• 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.

• Clinical and Experimental Pediatrics
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• v.45 no.3
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• pp.331-338
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• 2002

Purpose : To investigate the feature of the range of measles in 2000, we studied epidemics of the measles in western Kyungnam District. Methods : Among 489 patients under 15 years of age who visited or were admitted to in our hospital from January to December in 2000, we selected 344 patients whose measles IgM antibody was positive. We investigated age, monthly incidence, clinical features, vaccination history, and measles IgG antibody. Results : Patients under 12 months of age occupied the largest proportion(36.9%). Patients firstly occurred in May and geometrically increased from October. Fever, cough and rashes were observed in all patients but conjunctivitis in 54.9%, Koplik spot in 23.8%. The first vaccination ratio was 41.8%. Compared with the number of patients and the first vaccination ratio, the first vaccination ratio was the lowest under 12 months of age. After that age group, the number of patients was decreased as the first vaccination ratio was increased. Among 152 patients sampled for measles IgG antibody, 35 patients had received the first vaccination and 6 patients had received the second vaccination. Among 35 patients who received the first vaccination, 22(62.9%) patients were negative of measles IgG antibody. Among 6 patients who received the second vaccination, 3(50%) patients were negative. Conclusions : Measles patients under 12 months still dominated. Therefore, routine vaccination of single measles vaccine, is currently done at 6 month when measles are prevalent, should be considered. High first vaccination failure suggests problems of vaccines itself, transport and storage rather than vaccination methods. Therefore a thorough investigation should be made.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.5
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• pp.249-256
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• 2006

Purpose: Although computed tomography (CT) is widely used for diagnosing liver metastasis from colorectal cancer, diagnostic accuracy of CT is not satisfactory. Magnetic resonance (MR) imaging and F-18 FDG PET has been reported to be superior to CT. However, studies on direct comparison of PET and MR are scarce. We compared the diagnostic accuracy of FDG PET and MR in detecting liver metastasis from colorectal cancer. Materials and Methods: Among 363 colorectal cancer patients who underwent F-18 FDG PET (ECAT, Siemens-CTI, Knoxville; Gemini, Philips, Milpitas, U.S.), 26 patients (M:F=17:9, age=$62{\pm}11$) underwent MR to evaluate suspicious metastatic liver lesions. Finally, 35 liver lesions detected by CT from 26 patients were enrolled for analysis. PET and MR results were compared with pathologic reports, clinical findings or follow-up results. Results: Of the 35 lesions, 18 lesions (51.4%) were diagnosed as liver metastases, while remaining 17 (48.6%) as benign. The sensitivity and the specificity of PET were 94.4% and 94.1%, respectively, compared to 100% and 82.4% for MR. MR and PET was concordant in 30 lesions (85.7%: 17 metastatic (94.4%) and 13 benign (76.5%) lesions. ROC curve analysis revealed maximal SUV of 3.1 as the optimum standard in differentiating metastatic from benign liver lesions (AUC=0.897, p<0.001, sensitivity 83.3%, specificity 94.1%). For small lesions less than 1 cm ln diameter (n=20), diagnostic accuracy of PET was comparable to that of MR. Conclusion: F-18 FDG PET showed good diagnostic performance in detecting liver metastasis from colorectal cancer, which was comparable to MR.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.4 no.1
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• pp.28-33
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• 2001

