Publications by authors named "Seung-Yeon Kim"

61 Publications

Assessment of optimal chest compression depth during neonatal cardiopulmonary resuscitation: a randomised controlled animal trial.

Arch Dis Child Fetal Neonatal Ed 2021 Jul 30. Epub 2021 Jul 30.

Centre for the Studies of Asphyxia and Resuscitation, Neonatal Research Unit, University of Alberta, Edmonton, Alberta, Canada

Aim: The study aimed to examine the optimal anterior-posterior depth which will reduce the time to return of spontaneous circulation and improve survival during chest compressions. Asphyxiated neonatal piglets receiving chest compression resuscitated with a 40% anterior-posterior chest depth compared with 33%, 25% or 12.5% will have reduced time to return of spontaneous circulation and improved survival.

Methods: Newborn piglets (n=8 per group) were anaesthetised, intubated, instrumented and exposed to 45 min normocapnic hypoxia followed by asphyxia and cardiac arrest. Piglets were randomly allocated to four intervention groups ('anterior-posterior 12.5% depth', 'anterior-posterior 25% depth', 'anterior-posterior 33% depth' or 'anterior-posterior 40% depth'). Chest compressions were performed using an automated chest compression machine with a rate of 90 per minute. Haemodynamic and respiratory parameters, applied compression force, and chest compression depth were continuously measured.

Results: The median (IQR) time to return of spontaneous circulation was 600 (600-600) s, 135 (90-589) s, 85 (71-158)* s and 116 (63-173)* s for the 12.5%, 25%, 33% and 40% depth groups, respectively (*p<0.001 vs 12.5%). The number of piglets that achieved return of spontaneous circulation was 0 (0%), 6 (75%), 7 (88%) and 7 (88%) in the 12.5%, 25%, 33% and 40% anterior-posterior depth groups, respectively. Arterial blood pressure, central venous pressure, carotid blood flow, applied compression force, tidal volume and minute ventilation increased with greater anterior-posterior chest depth during chest compression.

Conclusions: Time to return of spontaneous circulation and survival were similar between 25%, 33% and 40% anterior-posterior depths, while 12.5% anterior-posterior depth did not result in return of spontaneous circulation or survival. Haemodynamic and respiratory parameters improved with increasing anterior-posterior depth, suggesting improved organ perfusion and oxygen delivery with 33%-40% anterior-posterior depth.

Trial Registration Number: PTCE0000193.
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http://dx.doi.org/10.1136/archdischild-2021-321860DOI Listing
July 2021

Relationship between DNA mismatch repair and CRISPR/Cas9-mediated knock-in in the bovine β-casein gene locus.

Anim Biosci 2021 Jun 24. Epub 2021 Jun 24.

Department of Animal Science, Chonnam National University, Gwangju 61186, Korea.

Objective: Efficient gene editing technology is critical for successful knock-in in domestic animals. RAD51 gene plays an important role in strand invasion during homologous recombination (HR) in mammals, and is regulated by CHK1 and CHK2 genes, which are upstream elements of RAD51. In addition, mismatch repair (MMR) system is inextricably linked to HR-related pathways and regulates HR via heteroduplex rejection. Thus, the aim of this study was to investigate whether CRISPR/Cas9-mediated knock-in efficiency of human lactoferrin (hLF) knock-in vector in the bovine β-casein gene locus can be increased by suppressing DNA mismatch repair (MMR)-related genes (MSH2, MSH3, MSH6, MLH1 and PMS2) and overexpressing DNA double-strand break (DSB) repair-related genes (RAD51, CHK1, CHK2).

Methods: MAC-T cells were transfected with a knock-in vector, RAD51, CHK1 or CHK2 overexpression vector and CRISPR/sgRNA expression vector to target the bovine β-casein gene locus, followed by treatment of the cells with CdCl2 for 24 hours. After 3 days of CdCl2 treatment, the knock-in efficiency was confirmed by polymerase chain reaction (PCR). The mRNA expression levels of DNA MMR-related and DNA DSB repair-related genes were assessed by quantitative real-time PCR (RT-qPCR).

Results: Treatment with CdCl2 decreased the mRNA expression of RAD51 and MMR-related genes but did not increase the knock-in efficiency in MAC-T cells. Also, the overexpression of DNA DSB repair-related genes in MAC-T cells did not significantly affect the mRNA expression of MMR-related genes and failed to increase the knock-in efficiency.

