• Journal of Chest Surgery
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• v.34 no.6
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• pp.447-453
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• 2001

Background: Although pulmonary resection is the standard approach for the management of pulmonary metastases from soft tissue sarcoma, most of them are unresectable and chemotherapy remains the only option. The effectiveness of the cytotoxic drugs may be limited by the toxicities that occur before the therapeutic dose is reached. The regional administration of doxorubicin using pulmonary arterial perfusion in a rodent model can produce 10 to 25 times higher concentrations in the lung than systemic administration with minimal systemic toxicities. However, it is unclear whether a high concentration of doxorubicin has beneficial effects for killing cancer cells. Material and Method: We studied this to evaluate the dose-dependent cytotoxic and apoptotic effects of doxorubicin on methylcholanthrene-induced rat fibrosarcoma(MCA) cells. This study examined the cytotoxicity and apoptosis-related gene expressions(Fas, FasL, Bax, caspase 1, caspase 2, caspase 8, Bcl-2, Bcl-xL, Bcl-xS) in MCA cells after 24 hours exposure to various concentrations of doxorubicin such as 1, 5, 10, 50, and 100 $\mu$M. Result: Dose-dependent cytotoxicity was observed after 24 hours exposure to doxorubicin. However, peak apoptosis after 24 hours exposure was observed at 5 $\mu$M of doxorubicin. Above 5 $\mu$M, apoptotic activity was decreased with dose-increment. All mRNA levels of apoptosis-related genes after 24 hours exposure were up-regulated above the control level at 1 $\mu$M of doxorubicin and then decreased by doxorubicin dose-increment except caspase 8, which showed higher levels than the control level at 5 $\mu$M. Apoptosis-related protein levels were highest at 1 $\mu$M of doxorubicin and then decreased by doxorubicin dose-increment. However, Bax and Bcl-xL proteins steadily showed higher levels than the control throughout the different concentrations of doxorubicin. Conclusion: These results suggest that apoptosis is the main cytotoxic mechanism in low concentrations of doxorubicin in MCA cells and apoptosis-related genes, such as Bax, caspase 8, and Bcl-xL, are involved. At high concentrations, doxorubicin still can kill MCA cells, even when apoptosis is inhibited, and have its propriety for achieving much cytotoxicity against MCA cells.

• Journal of Chest Surgery
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• v.38 no.2 s.247
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• pp.110-115
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• 2005

Background: The aims of this paper were to review the mid term clinical results and to analyze the preoperative risk factors of isolated aortic valve replacement (AVR). Material and Method: Between January 1992 and February 2003, 80 patients underwent isolated AVR. 58 were male and 22 were female patients, raging from 12 to 75 years of age (mean :$46.8{\pm}13.0$ years). 74 patients except one early death and 5 follow-up loss were contacted by OPD or by telephone. The mean duration of follow-up was $44.2{\pm}29.7$ months and the total cumulative period was 272.8 patient-year. Result: The complications in hospital occurred in 35 cases : 12 wound problems (11 superficial, 1 deep), 11 arrhythmias (9 temporary, 2 persistent), 3 low cardiac output, and so forth. The late deaths were 4 cases : the heart-related deaths were 2 cases ($0.7\%$ patient-year). Conclusion: The risk factors that influenced the early mortality and morbidity were older age (> 60 years)(p=0.04), poor preoperative NYHA functional class (> 3) (p=0.048), high preoperative serum creatinin level (> 1.2 mg/100 ml)(p=0.031), long operation time (aortic clamping time>90 min)(p=0.042). The same factors influenced the late mortality and morbidity. Freedom from valve-related complication was $86.4{\pm}5.3\%,$ actuarial survival rate were $96.8{\pm}2.3\%$ at 3 years and $90.8{\pm}4.6\%$ at 10 years.

