Publications by authors named "Woojoo Lee"

45 Publications

Time-resolved ARPES Determination of a Quasi-Particle Band Gap and Hot Electron Dynamics in Monolayer MoS.

Nano Lett 2021 Sep 23;21(17):7363-7370. Epub 2021 Aug 23.

Department of Physics, The University of Texas at Austin, Austin, Texas 78712, United States.

The electronic structure and dynamics of 2D transition metal dichalcogenide (TMD) monolayers provide important underpinnings both for understanding the many-body physics of electronic quasi-particles and for applications in advanced optoelectronic devices. However, extensive experimental investigations of semiconducting monolayer TMDs have yielded inconsistent results for a key parameter, the quasi-particle band gap (QBG), even for measurements carried out on the same layer and substrate combination. Here, we employ sensitive time- and angle-resolved photoelectron spectroscopy (trARPES) for a high-quality large-area MoS monolayer to capture its momentum-resolved equilibrium and excited-state electronic structure in the weak-excitation limit. For monolayer MoS on graphite, we obtain QBG values of ≈2.10 eV at 80 K and of ≈2.03 eV at 300 K, results well-corroborated by the scanning tunneling spectroscopy (STS) measurements on the same material.
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http://dx.doi.org/10.1021/acs.nanolett.1c02674DOI Listing
September 2021

Hygroscopic properties of particulate matter and effects of their interactions with weather on visibility.

Sci Rep 2021 08 12;11(1):16401. Epub 2021 Aug 12.

School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, 639798, Singapore.

The hygroscopic property of particulate matter (PM) influencing light scattering and absorption is vital for determining visibility and accurate sensing of PM using a low-cost sensor. In this study, we examined the hygroscopic properties of coarse PM (CPM) and fine PM (FPM; PM) and the effects of their interactions with weather factors on visibility. A censored regression model was built to investigate the relationships between CPM and PM concentrations and weather observations. Based on the observed and modeled visibility, we computed the optical hygroscopic growth factor, [Formula: see text], and the hygroscopic mass growth, [Formula: see text], which were applied to PM field measurement using a low-cost PM sensor in two different regions. The results revealed that the CPM and PM concentrations negatively affect visibility according to the weather type, with substantial modulation of the interaction between the relative humidity (RH) and PM. The modeled [Formula: see text] agreed well with the observed [Formula: see text] in the RH range of the haze and mist. Finally, the RH-adjusted PM concentrations based on the visibility-derived hygroscopic mass growth showed the accuracy of the low-cost PM sensor improved. These findings demonstrate that in addition to visibility prediction, relationships between PMs and meteorological variables influence light scattering PM sensing.
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http://dx.doi.org/10.1038/s41598-021-95834-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8361198PMC
August 2021

Epidemiological and spatio-temporal characteristics of COVID-19 in Rwanda.

Glob Epidemiol 2021 Nov 4;3:100058. Epub 2021 Aug 4.

Department of Public Health Science, Seoul National University, Seoul, Republic of Korea.

Background: The coronavirus disease 2019 (COVID-19) has taken millions of lives and disrupted living standards at individual, societal, and worldwide levels, causing serious consequences globally. Understanding its epidemic curve and spatio-temporal dynamics is crucial for the development of effective public health plans and responses and the allocation of resources. Thus, we conducted this study to assess the epidemiological dynamics and spatio-temporal patterns of the COVID-19 pandemic in Rwanda.

Methods: Using the surveillance package in R software version 4.0.2, we implemented endemic-epidemic multivariate time series models for infectious diseases to analyze COVID-19 data reported by Rwanda Biomedical Center under the Ministry of Health from March 15, 2020 to January 15, 2021.

Results: The COVID-19 pandemic occurred in two waves in Rwanda and showed a heterogenous spatial distribution across districts. The Rwandan government responded effectively and efficiently through the implementation of various health measures and intervention policies to drastically reduce the transmission of the disease. Analysis of the three components of the model showed that the most affected districts displayed epidemic components within the area, whereas the effect of epidemic components from spatial neighbors were experienced by the districts that surround the most affected districts. The infection followed the disease endemic trend in other districts.

Conclusion: The epidemiological and spatio-temporal dynamics of COVID-19 in Rwanda show that the implementation of measures and interventions contributed significantly to the decrease in COVID-19 transmission within and between districts. This accentuates the critical call for continued intra- and inter- organization and community engagement nationwide to ensure effective and efficient response to the pandemic.
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http://dx.doi.org/10.1016/j.gloepi.2021.100058DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8333025PMC
November 2021

Joint association of prenatal bisphenol-A and phthalates exposure with risk of atopic dermatitis in 6-month-old infants.

Sci Total Environ 2021 May 24;789:147953. Epub 2021 May 24.

Department of Occupational and Environmental Medicine, College of Medicine, Ewha Womans University, Seoul, Republic of Korea; Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul, Republic of Korea; Ewha Medical Research Institute, College of Medicine, Ewha Womans University, Seoul, Republic of Korea. Electronic address:

Background: Prenatal exposure to bisphenol A (BPA) and phthalates could trigger immune response. Few studies have investigated the association between prenatal BPA and phthalate exposure and atopic dermatitis (AD) in infants.

Objective: We aimed to clarify the joint association of prenatal exposure to BPA and phthalate metabolites with AD incidence in 6-month-old infants.

Methods: We included 413 mother-child pairs from the Mothers and Children's Environmental Health (MOCEH) in a prospective birth cohort study. Maternal urinary BPA, mono-2-ethyl-5-hydroxyhexyl phthalate (MEHHP), mono-2-ethyl-5-oxohexyl phthalate (MEOHP), and mono-n-butyl phthalate (MnBP) concentrations were measured during early and late pregnancy. We applied the Bayesian kernel machine regression (BKMR) with probit regression to estimate the association of BPA and phthalate metabolites with AD incidence after adjusting for potential confounders. Individual association was estimated by differences in predicted probabilities comparing each individual chemical concentration at 75th versus 25th percentiles, while other chemicals were set at their median. Overall joint effect was estimated by differences in predicted probabilities comparing all chemical concentrations at 75th versus 25th percentiles.

Results: Individual effect of MEHHP in late pregnancy was strongly associated with incident AD [Difference: 0.244 (95% credible interval: -0.066, 0.554)] in the model including both early and late exposures. Furthermore, we confirmed overall joint association of urinary BPA and phthalate metabolites during pregnancy with a higher risk of AD [0.347 (0.168, 0.526) for late pregnancy exposure, and 0.307 (0.094, 0.521) for both early and late pregnancy]. Additionally, the joint association was more prominent among girls than that in boys.

Conclusions: The joint association of prenatal exposure to BPA and phthalates could be associated with the incident AD in 6-month-old infants. Further studies are needed to confirm the synergistic effect of BPA and phthalate exposures on AD in children.
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http://dx.doi.org/10.1016/j.scitotenv.2021.147953DOI Listing
May 2021

Effects of Local Anesthetic Volume (Standard Versus Low) on Incidence of Hemidiaphragmatic Paralysis and Analgesic Quality for Ultrasound-Guided Superior Trunk Block After Arthroscopic Shoulder Surgery.

Anesth Analg 2021 11;133(5):1303-1310

From the Department of Anesthesiology and Pain Medicine, Inha University Hospital, Incheon, South Korea.

