• Tuberculosis and Respiratory Diseases
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• v.42 no.2
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• pp.184-205
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• 1995

Background: Pulmonary toxicity by bleomycin has multiple mechanisms including direct tissue toxicity due to oxygen-derived free radicals and indirect toxicity through amplification of pulmonary inflammation. To evaluate the effect of chelators or free radical scavenger to lung damage induced by bleomycin, penicillamine as a copper chelator, deferoxamine as an iron chelator and vitamin E as a free radical scavenger were administered. Methods: Two hundred Wistar rats were divided into five groups: Control, bleomycin treated, bleomycin-penicillamine treated, bleomycin-deferoxamine treated, and bleomycin-vitamin E treated groups. Rats sacrificed on day 1, day 3, day 4, day 7, day 14, and day 28 after treatment. Bronchoalveolar lavage, light microscopic and immunohistologic studies for type I, III, IV collagens, fibronectin, laminin and NBD phallicidin were evaluated. Results: There was a significant increase in the total cell counts of bronchoalveolar lavage on day 1 from all treated animals and vitamin treated group showed an abrupt decrease in total cell counts with decrease of neutrophils on day 3. Bleomycin-vitamin E treated group had the least histologic changes such as pulmonary fibrosis. The alveolar basement membranes were positive for type IV collegen and laminin. Basement membranes of bleomycin, bleomycin-penicillamine, or bleomycin-deferoxamine treated groups were disrupted and fragmented on day 4 or 7. The bleomycin-vitamin E treated group had intact basement membranes until day 28. Conclusion: Bleomycin-induced pulmonary fibrosis was related to the severity of acute injury to oxygen radicals or activation of neutrophils and disruption of basement membrane. Vitamin E seemed to be the most effective antioxidant in the inhibition of bleomycin-induced pulmonary injury and fibrosis.

• Tuberculosis and Respiratory Diseases
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• v.52 no.4
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• pp.346-354
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• 2002

Background : Dyspnea and a limitation in exercise performance are important cause of disability in patients with chronic obstructive pulmonary disease(COPD). A depleted nutritional state is a common problem in patients with a severe degree of chronic airflow limitation. This study was carried out to assess the factors determining the maximum exercise capacity in patients with COPD. Methods : The resting pulmonary function, nutritional status, and maximum exercise performance was assessed in 83 stable patients with moderate to severe COPD. The nutritional status was evaluated by bioelectrical impedance analysis. Maximum exercise performance was evaluated by maximum oxygen uptake($VO_2max$). Results : Among the 83 patients, 59% were characterized by nutritional depletion. In the depleted group, a significantly lower peak expiratory flow rate(p<0.05), Kco(p<0.01) and maximum inspiratory pressure(p<0.05), but a significantly higher airway resistance(p<0.05) was observed. The maximum oxygen uptake and the peak oxygen pulse were lower in the depleted group. The $VO_2max$ correlated with some of the measures of the body composition : fat-free mass(FFM), fat mass(FM), body mass index(BMI), intracellular water index(ICW index), and pulmonary function : forced vital capacity(FVC), forced inspiratory vital capacity(FIVC), diffusion capacity(DLCO) : or maximum respiratory pressure : maximum inspiratory pressure(PImax), maximum expiratory pressure(PEmax). Stepwise regression analysis demonstrated that the FFM, DLCO and FIVC accounted for 68.8% of the variation in the $VO_2max$. Conclusion : The depletion of the FFM is significant factor for predicting the maximum exercise performance in patients with moderate to severe COPD.

• Journal of Chest Surgery
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• v.34 no.9
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• pp.653-661
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• 2001