• Journal of Chest Surgery
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• v.40 no.2 s.271
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• pp.90-96
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• 2007

Background: Postoperative atrial fibrillation is the most frequently arrhythmic complication associated with coronary artery bypass graft surgery. This study was designed to investigate the incidence of atrial fibrillation in patients undergoing OPCAB and on-pump CABG and to identify the risk factors associated with its development. Material and Method: 247 consecutive patients were evaluated among 306 patients who underwent the coronary artery bypass graft surgery between January, 2002 and December, 2005. 178 patients underwent OPCAB (OPCAB group) and 69 patients underwent On-pump CABG (On-pump CABG group). The incidence and the risk factors of atrial fibrillation in two groups were determined. Result: There were no significant differences between two groups with respect to the preoperative demographic characteristics of the patients. The incidences of postoperative atrial fibrillation were 25 cases (14%) in OPCAB group and 15 cases (21%) in On-pump CABG group. Age over 65 years, net positive fluid imbalance for postoperative 3 days, and chest tube bleeding for postoperative 3 days were independent predictive factors in OPCAB group. Age over 65 years and net positive fluid imbalance for postoperative 3 days were independent predictive factors in On-pump CABG group. In multivariate analysis, age over 65 years was the only risk factor of postoperative atrial fibrillation in both groups. Conclusion: Atrial fibrillation is a common complication after procedures of myocardial revascularization. There wasn't a low incidence of postoperative atrial fibrillation in OPCAB, compared with On-pump CABG. Age over 65 years was associated with postoperative atrial fibrillation irrespective of the use of cardiopulmonary bypass.

• Journal of Chest Surgery
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• v.40 no.2 s.271
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• pp.103-108
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• 2007

Background: Surgical resection is an important modality in the treatment of pulmonary metastases from various solid tumors. We analyzed 37 patients who underwent surgical treatments of pulmonary metastases in our hospital from 1996 to 2005. Material and Method: Age, sex, disease free interval, operative procedure, the number of pulmonary metastases, and lymphatic metastasis were investigated with admission and operative records, and pathologic reports. Actuarial survival and comparisons between each survival rate were calculated according to Kaplan-Meier method and log-rank test, respectively, Result: Complete resections were carried out in 34 of 37 patients. The primary tumor was carcinoma in 25 cases, sarcoma in 10, and others in 2. The number of pulmonary metastases was 1 in 25 cases and 2 or more in 12 cases. 3-year and 5-year survival rates after complete resection were 50.5% and 35.9%, respectively. 3-year and 5-year survival rates for carcinoma were 64.5% and 45.0%, respectively, and 3-year survival rate for sarcoma was 17.5%. Otherwise, none of the operative procedures, the number of pulmonary metastases, lymphatic metastasis, adjunctive therapy and the disease free interval in the case of carcinoma significantly affected the survival rates. Conclusion: Complete resection of pulmonary metastasis in well selected patients allows high long term survival rate with low mortality and morbidity. Long-term follow up and randomized prospective studies were necessary to determine the prognostic factors of pulmonary metastases after surgical resection.

• Journal of Chest Surgery
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• v.40 no.2 s.271
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• pp.109-113
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• 2007

Background: In non-small cell lung cancer (NSCLC), malignant pleural effusion is a frequently observed com-plication, and is an important negative prognostic factor. Although many studies concerned to diagnosis and treatment of malignant pleural effusion have been performed, prognostic factors of malignant pleural effusion have rarely been investigated. This study was performed to determine the prognostic factors of malignant pleural effusion n non-small cell lung cancer. Material and Method: We evaluated 33 NSCLC patients with malignant effusion treated between January 2002 and December 2003. We analyzed possible factors: gender, age, TNM Stage, fluid analysis (pH, CEA, LDH, glucose, albumin) and treatment modality. Median survival time of each factor was calculated by Kaplan-Meier method and difference of median survival time between groups of factor compared by log-rank test. The Cox proportional hazards regression model was used to confirm the significance of prognostic factor. Results: Of the 33 patients, 23 (69.7%) patients were adenocarcinoma. The median interval of the diagnosis of lung cancer and malignant effusion was 7.3 months ($25^{th}{\sim}75^{th}:\;3.9{\sim}11.8$), and the median survival time was 3.6 months (95% Confidence Interval: $1.14{\sim}5.99$). In the univariate analysis, using the log-rank test, those with an adenocarcinoma showed a relatively longer median survival time than those of a non-adenocarcinoma (4.067 vs. 1.867 months, p=0.067) without statistical significance. In the multivariate analysis, using the Cox regression, those with a non-adenocarcinoma showed a trend of high risk of cancer death than those with an adenocarcinoma without statistical significance (Relative risk; 2.754, 95% Cl: $0.988{\sim}7.672$, p=0.053). Conclusion: We could not find an independent prognostic factor of malignant pleural effusion in NSCLC. As there was a trend of high risk of cancer death according to histology, further study will be needed.