Background: Relative to interscalene block, superior trunk block (STB) provides comparable analgesia and a reduced risk of hemidiaphragmatic paralysis. However, the incidence of hemidiaphragmatic paralysis remains high when a standard volume (15 mL) of local anesthetic is used. This study aimed to evaluate the effects of local anesthetic volume of STB on the incidence of phrenic nerve palsy, as well as its analgesic efficacy following arthroscopic shoulder surgery.

Methods: Patients scheduled for elective arthroscopic shoulder surgery were randomized to receive ultrasound-guided STB using either 5- or 15-mL 0.5% ropivacaine before general anesthesia. The primary outcome was the incidence of hemidiaphragmatic paralysis at 30 minutes after block. The secondary outcomes were pulmonary function, grade of sensory and motor blockade, pain score, opioid consumption, adverse effects, and satisfaction.

Results: Relative to standard-volume STB, low-volume STB was associated with a lower incidence of hemidiaphragmatic paralysis after block (14.3 [4.8%-30.3%] vs 65.7 [46.8%-80.9%]; difference 51.4% [95% confidence intervals {CIs}, 29.0%-67.1%]; P < .0001) and at the postanesthesia care unit (9.4% vs 50.0%; difference 40.6 [95% CI, 18.9%-57.7%]; P = .0004). Pulmonary function was also better preserved in the low-volume group than in the standard-volume group. The extent of the sensory and motor blocks was significantly different between the groups. Pain-related outcomes, satisfaction, and any adverse events were not significantly different between the groups.

Conclusions: Low-volume STB provided a lower incidence of hemidiaphragmatic paralysis with no significant difference in analgesic efficacy relative to standard-volume STB for arthroscopic shoulder surgery.
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http://dx.doi.org/10.1213/ANE.0000000000005654DOI Listing
November 2021

Machine learning enhances the performance of short and long-term mortality prediction model in non-ST-segment elevation myocardial infarction.

Sci Rep 2021 06 18;11(1):12886. Epub 2021 Jun 18.

Department of Prevention and Management, School of Medicine, Inha University Hospital, Inha University, 27 Inhang-Ro, Jung-Gu, Incheon, Republic of Korea.

Machine learning (ML) has been suggested to improve the performance of prediction models. Nevertheless, research on predicting the risk in patients with acute myocardial infarction (AMI) has been limited and showed inconsistency in the performance of ML models versus traditional models (TMs). This study developed ML-based models (logistic regression with regularization, random forest, support vector machine, and extreme gradient boosting) and compared their performance in predicting the short- and long-term mortality of patients with AMI with those of TMs with comparable predictors. The endpoints were the in-hospital mortality of 14,183 participants and the three- and 12-month mortality in patients who survived at discharge. The performance of the ML models in predicting the mortality of patients with an ST-segment elevation myocardial infarction (STEMI) was comparable to the TMs. In contrast, the areas under the curves (AUC) of the ML models for non-STEMI (NSTEMI) in predicting the in-hospital, 3-month, and 12-month mortality were 0.889, 0.849, and 0.860, respectively, which were superior to the TMs, which had corresponding AUCs of 0.873, 0.795, and 0.808. Overall, the performance of the predictive model could be improved, particularly for long-term mortality in NSTEMI, from the ML algorithm rather than using more clinical predictors.
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http://dx.doi.org/10.1038/s41598-021-92362-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8213755PMC
June 2021

Application of N Descriptors Proposed by the International Association for the Study of Lung Cancer in Clinical Staging.

Radiology 2021 08 1;300(2):450-457. Epub 2021 Jun 1.

From the Department of Radiology (H.S., S.H.Y., Junghoon Kim, Jihang Kim, K.W.L., K.H.L.), Department of Thoracic and Cardiovascular Surgery (K.K.), Division of Pulmonology and Critical Care Medicine, Department of Internal Medicine (C.T.L.), and Department of Pathology and Translational Medicine (J.H.C.), Seoul National University Bundang Hospital, Seoul National University College of Medicine, 82 Gumi-ro 173 Beon-gil, Bundang-gu, Seongnam 13620, Korea; and Departments of Public Health Science, Graduate School of Public Health (W.L.) and Applied Bioengineering, Graduate School of Convergence Science and Technology (S.L.), Seoul National University, Seoul, Korea.

Background Patients with N1 or N2 non-small cell lung cancer exhibit prognostic heterogeneity. To refine the current N staging system, new N stages were proposed by the International Association for the Study of Lung Cancer. However, those proposed new N stages have not been validated. Purpose To evaluate the prognostic performance of the proposed N descriptors for clinical staging. Materials and Methods Participants with non-small cell lung cancer without distant metastasis from January 2010 to December 2014 were retrospectively included. Each patient's clinical N (cN) stage was assigned to one of seven categories (cN0, cN1a, cN1b, cN2a1, cN2a2, cN2b, cN3). The 5-year overall survival rates were estimated with the Kaplan-Meier method. The adjusted hazard ratios (HRs) and their 95% CIs were estimated by using a multivariable Cox proportional hazard model. Ad hoc analyses according to lymph node (LN) size were performed. Results A total of 1271 patients (median age, 66 years; interquartile range, 59-73 years; 812 men) were included. The 5-year overall survival rates were 77.3%, 53.7%, 36.0%, 29.2%, 34.4%, 18.0%, and 12.4% for stages cN0, cN1a, cN1b, cN2a1, cN2a2, cN2b, and cN3, respectively. Patients with cN2b disease had a worse prognosis than patients with cN2a disease (HR, 1.53; 95% CI: 1.06, 2.22; = .02). There was no prognostic difference between cN1b and cN1a (HR, 1.13; 95% CI: 0.61, 2.09; = .71); however, there was a difference between cN1 subgroups when stratified by LN size (≥2 cm; HR, 2.26; 95% CI: 1.16, 4.44; = .02). Within cN2a disease, there were no differences between cN2a1 and cN2a2 (HR, 0.98; 95% CI: 0.61, 1.56; = .93) or between subgroups according to LN size (HR, 0.74; 95% CI: 0.40, 1.37; = .34). Conclusion A survival difference was observed between single- and multistation involvement among cN2 disease. The number of involved lymph node stations in patients with cN1 disease and the presence of skip metastasis in patients with cN2 disease were not associated with survival differences. © RSNA, 2021
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http://dx.doi.org/10.1148/radiol.2021204461DOI Listing
August 2021

Comparison of Thoracic Epidural Access with Lateral Decubitus and Shoulder Rotation Positions for Repeat Thoracic Epidural Blockade.

Pain Physician 2021 05;24(3):E327-E334

Department of Anesthesiology and Pain Medicine, Inha University College of Medicine, Incheon, Republic of Korea.

Background: Shoulder rotation has been shown to increase the acoustic window of ultrasound for thoracic epidural access. However, this effect of shoulder rotation has not yet been confirmed in clinical practice.

Objective: This study aimed to evaluate the effects of shoulder rotation on the thoracic epidural blockade in patients with acute or chronic pain in the thoracic region.

Study Design: Prospective crossover trial.

Setting: Pain clinic of our university in the Republic of Korea.

Methods: Forty patients aged 20 - 80 years with acute or chronic pain in the thoracic region who were scheduled to undergo thoracic epidural blockade more than twice.