Conclusion: Treatment with CdCl2 inhibited the mRNA levels of RAD51 and DNA MMR-related genes in MAC-T cells. However, the function of MMR pathway in relation to HR may differ in various cell types or species.
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http://dx.doi.org/10.5713/ab.21.0117DOI Listing
June 2021

Sustained Inflation During Chest Compression: A New Technique of Pediatric Cardiopulmonary Resuscitation That Improves Recovery and Survival in a Pediatric Porcine Model.

J Am Heart Assoc 2021 Aug 21;10(15):e019136. Epub 2021 Jul 21.

Neonatal Research Unit, Centre for the Studies of Asphyxia and Resuscitation Royal Alexandra Hospital Edmonton Alberta Canada.

Background Chest compression (CC) during sustained inflations (CC+SI) compared with CC with asynchronized ventilation (CCaV) during cardiopulmonary resuscitation in asphyxiated pediatric piglets will reduce time to return of spontaneous circulation (ROSC). Methods and Results Piglets (20-23 days of age, weighing 6.2-10.2 kg) were anesthetized, intubated, instrumented, and exposed to asphyxia. Cardiac arrest was defined as mean arterial blood pressure <25 mm Hg with bradycardia. After cardiac arrest, piglets were randomized to CC+SI (n=12) or CCaV (n=12) or sham (n=8). Sham-operated animals had no asphyxia. Heart rate, arterial blood pressure, carotid blood flow, cerebral oxygenation, and respiratory parameters were continuously recorded. There were no differences in baseline parameters or the duration and degree of asphyxiation. Median (interquartile range) Time to ROSC was 248 (41-346) seconds compared with 720 (167-720) seconds in the CC+SI group and CCaV group, respectively (=0.0292). There was a 100% higher rate of ROSC in the CC+SI group versus CCaV group, with 10 (83%) versus 5 (42%) achieving ROSC (=0.089), respectively. Piglets in the CC+SI and CCaV groups received intravenous epinephrine boluses to achieve ROSC (8/12 versus 10/12 =0.639). There was a significantly higher minute ventilation in the CC+SI group, which was secondary to a 5-fold increase in the number of inflations per minute and a 1.5-fold increase in tidal volume. Conclusions CC+SI reduced time to ROSC and improved survival compared with using CCaV. CC+SI allowed passive ventilation of the lung while providing chest compressions. This technique warrants further studies to examine the potential to improve outcomes in pediatric patients with cardiac arrest. Registration URL: https://www.preclinicaltrials.eu; Unique identifier: PCTE0000152.
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http://dx.doi.org/10.1161/JAHA.120.019136DOI Listing
August 2021

Squaramide-Catalyzed Asymmetric Intramolecular Oxa-Michael Reaction of α,β-Unsaturated Carbonyls Containing Benzyl Alcohol: Construction of Chiral 1-Substituted Phthalans.

J Org Chem 2021 May 27;86(9):6826-6839. Epub 2021 Apr 27.

Department of Chemistry, College of Natural Science, Kyonggi University, 154-42 Gwanggyosan-ro, Yeongtong-gu, Suwon 16227, Republic of Korea.

Organocatalytic enantioselective intramolecular oxa-Michael reactions of benzyl alcohol bearing α,β-unsaturated carbonyls as Michael acceptors are presented herein. Using cinchona squaramide-based organocatalyst, enones as well as α,β-unsaturated esters containing benzyl alcohol provided their corresponding 1,3-dihydroisobenzofuranyl-1-methylene ketones and 1,3-dihydroisobenzofuranyl-1-methylene esters in excellent yields with high enantioselectivities. In addition, enantioenriched 1,3-dihydroisobenzofuranyl-1-methylene ketone could be obtained from the Wittig/oxa-Michael reaction cascade of 1,3-dihydro-2-benzofuran-1-ol.
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http://dx.doi.org/10.1021/acs.joc.1c00715DOI Listing
May 2021

Is Chest Compression Superimposed with Sustained Inflation during Cardiopulmonary Resuscitation an Alternative to 3:1 Compression to Ventilation Ratio in Newborn Infants?

Children (Basel) 2021 Feb 2;8(2). Epub 2021 Feb 2.

Centre for the Studies of Asphyxia and Resuscitation, Neonatal Research Unit, Royal Alexandra Hospital, Edmonton, AB T5H 3V9, Canada.

