• Journal of Chest Surgery
• /
• v.20 no.1
• /
• pp.13-21
• /
• 1987

To clarify the difference between the outcome of warfarin anticoagulation and the antiplatelet [Aspirin, Dipyridamole] therapy after bioprosthetic heart valve replacement, we compared the following two groups. Group I [Warfarin group] consisted of 557 patients undergone lonescu - Shiley valve replacement between January, 1979 and December, 1985, and treated with scheduled warfarin therapy at Seoul National University Hospital. Group II [Antiplatelet group] consisted of 128 patients undergone lonescu - Shiley, Carpentier - Edwards or Wessex bioprosthetic valve replacement between March, 1983 and December, 1986, and treated primarily with antiplatelet therapy [Aspirin plus Dipyridamole] at SeJong General Hospital. The two groups were similar with respect to age, number of valves utilized per patient, type of operation and risk factors of thromboembolism. In group I, 522 patients excluding 35 hospital death [hospital mortality 6.3%], and in group II, 119 survivors excluding 9 hospital death [hospital mortality 7.0%] were followed. In group I, there were 13 fatal complications, of which seven were thromboembolic [0.6% / pt-yr] and six hemorrhagic [0.5%/pt-yr] during the period of four years. In group II, there were 3 fatal thromboembolic complications [2.3%/pt-yr] during the period of four years. This showed no statistically significant difference. Apart from fatal complications, there were lots of warfarin related minor complications in group I comparing with those of group II. The actuarial probability of the freedom from thromboembolism and of the freedom from fatal complications were very similar at each corresponding years postoperatively. As a result, warfarin anticoagulation in patients with bioprosthetic valve replacement did not reveal any significant advantages over antiplatelet therapy.

• Journal of Korean Neurosurgical Society
• /
• v.58 no.4
• /
• pp.350-356
• /
• 2015

Objective : Cases of contralateral radiculopathy after a transforaminal lumbar interbody fusion with a single cage (unilateral TLIF) had been reported, but the phenomenon has not been explained satisfactorily. The purpose of this study was to determine its incidence, causes, and risk factors. Methods : We did retrospective study with 546 patients who underwent a unilateral TLIF, and used CT and MRI to study the causes of contralateral radicular symptoms that appeared within a week postoperatively. Clinical and radiological results were compared by dividing the patients into the symptomatic group and asymptomatic group. Results : Contralateral symptoms occurred in 32 (5.9%) of the patients underwent unilateral TLIF. The most common cause of contralateral symptoms was a contralateral foraminal stenosis in 22 (68.8%), screw malposition in 4 (12.5%), newly developed herniated nucleus pulposus in 3 (9.3%), hematoma in 1 (3.1%), and unknown origin in 2 patients (6.3%). 16 (50.0%) of the 32 patients received revision surgery. There was no difference in visual analogue scale and Oswestry disability index between the two groups at discharge. Both preoperative and postoperative contralateral foraminal areas were significantly smaller, and postoperative segmental angle was significantly greater in the symptomatic group comparing to those of the asymptomatic group (p<0.05). Conclusion : The incidence rate is not likely to be small (5.9%). If unilateral TLIF is performed for cases when preoperative contralateral foraminal stenosis already exists or when a large restoration of segmental lordosis is required, the probability of developing contralateral radiculopathy is increased and caution from the surgeon is needed.

• Nutrition Research and Practice
• /
• v.5 no.3
• /
• pp.266-274
• /
• 2011

Accurate assessment of nutrient adequacy of a population should be based on usual intake distribution of that population. This study was conducted to adjust usual nutrient intake distributions of a single 24-hour recall in 2001 Korean National Health and Nutrition Surveys (KNHNS) in order to determine the magnitude of limitations inherent to a single 24-hour recall in assessing nutrient intakes of a population. Of 9,960 individuals who provided one 24-hour recall in 2001 KNHNS, 3,976 subjects provided an additional one-day 24-hour recall in 2002 Korean National Nutrition Survey by Season (KNNSS). To adjust for usual intake distribution, we estimated within-individual variations derived from 2001 KNHNS and 2002 KNNSS using the Iowa State University method. Nutritionally at risk population was assessed in reference to the Dietary Reference Intakes for Koreans (KDRIs). The Korean Estimated Average Requirement (Korean EAR) cut-point was applied to estimate the prevalence of inadequate nutrient intakes except for iron intakes, which were assessed using the probability approach. The estimated proportions below Korean EAR for calcium, riboflavin, and iron were 73%, 41%, and 24% from usual intake distribution and 70%, 51%, and 39% from one-day intake distribution, respectively. The estimated proportion of sodium intakes over the Intake Goal of 2,000 mg/day was 100% of the population after adjustment. The energy proportion from protein was within Korean Acceptable Macronutrient Distribution Ranges (Korean AMDR), whereas that of carbohydrate was higher than the upper limit and that of fat was below the lower limit in the subjects aged 30 years or older. According to these results, the prevalence of nutritional inadequacy and excess intake is over-estimated in Korea unless usual intake distributions are adjusted for one-day intakes of most nutrients.