• Journal of Chest Surgery
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• v.40 no.6 s.275
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• pp.399-406
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• 2007

Background: Ischemia-reperfusion injury related to unsuccessful myocardial protection affects postoperative ventricular function and mortality during open-heart surgery. We prospectively compared the effects of administration of histidine-tryptophan-ketoglutarate (HTK) solution and cold blood cardioplegia (CBC) on myocardial protection and clinical outcome in patients undergoing mitral valve surgery. Material and Method: Seventy patients with mitral regurgitation (MR) undergoing mitral valve surgery were randomly divided into the HTK group (n=31) and the CBC group (n=31 ): eight patients were excluded. Perioperative hemodynamics, cardiac medications, pacing, postoperative outcomes and complications were recorded during the hospital stay. All patients received follow-up for at least 6 months postoperatively for morbidity and mortality. Resuか: There were no significant differences in the hemodynamics between the groups during the study period, except for the mean pulmonary artery pressure (MPAP), PCWP and CVP that were lower in the HTK group at 15 min after weaning of CBP. There were no differences for inotropic support and pacing during the 12 hrs postoperatively between the groups. CK-MB values on day 1 and day 2 were $77{\pm}54$ and $41{\pm}23$ for the HTK group and $70{\pm}69$ and $44{\pm}34$ for the CBC group, respectively (p=NS). Postoperative clinical outcomes were similar in both groups for at least 6 months during the follow-up period. Conclusion: These results suggest that the use of HTK solution is as safe as cold blood cardioplegia in terms of myocardial protection.

• Journal of Chest Surgery
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• v.42 no.6
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• pp.738-743
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• 2009

Background: There is no standardized tool and parameter that can accurately assess the sympathetic function before and after performing sympathectomy in patients with primary palmar hyperhidrosis. We examined the effective-ness of the sympathetic skin response (SSR) study for documenting the change of sympathetic denervation before and after performing selective thoracic sympathicotomy. Material and Method: We prospectively investigated the SSR from 12 healthy subjects who were diagnosed with primary hyperhidrosis. Each SSR was recorded on the right palm or sole with electrical stimuli applied to the skin at the left wrist and foot and vice versa for the controlateral side. This test was performed before, 2 weeks and 1 year after selective thoracic sympathicotomy. The data was corrected for the onset latency and the amplitude of the SSR (n=24). Result: The mean age of the 12 patients was $24.6{\pm}0.4$ years (range: 19~36) and the gender ratio was 1 : 0.7. The mean values of the preoperative, postoperative 2 weeks and postoperative 1 year onset latency and amplitude of the palmar side (n=24) were $1.46{\pm}0.24$ msec and $6,043{\pm}2,339{\mu}V$, $1.63{\pm}0.42$ msec and $823{\pm}638{\mu}V$, and $1.44{\pm}0.39$ msec and $2,412{\pm}1,546{\mu}V$, respectively. The mean values of the plantar side (n=38) were $1.83{\pm}0.42$ msec and $2,816{\pm}1,694{\mu}V$, $2.16{\pm}0.39$ msec and $1,445{\pm}1,281{\mu}V$ and $1.95{\pm}0.25$ msec and $1,622{\pm}865{\mu}V$, respectively. Among the documented parameters, only the palmar amplitude (p=0.002) showed statistical significance in recording the change of the sympathetic system within the same individual for the pre and postoperative period. Conclusion: The SSR amplitude ratio may be a useful parameter for documenting the efficacy of sympathetic denervation after selective sympathicotomy.

• Journal of Chest Surgery
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• v.42 no.6
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• pp.725-731
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• 2009

