• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.14 no.1
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• pp.59-66
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• 2011

Purpose: We previously reported that concurrent reactivation of latent Epstein-Barr virus (EBV) in children with hepatitis A virus (HAV) infection is common and EBV reactivation with HAV infection adversely affects the clinical features of hepatitis. However, the incidence of concurrent reactivation was not accurate because the detection of EBV reactivation was based on serologic methods. Therefore, we studied the effects of polymerase chain reaction (PCR)-proven EBV reactivation, thus a more precise concurrence, on acute HAV infection in children. Methods: PCR were conducted in 34 patients, who had enrolled previous study and diagnosed with acute HAV infection between January 2008 and June 2010. Their medical records were reviewed. Results: Among 34 patients with acute HAV infection, 12 patients (35.3%) had EBV reactivation which was proven using serologic and molecular biologic techniques. There were significant differences in the peak levels of AST and ALT between the reactivated and non-reactivated groups (p=0.001 and p<0.001, respectively). The duration of full recovery from hepatitis was more prolonged in the reactivated group (p<0.001). Clinical parameters, such as serum protein (p<0.001) and albumin concentrations (p<0.001), atypical lymphocyte count (p=0.001), prothrombin time-international normalized ratio (PT-INR, p<0.001), and splenomegaly (p<0.001), showed significant differences. The clinical features in the reactivated sub-group >10 years of age revealed more liver dysfunction compared to the non-reactivated sub-group. A comparison with a previous study was performed. Conclusion: PCR-proven reactivation of latent EBV in children with HAV infection is common and EBV reactivation with HAV infection adversely affects the clinical features of hepatitis, especially in older children.

• Radiation Oncology Journal
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• v.28 no.3
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• pp.117-124
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• 2010

Purpose: To analyze the postoperative radiotherapy results and prognostic factors in patients with WHO grade 3 and 4 gliomas. Materials and Methods: A total of 99 patients with malignant gliomas who underwent postoperative radiotherapy between 1988 and 2007 were enrolled in this study. Total resections, subtotal resections ($\geq$50%), partial resections (<50%), and biopsies were performed in 16, 38, 22, and 23 patients, respectively. In total there were 32, 63 and 4 WHO grade 3, 4, and unspecified high grade gliomas, respectively. The biologically equivalent dose was in the range of 18.6 to $83.3\;Gy_{10}$ (median dose, $72.2\;Gy_{10}$). We retrospectively analyzed survival rate, patterns of failure, prognostic factors, and adverse effects. Results: The median follow-up time was 11 months and there were 54 patients (54.5%) with local failure. The one and 2-year survival rates were 56.6% and 29.3%, respectively, and the median survival duration was 13 months. The one and 2-year progression-free survival rates (PFS) were 31.3% and 18.2%, respectively, and the median PFS was 7 months. The prognostic factors for overall survival were age (p=0.0001), surgical extents (subtotal resection, p=0.023; partial resection, p=0.009; biopsy only, p=0.002), and enhancement of tumor in postoperative imaging study (p=0.049). The factors affecting PFS were age (p=0.036), tumor enhancement of the postoperative imaging study (p=0.006). There were 3 patients with grade 3 and 4 side effects during and after radiotherapy. Conclusions: In addition to age and surgical extents, tumor enhancement of the postoperative imaging study was included in the prognostic factors. The most common relapse patterns were local failures and hence, additional studies are needed to improve local control rates.