Interventions: The patients underwent repeated fluoroscopy-guided thoracic epidural blockade via the paramedian approach in the lateral decubitus position either with or without shoulder rotation.The primary outcome measure was the attempt time to the confirmed spread of contrast. The number of attempts, total procedure time, vertical interpedicular distance, contrast spreading length, and complications were compared between the 2 positions.

Results: The median attempt times in the lateral decubitus and shoulder rotation positions were 138.8 and 132.5 seconds, respectively, and this difference was significant (P = 0.004). Compared with the lateral decubitus position, the shoulder rotation position was also associated with a significantly lower number of attempts (P = 0.03), shorter total procedure time (P < 0.001), and greater vertical interpedicular and contrast spreading distances (P < 0.001 and P = 0.02, respectively).

Limitations: The operator in this study was not blinded to the patient groups. Other researchers observed the operator's procedure and evaluated and recorded the data in an attempt to overcome this bias. However, it was difficult to completely avoid the bias. Second, epidural blockade was performed at various levels (T3-11), and the anatomical features vary among thoracic spine levels.

Conclusions: The study findings demonstrate the clinical benefits of the shoulder rotation position versus the lateral decubitus position in terms of successful epidural access during thoracic epidural blockade using the paramedian approach.
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May 2021

Effect of intravenous dexamethasone on the duration of postoperative analgesia for popliteal sciatic nerve block: a randomized, double-blind, placebo-controlled study.

Korean J Anesthesiol 2021 08 31;74(4):317-324. Epub 2021 Mar 31.

Department of Anesthesiology and Pain Medicine, Inha University School of Medicine, Incheon, Korea.

Background: Intravenous (IV) dexamethasone prolongs the duration of a peripheral nerve block; however, there is little available information about its optimal effective dose. This study aimed to evaluate the effects of three different doses of IV dexamethasone on the duration of postoperative analgesia to determine the optimal effective dose for a sciatic nerve block.

Methods: Patients scheduled for foot and ankle surgery were randomly assigned to receive normal saline or IV dexamethasone (2.5 mg, 5 mg, or 10 mg). An ultrasound-guided popliteal sciatic nerve block was performed using 0.75% ropivacaine (20 ml) before general anesthesia. The duration of postoperative analgesia was the primary outcome, and pain scores, use of rescue analgesia, onset time, adverse effects, and patient satisfaction were assessed as secondary outcomes.

Results: Compared with the control group, the postoperative analgesic duration of the sciatic nerve block was prolonged in groups receiving IV dexamethasone 10 mg (P < 0.001), but not in the groups receiving IV dexamethasone 2.5 mg or 5 mg. The use of rescue analgesics was significantly different among the four groups 24 h postoperatively (P = 0.001) and similar thereafter. However, pain scores were not significantly different among the four groups 24 h postoperatively. There were no statistically significant differences in the other secondary outcomes among the four groups.

Conclusions: This study demonstrated that compared to the controls, only IV dexamethasone 10 mg increased the duration of postoperative analgesia following a sciatic nerve block for foot and ankle surgery without the occurrence of adverse events.
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http://dx.doi.org/10.4097/kja.20640DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8342835PMC
August 2021

Prenatal heavy metal exposures and atopic dermatitis with gender difference in 6-month-old infants using multipollutant analysis.

Environ Res 2021 04 16;195:110865. Epub 2021 Feb 16.

Occupational and Environmental Medicine, College of Medicine, Ewha Womans University, Seoul, Republic of Korea; Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul, Republic of Korea; Ewha Medical Research Institute, College of Medicine, Ewha Womans University, Seoul, Republic of Korea. Electronic address:

Background: Prenatal exposure to heavy metals during critical developmental phases has been implicated in allergic phenotypes. However, few studies have been conducted on the gender-specific association of prenatal heavy metal exposure with atopic dermatitis (AD) in infants.

Objective: To examine the gender-specific association of prenatal exposure to multiple heavy metals with AD incidence in 6-month-old infants using data from the Mothers and Children's Environmental Health (MOCEH).

Methods: We evaluated 738 mother-child pairs from the MOCEH study, an ongoing prospective birth cohort. The concentrations of three heavy metals (lead, mercury and cadmium) in maternal blood samples were measured during early and late pregnancy. Each quartile of heavy metal concentration was used to consider the possible nonlinear association with AD. For assessing the multi-pollutant model, we constructed the multivariate regression model including all three heavy metals at both early and late pregnancy. Further, the group Lasso model was used to perform the variable selection with categorized exposures and assess the effect of multiple pollutants including their pairwise interactions.

Results: A total of 200 incident cases of AD were diagnosed in 6-month-old infants. In the multivariate regression model of the boy group, adjusted odds ratios comparing the second, third and fourth quartile of lead exposure in boys with the first quartile were 1.83 (95% CI: 1.00, 3.38), 1.04 (0.91, 3.32) and 2.40 (1.18, 4.90), respectively. However, the only second quartile of lead exposure compared to first quartile was significantly associated with AD in girls. In addition, the results of the group Lasso model were similar with the results of multivariate regression model.

Conclusion: The results suggest that lead exposure in late pregnancy increases risk of AD in 6-month-old boys although the strength of association is weak. Further studies are needed to confirm the susceptibility window and gender differences in lead-induced AD.
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http://dx.doi.org/10.1016/j.envres.2021.110865DOI Listing
April 2021

Risk of Hematologic Malignant Neoplasms From Abdominopelvic Computed Tomographic Radiation in Patients Who Underwent Appendectomy.

JAMA Surg 2021 Apr;156(4):343-351

Department of Radiology, Seoul National University Bundang Hospital, Gyeonggi-do, Korea.

Importance: Whether computed tomography (CT) radiation is truly carcinogenic remains controversial. Large epidemiological studies that purportedly showed an association between CT radiation and carcinogenesis were limited by confounding by indication and reverse causation, because the reasons for CT examination were unknown.

Objective: To measure the risk of hematologic malignant neoplasms associated with perioperative abdominopelvic CT radiation among patients who underwent appendectomy for acute appendicitis.

Design, Setting, And Participants: This nationwide population-based cohort study used the National Health Insurance Service claims database in South Korea to assess 825 820 patients who underwent appendectomy for appendicitis from January 1, 2005, to December 31, 2015, and had no underlying risk factors for cancer. Patients were divided into CT-exposed (n = 306 727) or CT-unexposed (n = 519 093) groups. The study was terminated on December 31, 2017, and data were analyzed from October 30, 2018, to September 27, 2020.

Exposures: Perioperative abdominopelvic CT examination from 7 days before to 7 days after appendectomy.

Main Outcomes And Measures: The primary outcome was the incidence rate ratio (IRR) of hematologic malignant neoplasms for both groups. The secondary outcomes were IRR of abdominopelvic organ cancers and IRR of all cancers. The lag period was 2 years for the primary outcome and 5 years for secondary outcomes. The IRRs were calculated using Poisson regression models with adjustment for age and sex.