Approximately 0.1% for term and 10-15% of preterm infants receive chest compression (CC) in the delivery room, with high incidence of mortality and neurologic impairment. The poor prognosis associated with receiving CC in the delivery room has raised concerns as to whether specifically-tailored cardiopulmonary resuscitation methods are needed. The current neonatal resuscitation guidelines recommend a 3:1 compression:ventilation ratio; however, the most effective approach to deliver chest compression is unknown. We recently demonstrated that providing continuous chest compression superimposed with a high distending pressure or sustained inflation significantly reduced time to return of spontaneous circulation and mortality while improving respiratory and cardiovascular parameters in asphyxiated piglet and newborn infants. This review summarizes the current available evidence of continuous chest compression superimposed with a sustained inflation.
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http://dx.doi.org/10.3390/children8020097DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7913022PMC
February 2021

Asphyxiated Female and Male Newborn Piglets Have Similar Outcomes With Different Cardiopulmonary Resuscitation Interventions.

Front Pediatr 2020 3;8:602228. Epub 2020 Dec 3.

Neonatal Research Unit, Centre for the Studies of Asphyxia and Resuscitation, Royal Alexandra Hospital, Edmonton, AB, Canada.

Male newborns have a greater risk of poor cardiovascular and respiratory outcomes compared to females. The mechanisms associated with the "male disadvantage" remains unclear. We have previously shown no difference between male and female newborn piglets during hypoxia, asphyxia, resuscitation, and post-resuscitation recovery. However, it is unknown if there are differences in resuscitation outcomes between males and females during different cardiopulmonary resuscitation techniques. Secondary analysis of 184 term newborn mixed breed duroc piglets (1-3 days of age, weighing 2.0 (0.2) kg) from seven different studies, which were exposed to 30-50 min of normocapnic hypoxia followed by asphyxia until asystole. This was followed by cardiopulmonary resuscitation. For the analysis, piglets were divided into male and female groups, as well as resuscitation technique groups (sustained inflation, 3:1 compression-to-ventilation ratio, or asynchronous ventilations during chest compressions). Cardiac function, carotid blood flow, and cerebral oxygenation were continuously recorded throughout the experiment. Regardless of resuscitation technique, there was no significant difference between males and females in the number achieving return of spontaneous circulation (ROSC) [95/123 (77%) vs. 48/61 (79%)], the time to achieve ROSC [112 (80-185) s vs. 110 (77-186) s], and the 4-h survival rate [81/95 (85%) vs. 40/48 (83%)]. Levels of the injury markers interleukin (IL)-1ß, IL-6, IL-8, and tumor necrosis factor-α in frontoparietal cortex tissue homogenates were similar between males and females. Regardless of resuscitation technique, there was no significant effect of sex on resuscitation outcome, survival, and hemodynamic recovery in asphyxiated newborn piglets.
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http://dx.doi.org/10.3389/fped.2020.602228DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7793777PMC
December 2020

Success Probability Characterization of Long-Range in Low-Power Wide Area Networks.

Sensors (Basel) 2020 Nov 30;20(23). Epub 2020 Nov 30.

Department of Computer Convergence Software, Korea University, Sejong 30019, Korea.

In low-power wide area networks (LPWAN), a considerable number of end devices (EDs) communicate with the gateway in a certain area, whereas for transmitted data, a low data rate and high latency are allowed. Long-range (LoRa), as one of the LPWAN technologies, considers pure ALOHA and chirp spread spectrum (CSS) in the media access control (MAC) and physical (PHY) layers such that it can improve the energy efficiency while mitigating inter-cell interference (ICI). This paper investigates the system throughput of LoRa networks under the assumption that the interferences between EDs for exclusive regions are ignored using CSS. In order to establish an analytical model for the performance of LoRa, we introduce the pure ALOHA capture model, which is the power threshold model. For this model, we assume that the interfering power is proportional to the length of the time overlapped. In addition, we discuss LoRa gain by comparing the total throughput of LoRa with that of non-CSS.
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http://dx.doi.org/10.3390/s20236861DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7730519PMC
November 2020

Highly efficient double plasma mirror producing ultrahigh-contrast multi-petawatt laser pulses.

Opt Lett 2020 Dec;45(23):6342-6345

We present a highly efficient double plasma mirror (DPM) that provides ultrahigh-contrast multi-petawatt (PW) laser pulses with a temporal contrast ratio reaching 10 up to 160 ps and 10 up to 2 ps before the main pulse. The high reflectivity of 70%, along with the high-contrast enhancement factor of 700,000, was achieved from the DPM installed after the final stage of a 4 PW Ti:sapphire laser. The 4 PW laser was equipped with cross-polarized wave generation and optical parametric chirped-pulse amplification stages for initial high-contrast operation. The DPM operation was undertaken with conditions that did not modify the spatiotemporal profiles of incident multi-PW laser pulses. This highly efficient DPM with the high-contrast enhancement promises the utilization of multiple PMs as a practical rear end for upcoming tens of petawatt lasers to achieve ultrahigh temporal contrast.
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http://dx.doi.org/10.1364/OL.409749DOI Listing
December 2020

Assessment of long-range transboundary aerosols in Seoul, South Korea from Geostationary Ocean Color Imager (GOCI) and ground-based observations.