Background: Retrograde cerebral perfusion(RCP) is one of the methods used for brain protection during aortic arch surgery. The author previously published the data, however, for the safety of it, there still remains many controversies. The author performed RCP and checked various parameters to clarify the possibility of early detection of cerebral injury. Material and Method: The author used pigs(Landrace species) weighing 25 to 30kg and performed RCP for 120 minutes. After weaning of cardiopulmonary bypass, we observed pigs for another 120 minutes. Rectal temperature, jugular venous oxygen saturation, central venous pressure were continuously monitored, and the hemodynamic values, histological changes, and serum levels of neuron-specific enolose(NSE) and S100$\beta$ protein were checked. Central venous pressure during RCP was maintained in the range of 20 to 25 mmHg. Result: Flow rates(ml/min) during RCP were 224.3$\pm$87.5(20min), 227.1$\pm$111.0(40min), 221.4$\pm$119.5(60min), 230.0$\pm$136.5(80min), 234.3$\pm$146.1(100min), and 184.3$\pm$50.5(120min). Serum levels of NSE did not increase after retrograde cerebral perfusion. Serum levels of S100$\beta$ protein(ng/ml) were 0.12$\pm$0.07(induction of anesthesia), 0.12$\pm$0.07(soon after CPB), 0.19$\pm$0.12(20min after CPB), 0.25$\pm$0.06(RCP 20min), 0.29$\pm$0.08(RCP 40min), 0.41$\pm$0.05(60min), 0.49$\pm$0.03(RCP 80min), 0.51$\pm$0.10(RCP 100min), 0.46$\pm$0.11(RCP 120min), 0.52$\pm$0.15(CPBoff 60min), 0.62$\pm$0.15(60min after rewarming), 0.76$\pm$0.17(CPBoff 30min), 0.81$\pm$0.20(CPBoff 60min), 0.84$\pm$0.23(CPBoff 90min) and 0.94$\pm$0.33(CPBoff 120min). The levels of S100$\beta$ after RCP were significantly higher than thosebefore RCP(p<0.05). The author could observe the mitochondrial swellings using transmission electron microscopy in neocortex, basal ganglia and hippocampus(CA1 region). Conclusion: The author observed the increase of serum S100$\beta$ after 120 minutes of RCP. The correlation between its level and brain injury is still unclear. The results should be reevaluated with longterm survival model also considering the confounding factors like cardiopulmonary bypass.

• Journal of Chest Surgery
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• v.34 no.9
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• pp.698-703
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• 2001

Background: Endovascular stent-graft insertion in aortic diseases is now generally accepted as an attractive alternative treatment modality. We reviewed our clinical experiences of endovascular stent-graft insertion in thoracic aorta. Material and Method: Since 1995, we performed 8 cases of endovasclar stent-graft insertion. Preoperative diagnoses were aortic aneurysms in 4, traumatic aortic ruptures in 3, and ruptured aortic pseudoaneurysm in 1. All procedures were performed in angiography room with the guidance of fluoroscopy. The stent-graft device is a custom-made 0.35mm thickness Z-shaped stainless steel wires, intertwined with each other using polypropylene suture ligation. It is covered with expanded Dacron vascular graft. Result: All procedures were performed successfully. Follow-up studies revealed 2 minimal perigraft leakages. There was no significant leakage or graft migration. 2 patients expired due to multiple organ failure and fungal sepsis. Other survivors(6) are doing well. Conclusion: Endovascular stent-graft insertion is relatively saft and effective treatment modality in the managment of various types of aortic diseases. In may be an effective alternative in aortic diseases of great surgical risk.

• Journal of Chest Surgery
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• v.33 no.7
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• pp.547-551
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• 2000

Background; The purpose of this study was to analyze the early and midterm results of Cabrol technique to assist in making future decisions on a more adequate technique for repairing aortic root diseases. Material and Method; From August 1993 to July 1999, we performed Cabrol technique in 18 patients ; 12 annuloaortic ectasia, 6 Stanford type A aortic dissection. Male and female ratio was 11;7, mean age was 46.9$\pm$12.3 years and mean follow up period was 22.5$\pm$21.5 months. We analysed the factors influencing postoperative complications and early mortality. The factors were old age(>60 years), high NYHA(>III), preoporative concomitant disease, urgency of operation, concomitant procedure, long pump preoperative concomitant disease, urgency of operation, concomitant procedure, long pump time(>200 minute), and hospital stay time (>30 days). Result; Operative mortality was 11.1%, late mortality was 11.1%, and overall mortality was 22.2%. The causes of operative death were a heart failure and an arrhythmia. The causes of late death were an acute myocardial infarction and an unknown etiology. Postoperative complications were bleeding, wound infection, toxic hepatitis, acute renal failure, and cerebral infarction. The factors influencing postoperative complications were hihg MYHA Fc(>III) (p=0.044), concomitant disease (p=0.044), long pump time(>200 minute)(p=0.015), and concomitant procedure(p=0.004). There were no significant factors influencing early mortality. Conclusion; The lower postoperative bleeding rate and no complication related to tension of anastomosis after Cabrol technique warrant its consideration in patients requiring aortic root replacement, especially without feasible mobilization of coronary arteries. However, to confirm the graft thrombosis, a more detailed study including periodic angiography will be required.