Results: Among the study population of 825 820 patients (52.9% male; median age, 28 [interquartile range, 15-41] years), hematologic malignant neoplasms developed in 323 patients in the CT-exposed group during 1 486 518 person-years and 500 patients in the CT-unexposed group during 3 422 059 person-years. For all hematologic malignant neoplasms, the IRR for the CT-exposed vs CT-unexposed group was 1.26 (95% CI, 1.09-1.45; P = .002). In terms of individual categories of hematologic malignant neoplasms, the CT-exposed group had an elevated risk only for leukemia (IRR, 1.40 [98.75% CI, 1.04-1.87, adjusted by Bonferroni correction]; P = .005). There was no between-group difference in incidence rate of abdominopelvic organ cancers (IRR, 1.07 [95% CI, 1.00-1.15]; P = .06) and that of all cancers (IRR, 1.04 [95% CI, 0.99-1.09]; P = .14).

Conclusions And Relevance: This study controlled for reverse causation bias by defining the reasons for CT scan, and findings suggest that abdominopelvic CT radiation is associated with a higher incidence of hematologic malignant neoplasms. Efforts should be continued for judicious use of CT examinations.
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http://dx.doi.org/10.1001/jamasurg.2020.6357DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8047726PMC
April 2021

Effectiveness of bystander cardiopulmonary resuscitation in improving the survival and neurological recovery of patients with out-of-hospital cardiac arrest: A nationwide patient cohort study.

PLoS One 2020 16;15(12):e0243757. Epub 2020 Dec 16.

Department of Prevention and Management, Inha University Hospital, School of Medicine, Inha University, Incheon, South Korea.

Introduction: Few studies have focused on enhancing causality and yielding unbiased estimates on the effectiveness of bystander cardiopulmonary resuscitation (BCPR) on the outcomes of out-of-hospital cardiac arrest (OHCA) in a real-world setting. Therefore, this study evaluated the effect of BCPR on the outcomes of OHCA and its differences according to the characteristics of OHCA.

Methods: This study enrolled all patients with OHCA of cardiac etiology treated by emergency medical services (EMS) in Korea from 2012 to 2015. The endpoints were survival and neurological recovery at discharge, and the main exposure was BCPR conducted by a layperson. The effect of BCPR was analyzed after adjusting for confounders, determined using a directed acyclic graph, by inverse probability of treatment weighting (IPTW) and model-based standardization (STR). Moreover, differences in subgroups and time trends were evaluated.

Results: Among 10,505 eligible patients after excluding those with missing data on BCPR, 7,721 patients received BCPR, accounting for 74.3% of EMS-treated OHCA patients. BCPR increased the odds of survival and good neurological recovery at discharge by 1.67- (95% confidence interval (CI): 1.44-1.93) and 1.93- (95% CI: 1.56-2.39) fold, respectively, in the IPTW analysis. These findings were comparable to those obtained with STR. The odds ratios were 2.39 (95% CI: 1.91-2.94) and 2.70 (95% CI: 1.94-3.41), respectively, in the sensitivity analysis of the missing BCPR information considering confounders and the outcome variable. However, the effect of qualified BCPR was not evenly distributed, and it did not increase with time. BCPR was likely to be more effective in male patients aged <65 years, those who experienced an OHCA in a private place or non-capital region, and those with shockable rhythm at the scene.

Conclusion: Based on data from a nationwide registry, the estimated effect of BCPR on survival and neurological recovery was moderate and did not improve from 2012 to 2015.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0243757PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7744051PMC
January 2021

The Association between Community Water Fluoridation and Bone Diseases: A Natural Experiment in Cheongju, Korea.

Int J Environ Res Public Health 2020 12 9;17(24). Epub 2020 Dec 9.

Department of Public Health Sciences, Graduate School of Public Health, Seoul National University, Seoul 08826, Korea.

The present study aimed to investigate the association between bone diseases and community water fluoridation (CWF). An ecological study with a natural experiment design was conducted in Cheongju, South Korea, from 1 January 2004 to 31 December 2013. The community water fluoridation program was implemented in Cheongju and divided into CWF and non-CWF areas. To observe adverse health effects related to bone diseases, we conducted a spatio-temporal analysis of the prevalence of hip fracture, osteoporosis, and bone cancer in residents who have lived in CWF and non-CWF areas using National Health Insurance Service data. First, we used standardized incidence ratios to estimate the disease risk. Second, the hierarchical Bayesian Poisson spatio-temporal regression model was used to investigate the association between the selected bone diseases and CWF considering space and time interaction. The method for Bayesian estimation was based on the R-integrated nested Laplace approximation (INLA). Comparing the CWF area with the non-CWF area, there was no clear evidence that exposure to CWF increased health risks at the town level in Cheongju since CWF was terminated after 2004. The posterior relative risks (RR) of hip fracture was 0.95 (95% confidence intervals 0.87, 1.05) and osteoporosis was 0.94 (0.87, 1.02). The RR in bone cancer was a little high because the sample size very small compared to the other bone diseases (RR = 1.20 (0.89, 1.61)). The relative risk of selected bone diseases (hip fractures, osteoporosis, and bone cancer) increased over time but did not increase in the CWF area compared to non-CWF areas. CWF has been used to reduce dental caries in all population groups and is known for its cost-effectiveness. These findings suggest that CWF is not associated with adverse health risks related to bone diseases. This study provides scientific evidence based on a natural experiment design. It is necessary to continue research on the well-designed epidemiological studies and develop public health prevention programs to help in make suitable polices.
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http://dx.doi.org/10.3390/ijerph17249170DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7764285PMC
December 2020

Occurrence of metabolic diseases associated with antipsychotic use among Korean patients with schizophrenia.

Int J Clin Pharmacol Ther 2021 Apr;59(4):298-307

Objective: Metabolic side effects of antipsychotics significantly affect adherence to medication. We aimed to identify factors associated with the occurrence of metabolic diseases among Korean patients with schizophrenia (SCZ) from the national health insurance system database. We evaluated the frequency of antidiabetic and antihyperlipidemic use after diagnosis of SCZ according to typical or atypical antipsychotic use.

Materials And Methods: Among the 43,800 patients diagnosed with SCZ between 2008 and 2012, 29,591 patients who had no metabolic diseases before the diagnosis were included in the analysis to investigate the occurrence of metabolic diseases associated with antipsychotic use. The associations between the development of metabolic diseases and patient characteristics were evaluated using logistic regression analysis.

Results: Use of both typical and atypical antipsychotics (multivariate-adjusted odds ratio (OR), 1.2513; 95% confidence interval (CI), 1.0953 - 1.4294) was associated with higher incidence of metabolic diseases than without their use. Among the atypical antipsychotics, use of clozapine (multivariate-adjusted OR, 1.1959; 95% CI, 1.0086 - 1.4179) and quetiapine (multivariate-adjusted OR, 1.1284; 95% CI, 1.0446 - 1.2189) showed higher incidence of metabolic diseases compared to that without their use. Among the patients using ≥ 1 type of antidiabetic or antihyperlipidemic agents within 6 years after diagnosis of SCZ, the proportion of patients using only atypical antipsychotics was greater than those using only typical antipsychotics.

Conclusion: The use of both typical and atypical antipsychotics, and clozapine and quetiapine treatment, may be associated with the occurrence of metabolic diseases in patients with SCZ. Additional prospective studies with accurate dosage information are needed to validate our findings.
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http://dx.doi.org/10.5414/CP203814DOI Listing
April 2021

Dopamine dysregulation in psychotic relapse after antipsychotic discontinuation: an [F]DOPA and [C]raclopride PET study in first-episode psychosis.

