• Journal of Chest Surgery
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• v.56 no.3
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• pp.179-185
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• 2023

Background: Assessments of air leaks are usually performed subjectively, precluding the use of air leaks as an evaluation factor. We aimed to identify objective parameters as predictive factors for prolonged air leak (PAL) and air leak cessation (ALC) from air flow data produced by a digital drainage system. Methods: Flow data records of 352 patients who underwent lung lobectomy were reviewed, and flow data at designated intervals (1, 2, and 3 hours postoperatively [POH] and 3 times a day thereafter [06:00, 13:00, 19:00]) were extracted. ALC was defined by flow less than 20 mL/min over 12 hours, and PAL was defined as ALC after 5 days. Cumulative incidence curves were obtained using Kaplan-Meier estimates of time to ALC. Cox regression analysis was performed to determine the effects of variables on the rate of ALC. Results: The incidence of PAL was 18.2% (64/352). Receiver operating characteristic curve analysis showed cut-off values of 180 mL/min for the flow at 3 POH and 73.3 mL/min for the flow on postoperative day 1; the sensitivity and specificity of these values were 88.9% and 82.5%, respectively. The rates of ALC by Kaplan-Meier analysis were 56.8% at 48 POH and 65.6% at 72 POH. Multivariate Cox regression analysis revealed that the flow at 3 POH (≤80 mL/min), operation time (≤220 minutes), and right middle lobectomy independently predicted ALC. Conclusion: Air flow measured by a digital drainage system is a useful predictor of PAL and ALC and may help optimize the hospital course.

• Journal of Chest Surgery
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• v.42 no.2
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• pp.238-243
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• 2009

Background: Radiofrequency obliteration and endovenous laser therapy of the greater saphenous vein have recently been introduced as alternative, minimally invasive techniques for the treatment of saphenous vein incompetence. The 7 Fr. VNUS $ClosureFAST^{(R)}$ radiofrequency obliteration system was introduced in Gwang-Ju Veterans hospital. The purpose of this study is to evaluate the efficacy and complications of radiofrequency obliteration using the 7 Fr. VNUS $ClosureFAST^{(R)}$ system. Material and Method: Between May 2, 2007 and May 31, 2008, we performed radiofrequency obliteration on 90 patients. The number of males was 67 and their mean age was $57.9{\pm}11.0$ (range: $23{\sim}78$) years old. The patients underwent follow up exams at 3 weeks after the procedures and then every 3 months. The effects of treatment and the complications were reviewed. Result: The postoperative complications were ecchymosis (94.4%), pain (27.8%), paresthesia (25.6%), bullous formation (8.9%), edema (6.7%) and phlebitis (2.2%). One patient showed good blood flow after 3 weeks and one patient showed good blood flow after 3 months. The one-year success rate of radiofrequency obliteration in varicose veins was 97.6%. Conclusion: Our data showed acceptable operative results and short-term clinical results for treating varicose veins with radio frequency obliteration. Long-term follow-up and comparison of radio frequency obliteration with high ligation and stripping, previous radiofrequency ablation and endovenous laser therapy are needed in the future.

• Journal of Chest Surgery
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• v.50 no.1
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• pp.8-13
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• 2017

Background: Extracorporeal membrane oxygenation (ECMO) has been successfully used as a method for the interhospital transportation of critically ill patients. In South Korea, a well-established ECMO interhospital transport system is lacking due to limited resources. We developed a simplified ECMO transport system without mechanical ventilation for use by public emergency medical services. Methods: Eighteen patients utilized our ECMO transport system from December 2011 to September 2015. We retrospectively analyzed the indications for ECMO, the patient status during transport, and the patient outcomes. Results: All transport was conducted on the ground by ambulance. The distances covered ranged from 26 to 408 km (mean, $65.9{\pm}88.1km$) and the average transport time was $56.1{\pm}57.3minutes$ (range, 30 to 280 minutes). All patients were transported without adverse events. After transport, 4 patients (22.2%) underwent lung transplantation because of interstitial lung disease. Eight patients who had severe acute respiratory distress syndrome showed recovery of heart and lung function after ECMO therapy. A total of 13 patients (70.6%) were successfully taken off ECMO, and 11 patients (61.1%) survived. Conclusion: Our ECMO transport system without mechanical ventilation can be considered a safe and useful method for interhospital transport and could be a good alternative option for ECMO transport in Korean hospitals with limited resources.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.11
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• pp.74-79
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• 1996