Background: Lobectomy and more extended anatomic resection are regarded as standard treatment for stage Ia non-small cell lung cancer, but approximately 15~40% of patients suffer from treatment failures such as cancer recurrence or death. The authors analyzed types and causes of treatment failures in surgically treated cases of stage Ia non small cell lung cancer. Material and Method: We retrospectively reviewed the medical records of 156 patients who had undergone complete resection for stage Ia NSCLC between Jan 1992 and Aug 2005. Patients were divided into two different treatment failure groups: cancer-related deaths and non-cancer-related deaths. Risk factors were analyzed in each group by the Kaplan-Meyer survival method and the Cox proportional hazard model. Result: Among the 156 patients, 93 were males; the mean age was 61. The median follow-up period was 33.8 months. The 5 year survival rate was 87.6%. Microscopic lympho-vascular permeation was reported in 10 patients. Recurrence was reported in 19 patients and 12 patients died due to recurrent lung cancer. Noncancer related deaths occurred in 16 patients. Risk factors for cancer recurrence and cancer related death were microscopic lympho-vascular permeation (HR=6.81, p=0.007, HR=7.81, p<0.001); for non-cancer related death, risk factors were pneumonectomy (HR=25.92, p=0.001) and postoperative cardiopulmonary complications (HR=29.67, p=0.002). Conclusion: After complete resection of stage Ia non small cell lung cancer patients, mortality includes not only cancer related deaths but also cancer unrelated deaths. Adjuvant chemotherapy is advised for patients who show microscopic lympho-vascular permeation, which is a risk factor for recurrence and for cancer related death. Patients who had pneumonectomy or who suffered from cardiac or respiratory complications need meticulous care in order to reduce comorbidity-induced death.

• Journal of Korea Water Resources Association
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• v.50 no.11
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• pp.715-723
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• 2017

Extracellular Polymeric Substances (EPS) in the water environment assemble fine, colloidal particles, such as clays, microorganisms and biomass, in large flocs, which are eventually subject to sedimentation and deposition and determine water/sediment quality and quantity. This study hence aimed to investigate the way that water and colloidal chemistry affects EPS-mediated flocculation of colloidal particles, using a jar-test experiment. Especially, ionic strength, divalent cation and humic substances concentrations were selected as experimental variables in the jar-test experiments, to elucidate their effects on EPS-mediated flocculation. A higher ionic strength increased flocculation capability, reducing electrostatic repulsion between EPS-attached colloidal particles and enhancing particle aggregation. 0.1 M NaCl ionic strength had higher flocculation capability, with 3 times larger floc size and 2.5 times lower suspended solid concentration, than 0.001 M NaCl. Divalent cations, such as $Ca^{2+}$, built divalent cationic bridges between colloidal particles and EPS (i.e., $colloid-Ca^{2+}-EPS$ or $EPS-Ca^{2+}-EPS$) and hence made colloidal particles to build into large, settelable flocs. A small $Ca^{2+}$ concentration enhanced flocculation capability, reducing suspended solid concentration 20 times lower than the initial dosed concentration. However, humic substances, adsorbed on colloidal particles, reduced flocculation, because they blocked EPS adsorption on colloidal particles and increased negative charges and electrostatic repulsion of colloidal particles. Suspended solid concentration in the tests with humic substances remained as high as the initial dosed concentration, indicating stabilization rather than flocculation. Findings about EPS-mediated flocculation in this research will be used for better understanding the fate and transport of colloidal particles in the water environment and for developing the best management practices for water/sediment quality.

• Journal of Korea Water Resources Association
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• v.53 no.8
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• pp.627-636
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• 2020

Debris flow disasters primarily occur in mountainous terrains far from cities. As such, they have been underestimated to cause relatively less damage compared with other natural disasters. However, owing to urbanization, several residential areas and major facilities have been built in mountainous regions, and the frequency of debris flow disasters is steadily increasing owing to the increase in rainfall with environmental and climate changes. Thus, the risk of debris flow is on the rise. However, only a few studies have explored the characteristics of flooding and reduction measures for debris flow in areas designated as steep slopes. In this regard, it is necessary to conduct research on securing independent disaster prevention technology, suitable for the environment in South Korea and reflective of the topographical characteristics thereof, and update and improve disaster prevention information. Accordingly, this study aimed to calculate the amount of debris flow, depending on disaster prevention performance targets for regions designated as steep slopes in South Korea, and develop an independent model to not only evaluate the impact of debris flow but also identify debris barriers that are optimal for mitigating damage. To validate the reliability of the two-dimensional debris flow model developed for the evaluation of debris barriers, the model's performance was compared with that of the hydraulic model. Furthermore, a 2-D debris model was constructed in consideration of the regional characteristics around the steep slopes to analyze the flow characteristics of the debris that directly reaches the damaged area. The flow characteristics of the debris delivered downstream were further analyzed, depending on the specifications (height) and installation locations of the debris barriers employed to reduce the damage. The experimental results showed that the reliability of the developed model is satisfactory; further, this study confirmed significant performance degradation of debris barriers in areas where the barriers were installed at a slope of 20° or more, which is the slope at which debris flows occur.