Mol Psychiatry 2021 Jul 14;26(7):3476-3488. Epub 2020 Sep 14.

Department of Psychiatry, Seoul National University Bundang Hospital, Gyeonggi-do, Republic of Korea.

Although antipsychotic drugs are effective for relieving the psychotic symptoms of first-episode psychosis (FEP), psychotic relapse is common during the course of the illness. While some FEPs remain remitted even without medication, antipsychotic discontinuation is regarded as the most common risk factor for the relapse. Considering the actions of antipsychotic drugs on presynaptic and postsynaptic dopamine dysregulation, this study evaluated possible mechanisms underlying relapse after antipsychotic discontinuation. Twenty five FEPs who were clinically stable and 14 matched healthy controls were enrolled. Striatal dopamine activity was assessed as K value using [F]DOPA PET before and 6 weeks after antipsychotic discontinuation. The D2/3 receptor availability was measured as BP using [C]raclopride PET after antipsychotic discontinuation. Healthy controls also underwent PET scans according to the corresponding schedule of the patients. Patients were monitored for psychotic relapse during 12 weeks after antipsychotic discontinuation. 40% of the patients showed psychotic relapse after antipsychotic discontinuation. The change in K value over time significantly differed between relapsed, non-relapsed patients and healthy controls (Week*Group: F = 4.827, df = 2,253.193, p = 0.009). In relapsed patients, a significant correlation was found between baseline striatal K values and time to relapse after antipsychotic discontinuation (R = 0.518, p = 0.018). BP were not significantly different between relapsed, non-relapsed patients and healthy controls (F = 1.402, df = 2,32.000, p = 0.261). These results suggest that dysfunctional dopamine autoregulation might precipitate psychotic relapse after antipsychotic discontinuation in FEP. This finding could be used for developing a strategy for the prevention of psychotic relapse related to antipsychotic discontinuation.
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http://dx.doi.org/10.1038/s41380-020-00879-0DOI Listing
July 2021

Long-Term Monitoring of Noxious Bacteria for Construction of Assurance Management System of Water Resources in Natural Status of the Republic of Korea.

J Microbiol Biotechnol 2020 Oct;30(10):1516-1524

Department of Life Science, Graduate School, Kyonggi University, Suwon 16227, Republic of Korea.

Climate change is expected to affect not only availability and quality of water, the valuable resource of human life on Earth, but also ultimately public health issue. A six-year monitoring (total 20 times) of O157, , , , , and was conducted at five raw water sampling sites including two lakes, Hyundo region (Geum River) and two locations near Water Intake Plants of Han River (Guui region) and Nakdong River (Moolgeum region). A total 100 samples of 40 L water were tested. Most of the targeted bacteria were found in 77% of the samples and at least one of the target bacteria was detected (65%). Among all the detected bacteria, O157 were the most prevalent with a detection frequency of 22%, while was the least prevalent with a detection frequency of 2%. Nearly all the bacteria (except for ) were present in samples from Lake Soyang, Lake Juam, and the Moolgeum region in Nakdong River, while was detected in those from the Guui region in Han River. During the six-year sampling period, individual targeted noxious bacteria in water samples exhibited seasonal patterns in their occurrence that were different from the indicator bacteria levels in the water samples. The fact that they were detected in the five Korea's representative water environments make it necessary to establish the chemical and biological analysis for noxious bacteria and sophisticated management systems in response to climate change.
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http://dx.doi.org/10.4014/jmb.2004.04064DOI Listing
October 2020

On the finite sample distribution of the likelihood ratio statistic for testing heterogeneity in meta-analysis.

Biom J 2020 Aug 5. Epub 2020 Aug 5.

Department of Public Health Science, Graduate School of Public Health, Seoul National University, Seoul, South Korea.

In meta-analysis, hypothesis testing is one of the commonly used approaches for assessing whether heterogeneity exists in effects between studies. The literature concluded that the Q-statistic is clearly the best choice and criticized the performance of the likelihood ratio test in terms of the type I error control and power. However, all the criticism for the likelihood ratio test is based on the use of a mixture of two chi-square distributions with 0 and 1 degrees of freedom, which is justified only asymptotically. In this study, we develop a novel method to derive the finite sample distribution of the likelihood ratio test and restricted likelihood ratio test statistics for testing the zero variance component in the random effects model for meta-analysis. We also extend this result to the heterogeneity test when metaregression is applied. A numerical study shows that the proposed statistics have superior performance to the Q-statistic, especially when the number of studies collected for meta-analysis is small to moderate.
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http://dx.doi.org/10.1002/bimj.201900400DOI Listing
August 2020

Profiles of histidine-rich glycoprotein associate with age and risk of all-cause mortality.

Life Sci Alliance 2020 10 31;3(10). Epub 2020 Jul 31.

Department of Protein Science, Science for Life Laboratory, KTH-Royal Institute of Technology, Solna, Sweden

Despite recognizing aging as a common risk factor of many human diseases, little is known about its molecular traits. To identify age-associated proteins circulating in human blood, we screened 156 individuals aged 50-92 using exploratory and multiplexed affinity proteomics assays. Profiling eight additional study sets (N = 3,987), performing antibody validation, and conducting a meta-analysis revealed a consistent age association ( = 6.61 × 10) for circulating histidine-rich glycoprotein (HRG). Sequence variants of HRG influenced how the protein was recognized in the immunoassays. Indeed, only the HRG profiles affected by rs9898 were associated with age and predicted the risk of mortality (HR = 1.25 per SD; 95% CI = 1.12-1.39; = 6.45 × 10) during a follow-up period of 8.5 yr after blood sampling (IQR = 7.7-9.3 yr). Our affinity proteomics analysis found associations between the particular molecular traits of circulating HRG with age and all-cause mortality. The distinct profiles of this multipurpose protein could serve as an accessible and informative indicator of the physiological processes related to biological aging.
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http://dx.doi.org/10.26508/lsa.202000817DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7409555PMC
October 2020

Deep Learning-based Automatic Detection Algorithm for Reducing Overlooked Lung Cancers on Chest Radiographs.

Radiology 2020 09 21;296(3):652-661. Epub 2020 Jul 21.

From the Department of Radiology, Seoul National University Bundang Hospital, 300 Gumi-dong, Bundang-gu, Seongnam-si, Gyeonggi-do 13620, Korea (S.J., H.S., Junghoon Kim, Jihang Kim, K.W.L., S.S.L., K.H.L.); Department of Radiology, Konkuk University Medical Center, Seoul, Korea (Y.J.S.); Seoul National University College of Medicine, Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea (K.W.L.); Department of Public Health Science, Graduate School of Public Health, Seoul National University, Seoul, Korea (W.L.); and Program in Biomedical Radiation Sciences, Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, Korea (S.L.).