Purpose: H. pylori infection is thought to contribute to iron-deficiency anemia, especially during puberty. The ferritin protein Pfr of H. pylori is homologous to eukaryotic and prokaryotic ferritins. The purpose of this study was to analyze the H. pylori pfr status in gastric biopsy specimens according to clinical data, including antral gastritis with or without iron-deficiency anemia. Methods: A total of 26 H. pylori-positive patients aged from ten to 18 years were categorized into subgroups based on the presence or absence of iron-deficiency anemia. All of them had antral gastritis. Sixteen patients were proved to have iron-deficiency anemia by hematological study, two of which had a duodenal ulcer. The other ten patients showed normal hematological findings. DNA isolation was performed from each of the gastric biopsy specimens. PCR amplification of the pfr gene coding was done using two sets of primers. The pfr region, 501 bp, was generated by linking the sequences of the two PCR products. The nucleotide and protein sequences were compared between the pfr regions from Korean H. pylori strains and the NCTC 11638, 26695, and J99 strain, which were obtained from the Genbank. Sequence comparisons were also performed for the pfr regions between the iron-deficiency anemia (+) and (-) groups. Results: Analysis of the complete coding region of pfr gene revealed three sites of mutation. The Ser39Ala mutation was found in 100% (26/26), Gly111Asn in 26.9% (7/26), and Gly82Ser in 11.5% (3/26). There were no significant differences in the mutations of the pfr regions between the iron deficiency anemia (+) and (-) groups. Conclusion: The mutation in the pfr gene did not relate with the clinical phenotype, iron deficiency anemia. Further studies are needed on the aspects of host side or other complex factors to elucidate anemia. Further studies are needed on the aspects of host side or other complex factors to elucidate the mechanisms by which the H. pylori infection might lead to iron deficiency anemia.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.6 no.1
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• pp.1-9
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• 2003

Purpose: To investigate the relation of the gastric epithelial cell proliferation, apoptosis and genotypes of H. pylori in children. Methods: Histologic grading by updated Sydney system, PCNA immunostaining, TUNEL method and the genotypes (cagA, picB and iceA) by PCR were performed in H. pylori positive (N=20) and negative (N=20) gastric biopsy specimens. Results: PCNA index was significantly different between H. pylori positive children ($77.4{\pm}13.12$) and H. pylori negative children ($52.3{\pm}12.20$) (p=0.000). There were positive correlations between PCNA index and H. pylori density (r=0.624, p=0.000), polymorphonuclear neutrophil activity (r=0.460, p=0.005) and chronic inflammation (r=0.433, p=0.009). Apoptosis index of H. pylori positive children ($0.70{\pm}0.411$) was significantly higher than of H. pylori negative children ($0.14{\pm}0.201$) (p=0.000). Positive correlations between apoptosis index and H. pylori density (r=0.691, p=0.000), polymorphonuclear neutrophil activity (r=0.585, p=0.000) and chronic inflammation (r=0.535, p=0.001) were noted. As PCNA index increased, apoptosis index significantly increased (r=0.527, p=0.001). The positive rates of genotypes were cagA 90%, picB 75%, iceA1 60% and iceA2 15%, respectively. There were no significant correlations between the status of the genotypes and PCNA index, apoptosis index, the endoscopic findings and the histologic findings. Conclusion: PCNA index and apoptosis index in H. pylori positive children were higher than in H. pylori negative children but were not related to H. pylori genotypes. This study suggested that correlatively increased gastric epithelial cell proliferation and apoptosis are important to pathogenesis of H. pylori infection in children.

• Clinical and Experimental Pediatrics
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• v.46 no.5
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• pp.480-483
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• 2003

Purpose : We evaluated clinical manifestations and laboratory findings in patients with measles according to C-reactive protein(CRP) concentration. Methods : A retrospective analysis was performed using the medical records of patients with measles at The Catholic University of Korea, Daejeon St. Mary's Hospital from October 1999 to May 2000. We divided the patients with measles into four groups according to CRP level, i.e., those with below 5 mg/L(134 patients, negative group), those with 6-19 mg/L(85 patients), those with 20-49 mg/L(27 patients), and those over 50 mg/L(7 patients). We compared clinical and laboratory characteristics among these four groups. Results : The mean CRP level of all patients was $11.1{\pm}7.5mg/L$. No statistical differences were present between the negative group and the 6-19 mg/L group or the 20-49 mg/L group in the duration of fever, hospitalization days, complications determined with longer hospitalization for more than eight days, white blood cell count, and incidence of hepatitis. Compared with the negative group, the over 50 mg/L group showed a longer duration of fever($4.7{\pm}1.7$ vs $7.2{\pm}3.9days$), duration of hospitalization($5.4{\pm}1.4$ vs $9.4{\pm}4.7days$), incidence of complications(5.2% vs 42.9%) and a higher mean level of WBC count($5,900{\pm}2,700/mm^3$ vs $12,700{\pm}6,700/mm^3$). With an increasing CRP level, there was a tendency for the duration of fever, complications and WBC count to increase. However the levels of liver enzymes(AST/ALT) were not associated with CRP level. Conclusion : A CRP level of over 50 mg/L in measles is associated with severity and complications.

