1.Assessing the impact of recombination on the estimation of isolation-with-migration models using genomic data: a simulation study
Genomics & Informatics 2023;21(2):e27-
Recombination events complicate the evolutionary history of populations and species and have a significant impact on the inference of isolation-with-migration (IM) models. However, several existing methods have been developed, assuming no recombination within a locus and free recombination between loci. In this study, we investigated the effect of recombination on the estimation of IM models using genomic data. We conducted a simulation study to evaluate the consistency of the parameter estimators with up to 1,000 loci and analyze true gene trees to examine the sources of errors in estimating the IM model parameters. The results showed that the presence of recombination led to biased estimates of the IM model parameters, with population sizes being more overestimated and migration rates being more underestimated as the number of loci increased. The magnitude of the biases tended to increase with the recombination rates when using 100 or more loci. On the other hand, the estimation of splitting times remained consistent as the number of loci increased. In the absence of recombination, the estimators of the IM model parameters remained consistent.
2.Recent advances in Bayesian inference of isolation-with-migration models
Genomics & Informatics 2019;17(4):37-
Isolation-with-migration (IM) models have become popular for explaining population divergence in the presence of migrations. Bayesian methods are commonly used to estimate IM models, but they are limited to small data analysis or simple model inference. Recently three methods, IMa3, MIST, and AIM, resolved these limitations. Here, we describe the major problems addressed by these three software and compare differences among their inference methods, despite their use of the same standard likelihood function.
Bayes Theorem
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Gene Flow
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Likelihood Functions
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Phylogeny
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Statistics as Topic
3.Recent advances in Bayesian inference of isolation-with-migration models
Genomics & Informatics 2019;17(4):e37-
Isolation-with-migration (IM) models have become popular for explaining population divergence in the presence of migrations. Bayesian methods are commonly used to estimate IM models, but they are limited to small data analysis or simple model inference. Recently three methods, IMa3, MIST, and AIM, resolved these limitations. Here, we describe the major problems addressed by these three software and compare differences among their inference methods, despite their use of the same standard likelihood function.
4.Nurses’ Experiences of Patients’ Safety Accidents
Yujin HUR ; Miha CHUNG ; Jinyoung LEE
Korean Journal of Rehabilitation Nursing 2021;24(2):131-142
Purpose:
This study aimed to understand the meaning of the nurses’experiences of patients’ safety accident.
Methods:
This study is qualitative research using Giorgi’s phenomenological methodology to identify themes of the nurses’experiences of patients’safety accident. The research question was “What is the essential meaning of the nurses’experiences of patients’self-extubating?” Data were collected from the individual in-depth interview from November to December 2017. Seven clinical nurses working in intensive care units were purposely selected.
Results:
The results showed that 6 essential themes and 13 theme clusters were derived. The essential themes of nurses’ experiences were as follows: ‘Fear of unexpected situations’, ‘Guilt for having a safety accident’, ‘Regret about the cause of the accident’, ‘The conflict between patient human rights and adherence to patient safety principles’, ‘Daunted by the blame of others and feelings of guilt’, ‘Attention is paid to accident prevention practices’.
Conclusion
It is necessary to manage post-processing management of incidents and nurses’trauma.
5.The effect of missing levels of nesting in multilevel analysis
Genomics & Informatics 2022;20(3):e34-
Multilevel analysis is an appropriate and powerful tool for analyzing hierarchical structure data widely applied from public health to genomic data. In practice, however, we may lose the information on multiple nesting levels in the multilevel analysis since data may fail to capture all levels of hierarchy, or the top or intermediate levels of hierarchy are ignored in the analysis. In this study, we consider a multilevel linear mixed effect model (LMM) with single imputation that can involve all data hierarchy levels in the presence of missing top or intermediate-level clusters. We evaluate and compare the performance of a multilevel LMM with single imputation with other models ignoring the data hierarchy or missing intermediate-level clusters. To this end, we applied a multilevel LMM with single imputation and other models to hierarchically structured cohort data with some intermediate levels missing and to simulated data with various cluster sizes and missing rates of intermediate-level clusters. A thorough simulation study demonstrated that an LMM with single imputation estimates fixed coefficients and variance components of a multilevel model more accurately than other models ignoring data hierarchy or missing clusters in terms of mean squared error and coverage probability. In particular, when models ignoring data hierarchy or missing clusters were applied, the variance components of random effects were overestimated. We observed similar results from the analysis of hierarchically structured cohort data.