• Nutrition Research and Practice
• /
• v.11 no.3
• /
• pp.240-246
• /
• 2017

BACKGROUND/OBJECTIVES: Folic acid supplementation before pregnancy is known to significantly reduce the risk of having a baby with neural tube defects (NTDs). Therefore, it is important for women to be aware of the effects of folic acid supplementation before pregnancy. The purpose of this study was to investigate the awareness and preconceptional use of folic acid and to assess the current knowledge about folic acid among low-income pregnant women in Korea. SUBJECTS/METHODS: A questionnaire survey was conducted in 2012. Five hundred pregnant women were selected from the waiting list for the Nutriplus program implemented in public health centers using a multistage clustered probability sampling design. Data from 439 women were analyzed after excluding ones with incomplete answers. RESULTS: Among women who responded to the questionnaire, 65.6% had heard of folic acid before pregnancy, and 26.4% reported on the preconceptional use of folic acid. Women with a university degree or higher education were more likely to be aware of folic acid and to take folic acid in the preconception period. In a multivariate logistic regression, when age, education level, household income, employment status, gravidity, parity, and folic acid awareness were included in the model, folic acid awareness was a strong predictor of preconceptional folic acid use. As of interview, 85.4% and 77.7% of women were aware of the NTD-preventive role of folic acid and the appropriate time to take folic acid, respectively. The main sources of information on folic acid were healthcare professionals (41.2%), friends and family members (31.2%), and the media (26.5%). CONCLUSIONS: Our results suggest that public health strategies are needed to increase the preconceptional use of folic acid among Korean women.

• Journal of Korean Society for Atmospheric Environment
• /
• v.32 no.5
• /
• pp.457-468
• /
• 2016

Traffic-related air pollutants and particulates from diesel exhaust cause for increasing respiratory health problem. Recent epidemiologic studies have reported adverse effects of urban air pollution on various aspects of respiratory health. Bus or truck terminal workers have high probability of exposure to diesel exhaust particle than general office worker. This study was designed to evaluate the relationship between pulmonary function of people who working at the high-density area of diesel vehicles and pulmonary function of people who working at general office in Seoul. So, this study explored the effects on people with exposure to diesel traffic or exposure to diesel traffic, through the pulmonary function test (PFT). There were significant difference in Forced Vital Capacity (FVC) and Forced Expiratory Volume in 1 second ($FEV_1$) between high-exposure group and control. High-exposure to diesel particle were increased risk of reduction in pulmonary function in this study. These results provide the necessity additional research that manage people who working at the high-density area of diesel vehicles.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.43 no.5
• /
• pp.413-421
• /
• 2015

Since the first Cubesat was launched in 2003, there have been more than 230 Cubesats launched so far. Due to their small size and lightweight, Cubesats were launched by utilizing the empty space of regular launch vehicle. However, this launch method has a weakness that has been easily affecting by the schedule of major payloads. As a new solution to this problem, it has been proposed that a robot arm installed on ISS would be used to launch Cubesats. The orbits of Cubesat deployed from the ISS in various angles and directions are analyzed in this paper. We also analyze the possibility of collision between the Cubesat and ISS within the operational orbit of the CubeSat and eventually calculate the optimal angle of a robot arm, which maximizes the lifetime of Cubesat and minimizes the risk of collision between the Cubesat and ISS.

• Structural Engineering and Mechanics
• /
• v.17 no.3_4
• /
• pp.527-537
• /
• 2004

Consequence-Based Engineering (CBE) is a new paradigm proposed by the Mid-America Earthquake Center (MAE) to guide evaluation and rehabilitation of building structures and networks in areas of low probability - high consequence earthquakes such as the central region of the U.S. The principal objective of CBE is to minimize consequences by prescribing appropriate intervention procedures for a broad range of structures and systems, in consultation with key decision makers. One possible intervention option for rehabilitating unreinforced masonry (URM) buildings, widely used for essential facilities in Mid-America, is passive energy dissipation (PED). After the CBE process is described, its application in the rehabilitation of vulnerable URM building construction in Mid-America is illustrated through the use of PED devices attached to flexible timber floor diaphragms. It is shown that PED's can be applied to URM buildings in situations where floor diaphragm flexibility can be controlled to reduce both out-of-plane and in-plane wall responses and damage. Reductions as high as 48% in roof displacement and acceleration can be achieved as demonstrated in studies reported below.

