroke was the major cause of swallowing disorders. Three sustained /a/ vowels recorded in pre- and post-VFSS were analyzed. Mann-Whitney U-test was used to compare acoustic values before and after VFSS, and the receiver operating characteristics (ROC) curve with combination of significant parameters was also conducted. Results Among acoustic parameters, the length of analyzed sample (p=0.010), number of segments computed (p=0.018), total number detected pitch periods (p=0.017), and second formant (p=0.013) in pre- and post-VFSS were significantly different between Non-P/A and P/A groups. In the P/A group after VFSS, the means of these significant parameters decreased. According to ROC combined with four significant parameters, the probability of predicting P/A condition was 84% (p=0.005), the sensitivity was 80%, and the specificity was 80%. Conclusion Voice acoustic analysis can reflect voice changes by penetration/aspiration and the combination of significant parameters can also detect swallowing disorders. Therefore, voice analysis can be a reliable screening tool for patients with swallowing disorders.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.4
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• pp.154-168
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• 2021

COVID-19 has been spreading all around the world, and threatening global health. In this situation, identifying and isolating infected individuals rapidly has been one of the most important measures to contain the epidemic. However, the standard diagnosis procedure with RT-PCR (Reverse Transcriptase Polymerase Chain Reaction) is costly and time-consuming. For this reason, pooled testing for COVID-19 has been proposed from the early stage of the COVID-19 pandemic to reduce the cost and time of identifying the COVID-19 infection. For pooled testing, how many samples are tested in group is the most significant factor to the performance of the test system. When the arrivals of test requirements and the test time are stochastic, batch-service queueing models have been utilized for the analysis of pooled-testing systems. However, most of them do not consider the false-negative test results of pooled testing in their performance analysis. For the COVID-19 RT-PCR test, there is a small but certain possibility of false-negative test results, and the group-test size affects not only the time and cost of pooled testing, but also the false-negative rate of pooled testing, which is a significant concern to public health authorities. In this study, we analyze the performance of COVID-19 pooled-testing systems with false-negative test results. To do this, we first formulate the COVID-19 pooled-testing systems with false negatives as a batch-service queuing model, and then obtain the performance measures such as the expected number of test requirements in the system, the expected number of RP-PCR tests for a test sample, the false-negative group-test rate, and the total cost per unit time, using the queueing analysis. We also present a numerical example to demonstrate the applicability of our analysis, and draw a couple of implications for COVID-19 pooled testing.

• Journal of the Korean Society of Radiology
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• v.83 no.1
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• pp.3-27
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• 2022

Cardiac CT has been proven to provide diagnostic and prognostic evaluation of coronary artery disease for cardiovascular risk stratification and treatment decision-making based on rapid technological development and various research evidence. Coronary CT angiography has emerged as a gateway test for coronary artery disease that can reduce invasive angiography due to its high negative predictive value, but the diagnostic specificity is relatively low. However, coronary CT angiography is likely to overcome its limitations through functional evaluation to identify the hemodynamic significance of coronary artery disease by analyzing myocardial perfusion and fractional flow reserve through cardiac CT. Recently, studies have been actively conducted to incorporate artificial intelligence to make this more objective and reproducible. In this review, functional imaging techniques of cardiac computerized tomography are explored.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.13 no.1
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• pp.7-22
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• 2010

Purpose: Nodular gastritis is a characteristic finding of Helicobacter pylori infection in children. The aim of this study was to evaluate the difference in gene expression in the gastric mucosa of H. pylori-infected and non-infected children, and to analyze the difference in gene expression using cDNA microarray analysis of nodular gastritis caused by H. pylori infection. Methods: Twelve children (6 boys and 6 girls; mean age 9.8 years) who underwent upper gastrointestinal endoscopy and biopsy at Seoul National University Bundang Hospital were included in the study. The subjects were divided into three groups according to the presence of H. pylori infection and nodular gastritis on endoscopic examination. Gastric mucosa tissue was kept at $-70^{\circ}C$ and RNA was extracted to perform cDNA microarray analysis in each patient. Results: cDNA microarray analysis in children revealed a clear distinction between H. pylori-infected and non-infected gastric mucosa. Specifically, 182 over-expressed genes and 29 under-expressed genes were identified in H. pylori-infected gastric mucosa compared to non-infected mucosa. H. pylori-infected nodular gastritis revealed different gene expression patterns from H. pylori-infected normal gastric mucosa; five genes were over-expressed and five genes were under-expressed. Conclusion: In the presence of H. pylori infection, gastric mucosa shows distinct differences in gene expression, and nodular gastritis with H. pylori infection in children may be associated with over- or under-expression of some genes. Further studies are required to clarify the host response and the pathogenesis of nodular gastritis in children.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.6 no.1
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• pp.39-46
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• 2003

Purpose: In a retrospective study for the pediatric patients who underwent liver transplantation in the past 6 years at Samsung Medical Center, the clinical features of 5 patients with posttransplant lymphoproliferative disorder (PTLD) were analyzed. Methods: Between June 1996 and June 2002, 41 pediatric patients underwent liver transplantation. Seven of them died in the postoperative period. Thirty-five including one patient who died of PTLD were finally reviewed. Patients were divided into two groups: high risk group, EBV naive recipients of EBV-positive grafts; low risk group, the patients other than those in high risk group. The authors reviewed age at operation, immunosuppressive agent, postoperative duration until diagnosis, postoperative duration until EBV seroconversion, presence of treatment against rejection, and presenting symptoms of PTLD. Results: Five of 41 patients (12.2%) developed PTLD. All of them belonged to high risk group, and the incidence of PTLD in high risk group was 31.3% (5/16). The mean age at operation was 10.8 months old and the mean duration between operation and diagnosis for PTLD was 9.8 months. Primary EBV infection developed after a median of 6 months after transplantation. One patient was diagnosed as laryngeal and gastrointestinal PTLD and the other four, gastrointestinal PTLD. The following symptoms and signs were seen in the patients: anemia (100%), hypoalbuminemia (100%), fever (80%), diarrhea (80%), gastrointestinal bleeding (80%), and anorexia (60%). Conclusion: PTLD is one of the major complications after pediatric liver transplantation, especially in the group of high-risk recipients. Anemia, hypoalbuminemia, fever, diarrhea and gastrointestinal bleeding were features that are characteristic of PTLD. The common features of PTLD development were: (i) EBV-positive donors placed into EBV naive recipients, (ii) primary EBV infection about 6 months after transplantation, (iii) young age, about 1 year old at operation, and (iv) the requirement for intensive posttransplant immunosuppression.