• Journal of Chest Surgery
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• v.35 no.5
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• pp.350-355
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• 2002

Background: Most of pulmonary regurgitation with or without stenosis appears to be well tolerated early after the repair of pulmonary outflow tract. However, it may result in symptomatic right ventricular dilatation, dysfunction and arrhythmias over a long period of time. We studied the early outcome of pulmonary valve replacement with tissue valves for patients with the above clinical features. Material and Method: Sixteen consecutive patients who underwent pulmonary valve replacement from September 1999 to February 2002 were reviewed(9 males and 7 females). The initial diagnoses included tetralogy of Fallot(n=11), and other congenital heart anomalies with pulmonary outflow obstruction(n=5). Carpentier-Edwards PERIMOUNT Pericardial Bioprostheses and Hancock porcine valves were used. The posterior two thirds of the bioprosthetic rim was placed on the native pulmonary valve annulus and the anterior one third was covered with a bovine pericardial patch. Preoperative pulmonary regurgitation was greater than moderate degree in 13 patients. Three patients had severe pulmonary stenosis. Tricuspid regurgitation was present in 12 patients. Result: Follow-up was complete with a mean duration of 15.8 $\pm$ 8.5months. There was no operative mortality. Cardiothoracic ratio was decreased from 66.0 $\pm$ 6.5% to 57.6 $\pm$ 4.5%(n=16, p=0.001). All patients remained in NYHA class I at the most recent follow-up (n=16, p=0.016). Pulmonary regurgitation was mild or absent in all patients. Tricuspid regurgitation was less than trivial in all patients. Conclusion: In this study we demonstrated that early pulmonary valve replacement for the residual pulmonary regurgitation with or without right ventricular dysfunction was a reasonal option. This technique led to reduce the heart size, decrease pulmonary regurgitation and tricuspid regurgitation as well as to improve the patients'functional status. However, a long term outcome should be cautiously investigated.

• Journal of Chest Surgery
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• v.35 no.11
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• pp.779-784
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• 2002

Recently, the number of coronary artery bypass surgery(CABG) is increasing according to the increasing incidence of coronary artery disease. However, CABG is not a definite corrective surgery; therefore, in some patients, redo-CABG may be required. We retrospectively reviewed our redo-CABG experiences to help future redo-CABG. Material and Method: From January 1991 to April 2001, 14 cases of redo-CABG were performed in Yonsei Cardiovascular Center(M:F＝12:2) and mean age was 61,7 $\pm$ 7.1(47-72) years. Mean time from 1st. CABG to redo-CABG was 121.9 $\pm$ 50.5(6.1-179.6) months. Thirteen cases were conventional on-pump CABG and one case was off-pump CABG. In two patients, mitral valve re-replacement and mitral valve repair were performed each. All redo-CABG were performed through mid-sternotomy. During redo-CABG, left internal mammary artery and saphenous vein grafts were used in 6 patients, left internal mammary artery and left radial artery grafts were used in 2 patients, left internal mammary artery and gastroepiploic artery were used in one patient and only greater saphenous veins were used in 5 cases(In one case, cephalic vein was also used). The number of mean distal anastomosis was 2.1 $\pm$ 0.9(1-4). Result: There were no operative death and no perioperative myocardial infarctions and cerebrovascular accidents or other heart related complications. Mean follow up duration was 40.1 $\pm$ 38.6(1.1-118.5) months. During follow up period, angina was re-developed in one patient 13 months after operation. Two patients died of end-stage renal failure 14.8 months and 116.3 months after redo-CABG, respectively. During follow up period, coronary angiography was performed in 3 patients, and all grafts were patent. At last follow up, mean Canadian class was 1.3. Kaplan-Meier survival at 9 years was 90.0 $\pm$ 9.5% and event free survival at 9 years was 71.4 $\pm$ 6.9%. Conclusion: After redo-CABG, all patients improved their angina symptom and daily activity. And long-term survival after redo-CABG was excellent. Therefore, if patients have indications for redo-CABG, thenredo-CABG must be strongly recommended and performed.