Background It is uncertain whether a deep learning-based automatic detection algorithm (DLAD) for identifying malignant nodules on chest radiographs will help diagnose lung cancers. Purpose To evaluate the efficacy of using a DLAD in observer performance for the detection of lung cancers on chest radiographs. Materials and Methods Among patients diagnosed with lung cancers between January 2010 and December 2014, 117 patients (median age, 69 years; interquartile range [IQR], 64-74 years; 57 women) were retrospectively identified in whom lung cancers were visible on previous chest radiographs. For the healthy control group, 234 patients (median age, 58 years; IQR, 48-68 years; 123 women) with normal chest radiographs were randomly selected. Nine observers reviewed each chest radiograph, with and without a DLAD. They detected potential lung cancers and determined whether they would recommend chest CT for follow-up. Observer performance was compared with use of the area under the alternative free-response receiver operating characteristic curve (AUC), sensitivity, and rates of chest CT recommendation. Results In total, 105 of the 117 patients had lung cancers that were overlooked on their original radiographs. The average AUC for all observers significantly rose from 0.67 (95% confidence interval [CI]: 0.62, 0.72) without a DLAD to 0.76 (95% CI: 0.71, 0.81) with a DLAD ( < .001). With a DLAD, observers detected more overlooked lung cancers (average sensitivity, 53% [56 of 105 patients] with a DLAD vs 40% [42 of 105 patients] without a DLAD) ( < .001) and recommended chest CT for more patients (62% [66 of 105 patients] with a DLAD vs 47% [49 of 105 patients] without a DLAD) ( < .001). In the healthy control group, no difference existed in the rate of chest CT recommendation (10% [23 of 234 patients] without a DLAD and 8% [20 of 234 patients] with a DLAD) ( = .13). Conclusion Using a deep learning-based automatic detection algorithm may help observers reduce the number of overlooked lung cancers on chest radiographs, without a proportional increase in the number of follow-up chest CT examinations. © RSNA, 2020
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http://dx.doi.org/10.1148/radiol.2020200165DOI Listing
September 2020

Time-Interleaved SAR ADC with Background Timing-Skew Calibration for UWB Wireless Communication in IoT Systems.

Sensors (Basel) 2020 Apr 24;20(8). Epub 2020 Apr 24.

School of Electrical and Electronics Engineering, Chung-Ang University, Seoul 06974, Korea.

Ultra-wideband (UWB) wireless communication is prospering as a powerful partner of the Internet-of-things (IoT). Due to the ongoing development of UWB wireless communications, the demand for high-speed and medium resolution analog-to-digital converters (ADCs) continues to grow. The successive approximation register (SAR) ADCs are the most powerful candidate to meet these demands, attracting both industries and academia. In particular, recent time-interleaved SAR ADCs show that multi-giga sample per second (GS/s) can be achieved by overcoming the challenges of high-speed implementation of existing SAR ADCs. However, there are still critical issues that need to be addressed before the time-interleaved SAR ADCs can be applied in real commercial applications. The most well-known problem is that the time-interleaved SAR ADC architecture requires multiple sub-ADCs, and the mismatches between these sub-ADCs can significantly degrade overall ADC performance. And one of the most difficult mismatches to solve is the sampling timing skew. Recently, research to solve this timing-skew problem has been intensively studied. In this paper, we focus on the cutting-edge timing-skew calibration technique using a window detector. Based on the pros and cons analysis of the existing techniques, we come up with an idea that increases the benefits of the window detector-based timing-skew calibration techniques and minimizes the power and area overheads. Finally, through the continuous development of this idea, we propose a timing-skew calibration technique using a comparator offset-based window detector. To demonstrate the effectiveness of the proposed technique, intensive works were performed, including the design of a 7-bit, 2.5 GS/s 5-channel time-interleaved SAR ADC and various simulations, and the results prove excellent efficacy of signal-to-noise and distortion ratio (SNDR) and spurious-free dynamic range (SFDR) of 40.79 dB and 48.97 dB at Nyquist frequency, respectively, while the proposed window detector occupies only 6.5% of the total active area, and consumes 11% of the total power.
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http://dx.doi.org/10.3390/s20082430DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7219597PMC
April 2020

Sleep deprivation impairs learning and memory by decreasing protein O-GlcNAcylation in the brain of adult zebrafish.

FASEB J 2020 01 27;34(1):853-864. Epub 2019 Nov 27.

Department of Physiology and Biophysics, College of Medicine, Inha University, Incheon, Korea.

Sleep is an evolutionarily conserved physiological process implicated in the consolidation of learning and memory (L/M). Here, we report that sleep deprivation (SD)-induced cognitive deficits in zebrafish are mediated through reduction in O-GlcNAcylation of brain. Microarray-based gene expression profiling of zebrafish brain demonstrated significant changes in genes involved in metabolism by SD or fear conditioning (FC), compared to the control group. In particular, it was observed that a marked decrease in the number of genes involved in carboxylic acid and organic acid metabolic processes in the brains of SD group compared to control group. SD downregulated O-GlcNAc transferase (OGT) and O-GlcNAcylation, while the expression of O-GlcNAcase was upregulated. FC activated protein kinase A (PKA) and phosphorylated cAMP response element binding protein (p-CREB), an effect that was greatly inhibited by SD. Moreover, FC upregulated expressions of OGT and increased O-GlcNAcylation in the brains of normal but not SD zebrafish. Intriguingly, upregulation of O-GlcNAcylation by glucosamine restored defects in L/M functions and PKA/p-CREB activity in SD group. Our findings highlight the O-GlcNAcylation changes in the brain during the L/M process and further provide a foundation for future studies seeking the molecular and biochemical mechanisms by which HBP of glucose metabolism affects cognitive function.
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http://dx.doi.org/10.1096/fj.201901399RRDOI Listing
January 2020

Three-year surveillance of culicine mosquitoes (Diptera: Culicidae) for flavivirus infections in Incheon Metropolitan City and Hwaseong-si of Gyeonggi-do Province, Republic of Korea.

Acta Trop 2020 Feb 13;202:105258. Epub 2019 Nov 13.

Department of Tropical Medicine, Inha University School of Medicine, Incheon 22212, South Korea. Electronic address:

Japanese encephalitis virus (JEV) is a single stranded positive sense RNA virus of the genus Flavivirus that belongs to family Flaviviridae and emerged as one of the most pivotal form of viral encephalitis. The virus is transmitted to humans by mosquito vector and is an etiological agent of acute zoonotic infection. In this study, we investigated distribution and density over 3-year period in central regions of Korean peninsula. We selected two cities as mosquito-collecting locations and subdivided them into five collection sites; downtown Incheon Metropolitan City as a typical urban area, and the Hwaseong-si area as a rural area. A total of 35,445 female culicine mosquitoes were collected using black light traps or BG Sentinel™ traps from March to November 2016-2018. Aedes (Ae.) vexans nipponii was the most frequently collected specimens (48.91%), followed by Culex (Cx.) pipiens (32.05%), Ochlerotatus (Och.) dorsalis (13.58%), Och. koreicus (1.68%), and Cx. tritaeniorhynchus (1.49%). In the urban area, Cx. pipiens was the predominant species (92.21%) and the other species accounted for <5% of the total mosquitoes collected. However, in the rural area, Ae. vexans nipponii had the highest population (61.90%), followed by Och. dorsalis (17.10%), Cx. tritaeniorhynchus (1.84%) and Och, koreicus (1.78%). Culicine mosquitoes were identified at the species level, placed in pools of up to 30 mosquitoes each, and screened for flavivirus RNA using the SYBR Green-based RT-PCR. Three of the assayed 1092 pools were positive for Chaoyang virus from Ae. vexans nipponii and Japanese encephalitis virus from Cx. pipiens. The maximum likelihood estimations (the estimated number of virus-positive mosquitoes/1000 mosquitoes) for Ae. vexans nipponii positive for Chaoyang virus and Cx. pipiens for Japanese encephalitis virus were 3.095 and 0.20, respectively. The results of our study demonstrate that although mosquito-borne diseases were not detected in the potential vectors, enhanced monitoring and long-term surveillance of these vector viruses are of great public health importance.
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http://dx.doi.org/10.1016/j.actatropica.2019.105258DOI Listing
February 2020

Diagnostic accuracy of SOX11 immunohistochemistry in mantle cell lymphoma: A meta-analysis.