6.The Effects of Digital Literacy and Health Empowerment on Elders' Communication with Doctors:Focusing on Moderating Effect of Health Beliefs
Soontae AN ; Yujin LIM ; Soondool CHUNG
Journal of Korean Academy of Community Health Nursing 2022;33(1):53-62
Purpose:
This study explored the effects of the elderly group's digital literacy and health empowerment on communication with doctors, considering moderating effect of health beliefs about chronic diseases.
Methods:
A one-on-one interview survey was conducted with 500 older adults in South Korea. The main variables were digital literacy, health empowerment, communication with doctors, and health belief of chronic diseases.
Results:
The interaction effect between health empowerment and susceptibility, and health empowerment and perceived barrier were significant.
Conclusion
Communication with doctors greatly increased when the elders had high levels of health empowerment and low levels of susceptibility. Also, communication with doctors greatly increased when the elders had high levels of health empowerment and low levels of perceived barriers.
7.Assault-related Factors and Trauma-related Cognitions Associated with Post-traumatic Stress Symptoms in High-distress and Low-distress Korean Female Victims of Sexual Assault
Kyoung Min SHIN ; Yujin KIM ; Young-Ki CHUNG ; Hyoung Yoon CHANG
Journal of Korean Medical Science 2020;35(19):e144-
Background:
Information about the factors involved in the progress of both high distressed and low distressed victims in the early days after a sexual assault are needed to provide effective intervention for victims of sexual assault. In this study, we examined the relationship among posttraumatic stress disorder (PTSD) symptoms, assault-related factors and trauma-related cognitions in Korean female victims of sexual assault.
Methods:
For this study, we retrospectively investigated the records of 94 female victims from the Sunflower Center for Women and Children Victims of Violence at the Ajou University Hospital in Korea. Demographic characteristics and the features of the sexual assault, post-traumatic stress symptoms, and trauma-related cognition were obtained from data recorded at the initial assessment. One month after the initial assessment, victims were contacted by telephone and their PTSD symptom severity was re-evaluated. The sample of 94 participants were divided into two groups depending on the PTSD symptom scale scores at initial assessment: High-distress group and Low-distress group.
Results:
Repeated-measured analyses of variance revealed that the high-distress group showed a decrease in PTSD symptom severity over the month, while the low-distress group did not show significant change of PTSD symptom severity. In correlation analysis, negative thoughts and beliefs about the assault were strongly correlated with PTSD symptom severity one month later in both the low-distress and high-distress groups.
Conclusion
Our results suggest that trauma-related cognitions seem to play an important role in the maintenance of PTSD both of high-distress and low-distress groups, and that effective intervention will need to address these cognitive factors.
8.Differentiated Muscle-derived Stem Cells Attenuate Intimal Hyperplasia after Carotid Balloon Injury in Rat.