• Journal of Chest Surgery
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• v.40 no.4 s.273
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• pp.292-296
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• 2007

Background: This retrospective study was undertaken to assess the effectiveness of the 8-French (Fr) catheter ($Pleuracan^{(R)}$) for the initial treatment of primary spontaneous pneumothorax. Material and Method: Between July 2004 and July 2006, 59 patients (72 cases) underwent a closed thoracostomy for primary spontaneous pneumothorax. We divided these patients into two groups: group T (large bore (>20 Fr) chest tube group) and group P ($Pleuracan^{(R)}$ group). Result: Initially, the $Pleuracan^{(R)}$ catheters were inserted in 41 cases. There were four catheter malfunctions (9.8%) : three cases had a subsequent closed thoracostomy with a large bore chest tube. Ultimately, there were 34 cases in group T and 38 cases in group P. There were no significant differences in indwelling catheter time ($T:\;2.1{\pm}1.5\;days,\;P:\;2.1{\pm}1.3\;days$), hospital stay ($T:\;6.4{\pm}5.4\;days,\;P:\;5.2{\pm}2.9\;days$) and complications (T: 3%, P: 0%) between the two groups. The percentage of cases that needed intravenous analgesics in group P was 60% (23/38); this was significantly lower than the number for group T (90%, 31/34) (p=0.003). In a subgroup of patients that did not undergo bullectomy(T: 17 cases, P: 19 cases), there were no significant differences in the duration of air leakage ($T:\;0.5{\pm}0.7\;days,\;P:\;0.5{\pm}1.2\;days$) and in the percentage of patients with complete lung re-expansion (T: 94%, P: 84%) between the two groups. Conclusion: Application of the $Pleuracan^{(R)}$ catheter for the initial treatment of primary spontaneous pneumothorax was as effective as the large bore chest tube.

• Journal of Chest Surgery
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• v.43 no.2
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• pp.139-143
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• 2010

Background: Thoracic empyema remains a serious problem despite the availability of modern diagnostic methods and appropriate antibiotics. The condition presents in many different forms and stages that require different therapeutic options. Video-assisted thoracic surgery (VATS) has become increasingly popular for use in the treatment of empyema. Material and Method: From January 2005 to May 2009, VATS was performed in 36 patients with pleural empyema and for whom chest-tube drainage and antibiotic therapy had failed or the CT scan showed multiseptate disease. The perioperative clinical factors were analyzed for all the study patients. Result: All the patients underwent VATS, but it was necessary to convert to thoracotomy in one patient. The mean operation time was $90{\pm}38.5\;min$. For the operative evaluation, 11 patients were compatible with ATS stage III. The duration of chesttube insertion was $11.9{\pm}5.8$ (3~24) days. One patient did not improve and therefore this patient underwent additional open drainage. At discharge, costophrenic angle blunting was observed in 22 patients, pleural thickening was noted in 20 patients, both were noted in 17 patients and neither was noted in 11 patients. However, at follow-up, each of these changes was observed in 9, 7, 4 and 24 patients, respectively. All except one patient showed radiographic improvement. Conclusion: VATS is suitable for the treatment of early and fibrinopurulent thoracic empyema, and even in selected patients with stage III disease.

• Journal of Chest Surgery
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• v.43 no.5
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• pp.513-517
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• 2010

Background: Diaphragmatic plication through a thoracoscopic approach has been an effective modality to treat diaphragmatic enventration. However, the conventional technique for thoracoscopic plication has some disadvantages. We have developed an improved and simplified technique with utilizing the head up position, $CO_2$ insufflation and figure-of-eight sutures. Material and Method: Between October 2005 and September 2009, 9 patients with diaphragmatic paralysis underwent repair using our modified technique. The mean patient age was $38.5{\pm}53.0$ years (range: 2~76 years). Result: The mean operation time was $46.7{\pm}15.9$ min (range: 30~85 min). None of the patients died due to this procedure, but there was one case of prolonged air leakage, and a case of re-expansion pulmonary edema, which required 3 days of ventilator support after the procedure. The mean hospital stay was $6.22{\pm}2.04$ days (range: 4~11 days). The mean follow-up duration was $27.2{\pm}11.6$ months (range: 2~43 months). All the patients had their symptoms relieved and there was no recurrence of eventration except for one patient who developed more than 2 cm elevation of the diaphragm compared to the immediate post-operation status. Conclusion: With our technique, thoracoscopic diaphragmatic plication was feasible via using only three 5 mm ports and without a working window and the midterm results were favorable. Therefore, we advocate thoracoscopic diaphragmatic plication as a preferred technique to the conventional open plication technique.