PLoS One 2019 12;14(11):e0225096. Epub 2019 Nov 12.

Department of Pathology, Hallym University Dongtan Sacred Heart Hospital, Hwaseong-si, Gyeonggi-do, Republic of Korea.

SOX11 is a transcription factor that is normally expressed in the fetal brain and has also been detected in some malignant tumors, including mantle cell lymphoma (MCL). MCL is a mature B-cell lymphoma that characteristically expresses cyclin D1, which has been used as a diagnostic tumor marker. SOX11 has also recently emerged as a tumor marker for MCL, particularly in cyclin D1-negative MCLs and to distinguish between MCLs and other cyclin D1-positive lymphomas. In this study, we evaluated the diagnostic accuracy of SOX11 immunohistochemistry for the diagnosis of MCL using a meta-analysis. A comprehensive literature search was performed using the PubMED, EMBASE, and Cochrane library through May 9, 2018. In total, 14 studies were included in our meta-analysis. The sensitivity, specificity, and area under the curve calculated from the summary receiver operator characteristic were 0.9, 0.95, and 0.934, respectively. Effect sizes of log positive likelihood ratios, log negative likelihood ratios, and log diagnostic odds ratios were 2.67, -2.12, and 5.27, respectively. Statistically significant substantial heterogeneity was observed for specificity (I2 = 95%), but not for sensitivity. Subgroup analysis and meta-regression were performed to explain the heterogeneity in specificity and showed that the proportions of Burkitt's lymphoma, lymphoblastic lymphoma, and hairy cell leukemia were significant covariates among studies using rabbit polyclonal antibodies. Overall, this meta-analysis showed that SOX11 was a useful diagnostic marker for MCL, with the clone MRQ-58 mouse monoclonal antibody showing particularly robust performance.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0225096PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6850764PMC
March 2020

Blood Pressure Reference Values for Normal Weight Korean Children and Adolescents: Data from The Korea National Health and Nutrition Examination Survey 1998-2016: The Korean Working Group of Pediatric Hypertension.

Korean Circ J 2019 Dec 1;49(12):1167-1180. Epub 2019 Aug 1.

The Korean Working Group of Pediatric Hypertension, Seoul, Korea.

Background And Objectives: Hypertension is becoming one of the most common health conditions in children and adolescents due to increasing childhood obesity. We aimed to provide the auscultatory blood pressure (BP) normative reference values for Korean non-overweight children and adolescents.

Methods: BP measurements in children and adolescents aged 10 to 18 years were performed in the Korean National Health and Nutrition Examination Survey (KNHANES) from 1998 to 2016. BP was measured using a mercury sphygmomanometer. Sex-, age- and height-specific systolic BP (SBP) and diastolic BP (DBP) percentiles were calculated in the non-overweight children (n=10,442). We used the General Additive Model for Location Scale and Shape method to calculate BP percentiles.

Results: The 50th, 90th, 95th, and 99th percentiles of SBP and DBP tables and graphs of non-overweight children and adolescents aged 10 to 18 years were presented by age and height percentiles. We found that the SBP and DBP at the 95th percentile were well correlated with height. The BP tables presented by height contained BP values from 124 cm to 190 cm for boys and from 120 cm to 178 cm for girls. Boys had higher SBP and DBP.

Conclusions: We provided the sex-, age- and height-specific auscultatory BP values using the KNHANES big data. These may be useful in diagnosis and treatment of hypertension in Korean children and adolescents.
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http://dx.doi.org/10.4070/kcj.2019.0075DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6875600PMC
December 2019

Diagnostic Accuracy of Percutaneous Transthoracic Needle Lung Biopsies: A Multicenter Study.

Korean J Radiol 2019 08;20(8):1300-1310

Department of Radiology, Seoul National University College of Medicine, Seoul, Korea.

Objective: To measure the diagnostic accuracy of percutaneous transthoracic needle lung biopsies (PTNBs) on the basis of the intention-to-diagnose principle and identify risk factors for diagnostic failure of PTNBs in a multi-institutional setting.

Materials And Methods: A total of 9384 initial PTNBs performed in 9239 patients (mean patient age, 65 years [range, 20-99 years]) from January 2010 to December 2014 were included. The accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of PTNBs for diagnosis of malignancy were measured. The proportion of diagnostic failures was measured, and their risk factors were identified.

Results: The overall accuracy, sensitivity, specificity, PPV, and NPV were 91.1% (95% confidence interval [CI], 90.6-91.7%), 92.5% (95% CI, 91.9-93.1%), 86.5% (95% CI, 85.0-87.9%), 99.2% (95% CI, 99.0-99.4%), and 84.3% (95% CI, 82.7-85.8%), respectively. The proportion of diagnostic failures was 8.9% (831 of 9384; 95% CI, 8.3-9.4%). The independent risk factors for diagnostic failures were lesions ≤ 1 cm in size (adjusted odds ratio [AOR], 1.86; 95% CI, 1.23-2.81), lesion size 1.1-2 cm (1.75; 1.45-2.11), subsolid lesions (1.81; 1.32-2.49), use of fine needle aspiration only (2.43; 1.80-3.28), final diagnosis of benign lesions (2.18; 1.84-2.58), and final diagnosis of lymphomas (10.66; 6.21-18.30). Use of cone-beam CT (AOR, 0.31; 95% CI, 0.13-0.75) and conventional CT-guidance (0.55; 0.32-0.94) reduced diagnostic failures.

Conclusion: The accuracy of PTNB for diagnosis of malignancy was fairly high in our large-scale multi-institutional cohort. The identified risk factors for diagnostic failure may help reduce diagnostic failure and interpret the biopsy results.
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http://dx.doi.org/10.3348/kjr.2019.0189DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6658880PMC
August 2019

BALLI: Bartlett-adjusted likelihood-based linear model approach for identifying differentially expressed genes with RNA-seq data.

BMC Genomics 2019 Jul 2;20(1):540. Epub 2019 Jul 2.

Interdisciplinary Program of Bioinformatics, Seoul National University, Seoul, 08826, South Korea.

Background: Transcriptomic profiles can improve our understanding of the phenotypic molecular basis of biological research, and many statistical methods have been proposed to identify differentially expressed genes (DEGs) under two or more conditions with RNA-seq data. However, statistical analyses with RNA-seq data are often limited by small sample sizes, and global variance estimates of RNA expression levels have been utilized as prior distributions for gene-specific variance estimates, making it difficult to generalize the methods to more complicated settings. We herein proposed a Bartlett-Adjusted Likelihood-based LInear mixed model approach (BALLI) to analyze more complicated RNA-seq data. The proposed method estimates the technical and biological variances with a linear mixed-effects model, with and without adjusting small sample bias using Bartlkett's corrections.