In Mok JUNG ; So Rhee HAN ; Keum Hee CHOI ; Yujin KWON ; Taeseung LEE ; Seung Kee MIN ; Yang Jin PARK ; Jung Kee CHUNG ; Jongwon HA ; Sang Joon KIM
Journal of the Korean Surgical Society 2010;79(Suppl 1):S7-S15
PURPOSE: Although progenitor cells may contribute to intimal hyperplasia (IH) after arterial injury, positive contribution of IH is variable with type of injury or cells. This study was designed to examine whether differentiated muscle derived stem cells (MDSC) attenuate IH in rat. METHODS: MDSCs were retrieved using preplate techniques from rat calf muscle and MDSCs (preplate 6th culture fraction, pp6) were exposed to VEGF (50 ng/ml) for endothelial differentiation prior to injection. Male rats were divided into two groups (cell treated vs. control) and underwent carotid balloon injury with 2-Fr catheter. The virus containing Green fluorescent protein (GFP) gene was transfected into cells for monitoring. Cells (5x10(6)) were indwelled into carotid artery for 30 minutes after injury and then blood flow was restored. Arteries were harvested at various intervals (1, 2 and 4 weeks) after injury. The intima to media thickness ratio (IMTR) was calculated with morphometric analysis. RESULTS: Endothelial surface markers such as VE-CADHERIN were strongly expressed on differentiated MDSCs. At 4 weeks after injury, IH was predominantly observed in control group compared to cell treated group. The intensity of GFP was strongly observed at 1 week and declined at 4 weeks in carotid artery wall at MDSC group. CD31(+) endothelial cells were observed at MDSC group compared to control. The mean IMTR in cell treated groups were significantly lower than control at 2 weeks (P=0.005) and 4 weeks (P< or =0.001). CONCLUSION: Our study demonstrates that MDSCs therapy promotes re-endothelialization and leads to attenuation of IH after balloon injury in rat.
Animals
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Antigens, CD
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Arteries
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Cadherins
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Carotid Arteries
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Catheters
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Endothelial Cells
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Humans
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Hyperplasia
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Male
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Muscles
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Rats
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Stem Cells
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Vascular Endothelial Growth Factor A
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Viruses
9.Development and validation of a method for the simultaneous quantification of endogenous steroids metabolized by CYP3A
Yujin LEE ; Woori CHAE ; Seonghae YOON ; Jae-Yong CHUNG ; Joo-Youn CHO
Translational and Clinical Pharmacology 2020;28(2):73-82
Cytochrome P450 (CYP) 3A enzymes, the most important phase 1 drug-metabolizing enzymes, are responsible for 50% of the metabolism of clinically used drugs. CYP3A activity varies widely among individuals, which can affect the probability of adverse drug reactions and drug-drug interactions mediated by the induction or inhibition of the enzyme. Hence, it is important to be able to predict CYP3A activity in individuals to reduce the incidence of unexpected drug responses. To specifically and quickly measure CYP3A activity, we developed method based on gas chromatography interfaced with triple-quadrupole mass spectrometry for the quantification of cortisol, cortisone, 6β-hydroxycortisol, and 6β-hydroxycortisone simultaneously in urine and 4β-hydroxycholesterol in plasma. The results were calculated based on charcoal-stripped steroid-free urine and plasma control samples. The accuracy and precision were 93.18% to 110.0% and 1.96% to 5.34%, respectively. This method was then applied to measure endogenous steroids from urine and plasma samples of healthy Korean males and females. The calibration curves of all analytes showed good linearity with a correlation coefficient (r2) that ranged from 0.9953 to 0.9999. Therefore, this validated method can be used to measure endogenous biomarkers to predict CYP3A activity and might be applicable in the prediction of CYP3A-mediated drug interactions of new drug candidates.
10.Acute Liver Failure Secondary to Hepatic Infiltration of Malignant Melanoma
Yujin LEE ; Jaekwang LEE ; Hyunsoo KIM ; Changkeun PARK ; Jaekwon JUNG ; Daejin KIM ; YunJin CHUNG ; Hanjun RYU
Clinical Endoscopy 2022;55(2):287-291
Acute liver failure due to malignant melanoma is uncommon. We presents a case of acute liver failure secondary to hepatic infiltration of a malignant melanoma. An 86-year-old man was admitted with elevated liver enzymes and an increased lactate dehydrogenase level. His condition progressed to acute liver failure, but the etiology of liver failure was unclear. Esophagogastroduodenoscopy was performed to evaluate dyspepsia, which showed signs indicative of malignant melanoma. Based on the endoscopy findings and elevated liver enzyme levels, liver biopsy was performed to confirm the presence of malignant melanoma. Hepatic infiltration of malignant melanoma was observed histologically. However, massive and diffuse liver metastasis is very rare and difficult to identify on imaging studies. If the etiology of liver failure is unclear, diffuse metastatic melanoma infiltration should be considered as differential diagnosis. Early liver biopsy can help to clarify the diagnosis.