• Tuberculosis and Respiratory Diseases
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• v.52 no.5
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• pp.475-484
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• 2002

Background : Unresectable non-small cell lung cancer has a poor response to chemotherapy and has an unfortunate prognosis. More effective and less toxic cytotoxic agents are needed to improve the outcome of these patients. The efficacy and safety of vinorelbine monotherapy in these advanced lung cancer patients was evaluanted. Materials and Methods : Sixteen patients with non-small cell lung cancer in stage III or IV, who received vinorelbine alone as an initial anticancer chemotherapy from June 1996 to December 2000 were enrolled in this study. Vinorelbine was given intravenously at a dose 30mg/$m^2$ every week. Results : A mong the sixteen patients, six had a partial response(38%) and the median survival was 16 weeks. The median response duration was 27 weeks (95% CI 6-47), and the time to progression was 16 weeks(95% CI 6-26). Among a total of 112 cycles, neutropenia(WHO grade 3 or 4) and anemia(grade 3) occurred in 9% and 3%, respectively. Only 1 patient required hospitalization for neutropenic fever. Non-hematologic toxicity was minor and was easily controlled. Conclusion : Vinorelbine monotherapy was well tolerated, and moderately effective in patients with advanced non-small cell lung cancer.

• Tuberculosis and Respiratory Diseases
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• v.53 no.6
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• pp.612-618
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• 2002

Background : Bronchoscopy is an important diagnostic and a therapeutic tool in chest medicine. However, most patients feel that a bronchoscopy is an unpleasant procedure, and it is important to sedate the patients appropriately, particularly where repetitive examinations are required. Midazolam is a sedative drug with amnestic qualities and a rapid 2 hour half-life. This study have attempted to determine the safety, appropriate dosage, and the effect of midazolam premedication in patients who underwent a bronchoscopy. Methods : One hundred and eighty consecutive patients undergoing bronchoscopy were enrolled in this study. The patients received a midzolam doses of 0.03 mg/kg, 0.06 mg/kg, or a placebo. An additional dose of lidocaine, the total number of coughs, and the duration of the procedures were recorded with monitoring the the blood pressure, heart rate, and oxygen saturation. The level of satisfaction was assessed by the patient, bronchoscopist, and the nurse. Results : The blood pressure, pulse rates, oxygen saturation, number of coughs, lidocaine dose, and procedure time in the 3 groups were similar. There was a trend for the midazolam 0.03 mg/kg group to satisfy bronchoscopists more than the other two groups. The nurses' acceptability was lower in the midazolam 0.06 mg/kg group than the other groups. The patients' acceptablity was greater in both the midazolam 0.03 mg/kg and 0.06 mg/kg groups than in the control group. Conclusion : Sedation with low doses of intravenous midazolam is a safe technique for fiberoptic bronchoscopy with a low morbidity and high acceptable to patients and bronchoscopists.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.2
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• pp.94-101
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• 1989

Transport properties of 2DEG at AlGaAs/GaAs interface such as average electron energy, flight distance, each valley occupancy ratio, average electron velocity for various fields are investigated by MONTE-CARLO method. As the electric field increases, more electrons transit drastically from (000) valley to (000) upper valley. This phenomenon shows the nonstationary effect such as velocity overshoot. The duration of the transient decreases from about 1.4 psec for electric field E = 7KV/cm to about 0.7 psec for 12KV/cm. The average electron velocity during transient transport in 2DEG is about 8 times the steady-state velocity for E = 12KV/cm at room temperature. In comparison with bulk GaAs the peak velocity in the 2DEG is higher than that in even pure bulk GaAs at electric field E = 7 KV/cm. On the basis of the fact that the electrons in the 2DEG have larger peak velocity and shorter transient time of velocity than those in the bulk GaAs, it is suggested that the device with 2DEG may obtain higher mobility than that with bulk GaAs.