• Journal of Chest Surgery
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• v.43 no.5
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• pp.499-505
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• 2010

Background: There have been several reports using animal experiments that CD1-restricted T-cells have a key role in tumor immunity. To address this issue, we studied the expression of markers for CD1c+ myeloid dendritic cells (DCs) isolated from peripheral blood in the clinical setting. Material and Method: A total of 24 patients with radiologically suspected or histologically confirmed lung cancer who underwent pulmonary resection were enrolled in this study. The patients were divided according to histology findings into three groups: primary adenocarcinoma of lung (PACL), primary squamous cell carcinoma of lung (PSqCL) and benign lung disease (BLD). We obtained 20 mL of peripheral venous blood from patients using heparin-coated syringes. Using flow-cytometry after labeling with monoclonal antibodies, data acquisition and analysis were done. Result: The ratio of CD1c+CD19- dendritic cells to CD1c+ dendritic cells were not significantly different between the three groups. CD40 (p=0.171), CD86 (p=0.037) and HLA-DR (p=0.036) were less expressed in the PACL than the BLD group. Expression of CD40 (p=0.319), CD86 (p=0.036) and HLA-DR (p=0.085) were less expressed in the PACL than the PSqCL group, but the differences were only significant for CD86. Expression of co-stimulatory markers was not different between the PSqCL and BLD groups. Expression of markers for activated DCs were dramatically lower in the PACL group than in groups with other histology (CD40 (p=0.005), CD86 (p=0.013) HLA-DR (p=0.004). Conclusion: These results suggest the possibility that CD1c+ myeloid DCs participate in control of the tumor immunity system and that low expression of markers results in lack of an immune response triggered by dendritic cells in adenocarcinoma of the lung.

• Journal of The Korean Association For Science Education
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• v.32 no.4
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• pp.570-585
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• 2012

The Korean national curriculum for secondary school emphasizes scientific problem solving. In line with the national curriculum, many educational studies have been conducted in relation to science education. The objects of these studies were well-defined and well-structured problems. The studies were criticized for overlooking ill-defined and ill-structured problems. Some research has dealt with problem finding in ill-structured problems, which is related to creativity. There is a need for a study of scientific problem finding process in an ill-structured problem situation, because this study will help teachers wanting to teach scientific problem-finding in an ill-structured problem situation. The objective of this study was to conduct an empirical study on the scientific problem finding process in an ill-structured problem situation. One task of scientific problem finding in an ill-structured problem situation was assigned to 92 university students; thereafter, 32 of them participated in the research through interviews. Results indicated that the scientific problem finding process depended on initial clues and tentative solutions. Initial clues were affected by students' experiences, such as major classes, films, and novels. Tentative solutions were influenced by background knowledge of the tasks. Students screened information browsed on the Internet. They applied some standards for selection, particularly emphasized reliability standards, which are supposed to be studied in other contexts. All the students used assumptions to make their problems appear probable, which could be a useful tool to articulate.

• Journal of Chest Surgery
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• v.43 no.1
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• pp.11-19
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• 2010

Background: The commercially used vascular xenografts have some problems such as calcification, fibrosis and tissue degeneration that are associated with inflammatory and immunologic reactions. We compared two methods of xenograft preservation (fresh cryopreservation versus acellularized cryopreservation) of goat aorta. Material and Method: Aortic valved xenografts were harvested from adult pigs, and these were preserved using fresh cryopreservation (FC group, n=4) or acellularized crypreservation (AC group, n=4). These xenografts were implanted into adult goats. There were 2 short-term survivors (less than 100 days) and 2 long-term survivors in each group. These xenografts were explanted and they underwent microscopic examination. Result: The goats survived 31, 40, 107 and 411 days in the FC group and the other goats survived 5, 40, 363 and 636 days in the AC group. All the short-term survivors in each group expired because of rupture at the proximal anastomosis site. Marked neutrophil infiltration was observed in the FC group FC and lymphocytes were observed in the AC group. There were no differences in the occurrence of calcification, fibrosis and thrombosis among the groups. Conclusion: Some goats survived more than 100 days after the xenograft implantation irrespective of the methods of preservation. Because severe tissue degeneration developed in both groups, we think these methods are not appropriate for xenograft preservation of aorta. It was worth a preliminary trial for improving the preservation method or to modify the processing of xenografts.