• Journal of fish pathology
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• v.11 no.1
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• pp.77-81
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• 1998

By standardized method, Bacillus subtilis BGA, Bacillus cereus var. mycoides ATCC 11778, and Micrococcus luteus ATCC 9341 were seeded on the muller hinton agar (Difco) plate, and pH was adjusted to 6.0, 7.2, and 8.0. Five agar plates, B. subtilis (pH 6.0), B. cereus (pH 6.0), B. subtilis (pH 7.2), B. subtilis (pH 8.0), and M. luteus (pH 8.0), were employed as test plates of modified EEC 4-plate method. Oxytetracycline (OTC) with a diet was orally administered to flounder, Paralichthys olivaceus, at 100 mg/kg once a day. After oral administration, modified EEC 4-plate method by the three screening test using muscle-direct, extraction-disk and direct-disk methods was conducted for 3 fish at 1, 3, 5, 10, 15, 20, 25 and 30 days. Muscle-direct treatment of B. subtilis (pH 6.0) was found to be dubious positive (${\pm}$) at the 1st day after the administration; thereafter, it was found to be negative to the last day of the experiment. Extraction-disk and direct-disk treatment of B. subtilis (pH 6.0) were found to be negative from the 1st day to the last day after the administration. B. subtilis (pH 7.2), B. subtilis (pH 8.0), and M. luteus (pH 8.0) by the three screening tests, were found to be negative all the way after the administration. On the other hand, B. cereus (pH 6.0) by the three screening tests was clearly found to be positive for the first 15 days after the administration, and then muscle-direct and direct-disk treatment of B. cereus (pH 6.0) were found to be dubious positive at 20th days after the administration. However extraction-disk treatment of B. cereus (pH 6.0) was clearly found to be negative at the same stage; thereafter, the three screening tests of B. cereus (pH 6.0) were found negative to the last of the experiment. These findings showed that to have equal sensitivity to those determination for the residual detection of OTC, and also confirmed that B. cereus was effective test organism for the monitoring of OTC.

• Tuberculosis and Respiratory Diseases
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• v.61 no.1
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• pp.34-40
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• 2006

Background: Extubation failure was associated with poor prognosis and high hospital mortality. Cuff leak test (CLT) has been proposed as a relatively simple method for detecting laryngeal obstruction that predispose toward postextubation stridor (PES) and reintubation. We examined the risk factors of extubation failure and evaluated the usefulness and limitation of CLT for predicting PES and reintubation. Methods: Thirty-four consecutive patients intubated more than 24 hours were examined. The subjects were evaluated daily for extubation readiness, and CLT was performed prior to extubation. Several parameters in the extubation success and failure group were compared. The accuracy and limitation of CLT were evaluated after choosing the thresholds values of the cuff leak volume (CLV) and percentage (CLP). Results: Of the 34 patients studied, 6 (17.6%) developed extubation failure and 3 (8.8%) were accompanied by PES. The patients who had extubation failure were more likely to have a longer duration of intubation and more severe illness. The patients who developed PES had a smaller cuff leak than the others: according to the CLV ($22.5{\pm}23.8$ vs $233.3{\pm}147.1ml$, p=0.020) or CLP ($6.2{\pm}7.3$ vs $44.3{\pm}24.7%$, p=0.013). The best cut off values for the CLV and CLP were 50ml and 14.7%, respectively. The sensitivity, negative predictive value, and specificity of CLT were relatively high, but the positive predictive value was low. Conclusion: The likelihood of developing extubation failure increases with increasing severity of illness and duration of intubation. A low CLV or CLP (<50ml or 14.7%) is useful in identifying patients at risk of PES, but the CLT is not an absolute predictor and should not be used an indicator for delaying extubation.