This paper describes a methodology for the development of models of discrete event system(DES). The methodology is based on transformation of continuous state space into discrete one to homomorphically represent dynamics of continuous processes in discrete events. This paper proposes a formal structure which can couple DES models within a framework. The structure employs the DEVS formalism for the DES models. The proposed formal structure has been applied to develop a DEVS model for the human cardiovascular system. For this, the cardiac cycle is partitioned into a set of phases based on events identified through VisSim simulation in the CS of the electrical analog model. VisSim is the simulation tool of visual environment for developing continuous, discrete, and hybrid system models and performing dynamic simulation. For each phase, a CS of the electrical analog model for the cardiovascular system has been simulated by VisSim 2.0. To validate this model, first develop the DEVS model, then simulate the model in the DEVSIM++ environment. It has same simulation results for the data obtained from the CS simulation using VisSim. The comparison shows that the DEVS model represents dynamics of the human heart system at each phase of cardiac cycle.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.26 no.3
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• pp.155-165
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• 2019

Purpose: Although emergency care is one of the most important capabilities for novice nurses, many novice nurses have shown difficulty in emergency care in the clinical field. The purpose of this study was to provide evidence data for the future development of educational programs by analyzing the priorities in emergency care of novice nurses using the Importance-Performance Analysis. Methods: This study was designed as a descriptive survey. The participants were 197 novice nurses who worked in general hospitals from August 1 to 31, 2018. The questionnaire consisted of 'common emergency care', 'cardiovascular emergency care', 'nervous system emergency care', 'respiratory system emergency care', 'communication and teamwork competency'. Results: As a result of this study, 'communication and teamwork' among emergency cares was evaluated as the most important capability in the clinical field. In the Importance-Performance Analysis, a total of 12 items were included in the quadrant A, including 5 items related to 'cardiovascular emergency care', 4 items to 'respiratory system emergency care', 2 items to 'nervous system emergency care' and 1 item to 'common emergency care'. The results showed a need for intensive improvement in items included in quadrant A which are the high importance low performance items. Conclusion: In order to improve the emergency care of novice nurses, a variety of emergency care education programs on the nervous system and respiratory system care should be implemented as well as cardiovascular emergency care education.

• Korean Circulation Journal
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• v.53 no.1
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• pp.17-30
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• 2023

Background and Objectives: To evaluate the impact of smoking in young adults on the risk of cardiovascular disease (CVD) and the clustering effect of behavioral risk factors such as smoking, obesity, and depression. Methods: A Korean nationwide population-based cohort of a total of 3,280,826 participants aged 20-39 years old who underwent 2 consecutive health examinations were included. They were followed up until the date of CVD (myocardial infarction [MI] or stroke), or December 2018 (median, 6 years). Results: Current smoking, early age of smoking initiation, and smoking intensity were associated with an increased risk of CVD incidence. Even after quitting smoking, the risk of MI was still high in quitters compared with non-smokers. Cigarette smoking, obesity, and depression were independently associated with a 1.3-1.7 times increased risk of CVD, and clustering of 2 or more of these behavioral risk factors was associated with a 2-3 times increased risk of CVD in young adults. Conclusions: In young adults, cigarette smoking was associated with the risk of CVD, and the clustering of 2 or more behavioral risk factors showed an additive risk of CVD.

• The Korean Journal of Physiology
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• v.28 no.2
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• pp.133-141
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• 1994

The discharge patterns and peripheral nerve inputs to cardiovascular neurons were investigated in rostral ventrolateral medulla (RVLM) and raphe nucleus of cats. The data from the two were compared to determine their roles in cardiovascular regulation and the endogenous analgesic system. Animals were anesthetized with ${\alpha}-chloralose$ and single cell activities were recorded by carbon-filament microelectrode and their relationships with cardiovascular activity were analyzed. In RVLM area, a total of thirty-three cells were identified as cardiovascular neurons. During one cardiac cycle, the mean discharge rate of the neurons was $1.96{\pm}0.29$ and the peak activity was observed 45 ms after the systolic peak of arterial blood pressure. Thirteen cells could be activated antidromically by stimulation of the the $T_2$ intermediolateral nucleus. Forty-three raphe neurons were identified as cardiovascular neurons whose mean discharge rate during one cardiac cycle was $1.02{\pm}0.12$. None of these cells could be activated antidromically. Study of the interval time histogram of RVLM neurons revealed that the time to the first peak was $128{\pm}20.0\;ms$, being shorter than the period of a cardiac cycle. The same parameter found from the raphe neurons was $481{\pm}67.2\;ms$, which was much longer than the cardiac cycle length. Of seventeen RVLM neurons examined ten received only the peripheral $A{\delta}-afferent$ inputs, whereas six RVLM neurons received both $A{\delta}-$ and C-inputs; the remaining one cell received an inhibitory peripheral C-input. In contrast, nine of eleven raphe neurons were found to receive $A{\delta}-inputs$ only. We conclude that the main output of cardiovascular regulatory influences are mediated through the RVLM neurons. The cardiovascular neurons in the raphe nucleus appear to serve as interneurons transferring cardiovascular afferent information to the raphespinal neurons mediating the endogenous analgesic mechanisms.