Results: We conducted extensive simulations to compare the performance of BALLI with those of existing approaches (edgeR, DESeq2, and voom). Results from the simulation studies showed that BALLI correctly controlled the type-1 error rates at various nominal significance levels and produced better statistical power and precision estimates than those of other competing methods in various scenarios. Furthermore, BALLI was robust to variation of library size. It was also successfully applied to Holstein milk yield data, illustrating its practical value. CONCLUSIONS;: BALLI is statistically more efficient and valid than existing methods, and we conclude that it is useful for identifying DEGs in RNA-seq analysis.
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http://dx.doi.org/10.1186/s12864-019-5851-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6604381PMC
July 2019

Nondiagnostic Percutaneous Transthoracic Needle Biopsy of Lung Lesions: A Multicenter Study of Malignancy Risk.

Radiology 2019 03 18;290(3):814-823. Epub 2018 Dec 18.

From the Department of Radiology, Seoul National University Bundang Hospital, Gyeonggi-do, South Korea (K.H.L.); Department of Radiology, National Cancer Center, Gyeonggi-do, South Korea (K.Y.L.); Department of Radiology, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea (Y.J.S., J.H.); Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea (J.H.); Department of Radiology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, South Korea (D.H.H.); Department of Radiology, Inje University Sanggyepaik Hospital, Seoul, South Korea (M.J.K.); Department of Radiology, Korea University Ansan Hospital, Korea University College of Medicine, Gyeonggi-do, South Korea (J.Y.C., C.K.); Department of Radiology, Kyung Hee University Hospital at Gangdong, College of Medicine, Kyung Hee University, Seoul, South Korea (J.I.K.); Department of Radiology, Seoul National University College of Medicine, Seoul, South Korea (S.H.Y., C.M.P.); Department of Statistics, Inha University, Incheon, South Korea (W.L.); and Institute of Radiation Medicine, Seoul National University Medical Research Center, 101 Daehak-ro, Jongno-gu, Seoul 03080, South Korea (C.M.P.).

Purpose To evaluate the malignancy risk of lung lesions that show nondiagnostic results at transthoracic needle biopsy (PTNB) of the lung and to identify any malignancy-associated risk factors in each nondiagnostic category. Materials and Methods In this retrospective study, 9384 initial PTNBs (9239 patients [mean age, 65 years; age range, 20-99 years] consisting of 5729 men [mean age, 66 years; age range, 20-99 years] and 3510 women [mean age, 63 years; age range, 20-94 years]) were performed in eight institutions between January 2010 and December 2014. PTNB results were categorized as diagnostic (malignant or specifically benign) or nondiagnostic (nonspecific benign pathologic findings, atypical cells, or insufficient specimen), and the proportion of final malignant diagnoses per nondiagnostic category was obtained. Malignancy-associated factors were determined by using multivariable analyses. Results Nondiagnostic results were present in 27.6% (2590 of 9384) of PTNBs. Proportions of final malignant diagnoses were 21.3% (339 of 1592) for nonspecific benignities, 90.1% (503 of 558) for atypical cells, and 46.6% (205 of 440) for insufficient specimens. In the nonspecific benign category, granulomatous inflammation (odds ratio [OR], 0.04; 95% confidence interval [CI]: 0.02, 0.12; P < .001), abscess (OR, 0.04; 95% CI: 0.01, 0.28; P = .001), and organizing pneumonia (OR, 0.05; 95% CI: 0.01, 0.23; P < .001) were demonstrated to be important factors negating malignancy. Atypical cells suspicious for malignancy were more associated with malignancy (OR, 6.3; 95% CI: 1.9, 21.0; P = .003) than were atypical cells of indeterminate malignancy. All 130 lesions with atypical cells suggestive of malignancy were finally malignant. Conclusion After nondiagnostic lung biopsies, lesions categorized as atypical cell lesions have a high likelihood of malignancy, with somewhat lower likelihood for lesions with insufficient specimens and nonspecific benign categories. © RSNA, 2018 Online supplemental material is available for this article. See also the editorial by Elicker in this issue.
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http://dx.doi.org/10.1148/radiol.2018181482DOI Listing
March 2019

Comparative Assessment of Diagnostic Performances of Two Commercial Rapid Diagnostic Test Kits for Detection of Plasmodium spp. in Ugandan Patients with Malaria.

Korean J Parasitol 2018 Oct 31;56(5):447-452. Epub 2018 Oct 31.

Department of Statistics, Inha University College of Natural Sciences, Incheon 22212, Korea.

Prompt diagnosis of malaria cases with rapid diagnostic tests (RDTs) has been widely adopted as an effective malaria diagnostic tool in many malaria endemic countries, primarily due to their easy operation, fast result output, and straightforward interpretation. However, there has been controversy about the diagnostic accuracy of RDTs. This study was conducted to evaluate the diagnostic performances of the 2 commercially available malaria RDT kits, RapiGEN Malaria Ag Pf/Pv (pLDH/pLDH) and Asan EasyTestTM Malaria Ag Pf/Pv (HRP-2/pLDH) for their abilities to detect Plasmodium species in blood samples collected from Ugandan patients with malaria. To evaluate the diagnostic performances of these 2 RDT kits, 229 blood samples were tested for malaria infection by microscopic examination and a species-specific nested polymerase chain reaction. The detection sensitivities for P. falciparum of Malaria Ag Pf/Pv (pLDH/pLDH) and Asan EasyTestTM Malaria Ag Pf/Pv (HRP-2/pLDH) were 87.83% and 89.57%, respectively. The specificities of the 2 RDTs were 100% for P. falciparum and mixed P. falciparum/P. vivax infections. These results suggest that the 2 RDT kits showed reasonable levels of diagnostic performances for detection of the malaria parasites from Ugandan patients. However, neither kit could effectively detect P. falciparum infections with low parasitaemia (<500 parasites/μl).
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http://dx.doi.org/10.3347/kjp.2018.56.5.447DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6243188PMC
October 2018

Likelihood-based inference for bounds of causal parameters.

Stat Med 2018 12 28;37(30):4695-4706. Epub 2018 Aug 28.

Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.

It is a common causal inference problem that, even with theoretically infinite samples, we might be able to only provide bounds for the parameters of interest. This problem occurs naturally, for example, in estimating causal interaction between two risk factors and in estimating the average causal effect using the instrumental variable or Mendelian randomization method. Current procedures include linear programming to get the estimated bounds, plus bootstrapping to get confidence intervals. We describe a likelihood-based procedure that automatically yields the interval estimate from the flat likelihood region and show some theory that allows us to construct confidence intervals from this non-regular likelihood. Finally, we illustrate the procedure with examples from the estimation of causal interaction between two risk factors and the treatment effect under partial compliance.
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http://dx.doi.org/10.1002/sim.7949DOI Listing
December 2018

Retraction to: Memory-Enhancing Effects of Silk Fibroin-Derived Peptides in Scopolamine-Treated Mice.

J Microbiol Biotechnol 2016 12;26(12):2228

BrainOn Inc., Seoul 150-037, Republic of Korea.

This article has been retracted from JMB for misconduct of the authors (data fabrication and falsification). JMB as the publisher regrets for any inconvenience caused by the retraction.
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http://dx.doi.org/10.4014/jmb.2016.26.12.2228DOI Listing
December 2016
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