• Asian Pacific Journal of Cancer Prevention
• /
• v.17 no.2
• /
• pp.867-872
• /
• 2016

Background: Esophageal cancer is one of the most serious malignancies. Due to the aggressive nature of this cancer, the prognosis is poor. A network meta-analysis with simultaneous comparison of multiple treatments can help determine better treatment options that have higher effects on overall survival of patients with lower adverse events. The aim of this review is to simultaneously compare efficacy and adverse events of treatment interventions for esophageal cancer. Materials and Methods: In this review, only randomized control trials (RCT) will be considered for network meta-analysis. All international electronic databases including Medline, Web of Sciences, Scopus, Cochran's library, EMBASE and Cancerlit will be searched to find randomized control trials which compared two or more treatment interventions for esophageal cancer. A network plot will be drawn for visual representation of all available treatment interventions. Bayesian approach will be used to combine the direct and indirect evidence. Treatment effects (e.g. hazard ratio for time to event outcomes, risk ratio for binary outcomes, and rate ratio for count outcomes with 95% credible interval) will be reported. Moreover, cumulative probability of the treatment ranks will be reported using the surface under the cumulative ranking (SUCRA) graphs. Consistency assumption will be assessed by the loop-specific and design-by-treatment interaction approaches. Conclusions: The results of this study may be helpful for the patients, clinicians and health policy makers in selecting treatments that have the best effect on survival and lowest adverse events.

• Journal of Biomedical Engineering Research
• /
• v.38 no.3
• /
• pp.123-128
• /
• 2017

Background and aims: The KCNQ1 S140G mutation involved in $I_{ks}$ channel is a typical gene mutation affecting atrial fibrillation. However, despite the possibility that the S140G gene mutation may affect not only atrial but also ventricular action potential shape and ventricular responses, there is a lack of research on the relationship between this mutation and ventricular fibrillation. Therefore, in this study, we analyzed the correlation and the influence of the KCNQ1 S140G mutant gene on ventricular fibrillation through computer simulation studies. Method: This study simulated a 3-dimensional ventricular model of the wild type(WT) and the S140G mutant conditions. It was performed by dividing into normal sinus rhythm simulation and reentrant wave propagation simulation. For the sinus rhythm, a ventricular model with Purkinje fiber was used. For the reentrant propagation simulation, a ventricular model was used to confirm the occurrence of spiral wave using S1-S2 protocol. Results: The result showed that 41% shortening of action potential duration(APD) was observed due to augmented $I_{ks}$ current in S140G mutation group. The shortened APD contributed to reduce wavelength 39% in sinus rhythm simulation. The shortened wavelength in cardiac tissue allowed re-entrant circuits to form and increased the probability of sustaining ventricular fibrillation, while ventricular electrical propagation with normal wavelength(20.8 cm in wild type) are unlikely to initiate re-entry. Conclusion: In conclusion, KCNQ1 S140G mutation can reduce the threshold of the re-entrant wave substrate in ventricular cells, increasing the spatial vulnerability of tissue and the sensitivity of the fibrillation. That is, S140G mutation can induce ventricular fibrillation easily. It means that S140G mutant can increase the risk of arrhythmias such as cardiac arrest due to heart failure.

• Quality Improvement in Health Care
• /
• v.7 no.2
• /
• pp.218-228
• /
• 2000

Background : Among 'structure', 'process' and 'outcome' approaches, outcome evaluation is considered as the most direct and best approach to assess the quality of health care providers. Risk-adjustment is an essential method to compare outcome across providers. This study has aims to judge performance of hospitals by severity adjusted mortality rates of coronary artery bypass graft (CABG) surgery. Methods : Medical records of 584 patients who got the CABG surgery in 6 general hospitals during 1996 and 1997 were reviewed by trained nurses. The MedisGroups was used to quantify severity of patients. The predictive probability of death was calculated for each patient in the sample from a multivariate logistic regression model including the severity score, age and sex. For evaluation of hospital performance, we calculated ratio of observed number to expected number of deaths and z score [(observed number of deaths - expected number of deaths)/square root of the variance in the number of deaths], and compared observed mortality rate with confidence interval of adjusted mortality rate for each hospital. Results : The overall in-hospital mortality was 7.0%, ranged from 2.7% to 15.7% by hospital. After severity adjustment the mortality by hospital was from 2.7% to 10.7%. One hospital with poor performance was distinctly divided from others with good performance. Conclusion : In conclusion, severity-adjusted mortality rate of CABG surgery might be applied as an indicator for hospital performance evaluation in Korea. But more pilot studies and improvement of methodologies has to be done to use it as quality indicator.