• The Journal of Korean Medicine
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• v.28 no.3 s.71
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• pp.289-298
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• 2007

Objectives : Electrical acupoint stimulation (EAS) has been used to treat motor dysfunction of stroke patients with reportedly effective results. The purpose of this study was to evaluate the efficacy of EAS with different frequencies in treating motor dysfunction of ischemic stroke patients. Methods : The subjects of this study were sixty-two ischemic stroke patients with motor dysfunction at Kyunghee Oriental Medicine Hospital who were hospitalized for one week to one month from onset. They were treated with 2Hz or 120Hz EAS for two weeks, and motor evoked potentials (MEP) were measured before and after EAS treatment. To compare the effect of 2Hz EAS with 120Hz, we measured latency, central motor conduction time (CMCT) and amplitude of MEP before and after EAS treatment. Results : After two weeks of treatment, we compared MEP data of the affected side between the 2Hz group and the 120Hz group. The 2Hz group showed more significant improvement than the 120Hz group in latency, CMCT and amplitude (P=0.008, 0.002, 0.002). In case of the affected side MEP data divided by normal side MEP data, the 2Hz group also showed improvement on latency, CMCT and amplitude with significant differences (P=0.003, 0.000, 0.008). Conclusions : These results suggest that low frequency EAS activates the central motor conduction system better than high frequency EAS, and it means that EAS with low frequency is more helpful for motor recovery after ischemic stroke than that with high frequency.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.27 no.1
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• pp.111-134
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• 2016

The purpose of this study is to investigate and compare the intellectual structure of cardiovascular research area in Korea and the United States. For the purpose of this study, a data set was collected; one journal Korean Circulation Journal is in Korea and two journals Circulation, and Circulation Research are in the United States. Based on the frequency of citation counts, 45 authors and 53 authors were selected for author co-citation analysis. By multidimensional scaling, clustering, and factor analyses, the results demonstrate that researchers in both countries commonly tend to work on several, rather than focus on certain sub-areas. In both countries, the core areas are revealed as 'cardiovascular disease treatment', 'cardiovascular disease diagnose', 'cardiovascular disease fundamentals', and 'cardiovascular disease preventives'. One of distinctive differences between two is that research in Korea is likely to focus on clinical medicines while research in the United States tends to be on fundamental medicines. While the area of 'Disorders of Rhythm' is revealed in Korea, 'Pharmacology of the Cardiovascular System' area is found in the United States. In addition, the sub-areas of fundamental medicines such as 'Epidemiology of Cardiovascular Disease', 'Biology', 'Biochemistry', 'Physiology' are revealed distinctively in the United States.

• Molecules and Cells
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• v.25 no.3
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• pp.390-396
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• 2008

Calreticulin (CRT) is one of the major $Ca^{2+}$ binding chaperone proteins of the endoplasmic reticulum (ER) and an unusual luminal ER protein. Postnatally elevated expression of CRT leads to impaired development of the cardiac conductive system and may be responsible for the pathology of complete heart block. In this study, the molecular mechanisms that affect $Ca^{2+}$-dependent signal cascades were investigated using CRT-overexpressing cardiomyocytes. In particular, we asked whether calreticulin plays a critical role in the activation of $Ca^{2+}$-dependent apoptosis. In the cells overexpressing CRT, the intracellular calcium concentration was significantly increased and the activity of PKC and level of SECAR2a mRNA were reduced. Phosphorylation of Akt and ERKs decreased compared to control. In addition the activity of the anti-apoptotic factor, Bcl-2, was decreased and the activities of pro-apoptotic factor, Bax, p53 and caspase 8 were increased, leading to a dramatic augmentation of caspase 3 activity. Our results suggest that enhanced CRT expression in mature cardiomyocytes disrupts intracellular calcium regulation, leading to calcium-dependent apoptosis.