• Journal of Chest Surgery
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• v.40 no.3 s.272
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• pp.168-179
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• 2007

Background: The recent trend of an increasing number of patients with acute cardiogenic shock or chronic congestive heart failure following myocardial infarction, as well as the considerable number who can not be weaned from cardiopulmonary bypass after open heart surgery, call for immediate efforts to develop affordable ventricular assist devices that are suitable for the Korean physique. Recently, a pneumatic pulsatile ventricular assist device (VAD), named DKUH-75, has been developed by the Department of Biomedical Engineering, in collaboration with the Department of Thoracic and Cardiovascular Surgery of Dankook University College of Medicine. The feasibility of the DKUH-75 VAD was evaluated on the bases of common hemodynamic variables and echocardiographic measurements in pigs, which are subjected to an acute cardiogenic shock state following myocardial infarction, using a novel coronary artery ligation method employing the ischemic preconditioning concept. Material and Method: Acute cardiogenic shock was induced in 10 Yorkshire Landrace Duroc strain pigs by ligating the left anterior descending coronary artery via an ischemic preconditioning process. The hemodynamic variables were monitored, with epicardial echocardiographic measurements performed before and one hour after the ligation. The DKUH-75 VAD was implanted into 5 pigs one hour after the onset of the shock. The hemodynamic variables and echocardiographic measurements were taken one hour after installation of the VAD. Result: The systolic, diastolic and mean systemic arterial pressures were significantly decreased in all the experimental animals one hour after the ligation. The systolic, diastolic and mean pulmonary arterial pressures were increased (Eds note: this completely contradicts the preceding statement? However, if you mean the non-experimental animals this should be stated?). The left ventricular end diastolic pressure (LVEDP) was increased, but the cardiac index decreased, An increase in the left ventricular end systolic dimension and decreases in the fractional shortening and ejection fraction were observed all animals one hour after the coronary artery ligation. In all 5 of the VAD implanted pigs, the systolic and mean systemic arterial pressures were increased, and the pulmonary arterial pressures decreased one hour after the implantation; the LVEDP decreased, but the cardiac index was significantly increased, In the echocardiographic measurements, the left ventricular end systolic dimension decreased after the implantation of the VAD, but the fractional shortening and ejection fraction significantly increased. Conclusion: Significant improvements in the hemodynamic variables and echocardiographic measurements were observed in the 5 VAD implanted animals one hour after installation, which had been subjected to an acute cardiogenic shock state by ligation of the coronary artery, indicating that the DKUH-75 VAD could help in the recovery of the myocardial function. This suggests that the DKUH-75 VAD is feasible in the short term in relation to an acute cardiogenic shock state due to myocardial infarction.

• Korean journal of communication and information
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• v.33
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• pp.115-167
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• 2006

The purpose of this study was to investigate coverage patterns of the Korean internet news media on 'US-Iraq War' and its meaning and discourse structure. The internet news media was recently established and become a popular news media to compete with old news media in Korea. The author selected the 'Oh My News' as a representative internet news media for his analysis, and collected its news items from Mar. 20, 2003 to Dec. 17, 2003. on the basis of 4 different phases of the war. He analysed the whole of news items with various semiotic and discourse analytic methods, especially applying for Bell's concepts of time and discourse structure. As a result of this study, first of all, it was found that the 'Oh My News' tended to cover this war so different ways as the old news media did. It did not pay attention to the procedure of war, especially, battlefields, fighting between US and Iraq, damages and casualties. But, instead, it paid attention to many doubts about intention of US government and the President, Bush, dichotomous shift between pro-America and anti-America, rightness of dispatching Korean army into Iraq, etc. Secondly, it functioned as a kind of alternative media to speak up different voices comparing with those of old media. It tended to suggest different perspectives and opinions, while the old media tended to follow American perspectives and opinions. Thirdly, it became as a kind of new media setting agendas for this war in Korean society. It played a very important role for setting agendas for various issues related with this war. In conclusion, the internet news media has recently become a kind of new news media for suggesting alternative or different opinions, setting agendas, initiating discourses, etc., even though it still has may problems of becoming so called orthodox news media.