Environ Pollut 2021 Jan 6;269:115924. Epub 2020 Nov 6.

Emory University, Rollins School of Public Health, Atlanta, GA, 30322, USA.

To better understand air quality issues in South Korea, it is essential to identify the main contributors of air pollution and to quantify the effects of transboundary transport. In this study, geostationary satellite measurements were used to assess the effects of aerosol transport on air quality in South Korea. This study proposes a method to define the long-range transport (LRT) of aerosols into the Korean Peninsula using remote sensing obervations and back-trajectories and estimates the LRT effects on air quality in Seoul using in-situ particulate matter (PM) measurements. Aerosol optical depths (AODs) are obtained from the Geostationary Ocean Color Imager (GOCI), and the back-trajectories are from the National Ocean and Atmospheric Administration (NOAA) HYbrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model. For LRT events, satellite observations showed high AOD plumes over the Yellow Sea, a pathway between Eastern China and South Korea, and the movements of aerosol plumes transported to South Korea were also detected. PM concentrations, PM concentrations, and AOD during LRT increased by 52%, 49%, and 81%, respectively, relative to their average values for 2015-2018. To quantitatively characterize the LRT of aerosols, the effects of LRT on PM concentrations were estimated for each PM concentration category. The contribution of LRT to PM concentrations was estimated to be 33% during 2015-2018. When high concentrations of PM were observed in Seoul, they were likely to be associated with LRT events.
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http://dx.doi.org/10.1016/j.envpol.2020.115924DOI Listing
January 2021

Dietary Antioxidants and the Mitochondrial Quality Control: Their Potential Roles in Parkinson's Disease Treatment.

Antioxidants (Basel) 2020 Oct 28;9(11). Epub 2020 Oct 28.

Department of Brain & Cognitive Sciences, DGIST, Daegu 42988, Korea.

Advances in medicine and dietary standards over recent decades have remarkably increased human life expectancy. Unfortunately, the chance of developing age-related diseases, including neurodegenerative diseases (NDDs), increases with increased life expectancy. High metabolic demands of neurons are met by mitochondria, damage of which is thought to contribute to the development of many NDDs including Parkinson's disease (PD). Mitochondrial damage is closely associated with the abnormal production of reactive oxygen species (ROS), which are widely known to be toxic in various cellular environments, including NDD contexts. Thus, ways to prevent or slow mitochondrial dysfunction are needed for the treatment of these NDDs. In this review, we first detail how ROS are associated with mitochondrial dysfunction and review the cellular mechanisms, such as the mitochondrial quality control (MQC) system, by which neurons defend against both abnormal production of ROS and the subsequent accumulation of damaged mitochondria. We next highlight previous studies that link mitochondrial dysfunction with PD and how dietary antioxidants might provide reinforcement of the MQC system. Finally, we discuss how aging plays a role in mitochondrial dysfunction and PD before considering how healthy aging through proper diet and exercise may be salutary.
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http://dx.doi.org/10.3390/antiox9111056DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7692176PMC
October 2020

Ataxin-2 Dysregulation Triggers a Compensatory Fragile X Mental Retardation Protein Decrease in C4da Neurons.

Mol Cells 2020 Oct;43(10):870-879

Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 42988, Korea.

Dendrites require precise and timely delivery of protein substrates to distal areas to ensure the correct morphology and function of neurons. Many of these protein substrates are supplied in the form of ribonucleoprotein (RNP) complex consisting of RNA-binding proteins (RBPs) and mRNAs, which are subsequently translated in distal dendritic areas. It remains elusive, however, whether key RBPs supply mRNA according to local demands individually or in a coordinated manner. In this study, we investigated how sensory neurons respond to the dysregulation of a disease-associated RBP, Ataxin-2 (ATX2), which leads to dendritic defects. We found that ATX2 plays a crucial role in spacing dendritic branches for the optimal dendritic receptive fields in class IV dendritic arborization (C4da) neurons, where both expression level and subcellular location of ATX2 contribute significantly to this effect. We showed that translational upregulation through the expression of eukaryotic translation initiation factor 4E (eIF4E) further enhanced the ATX2-induced dendritic phenotypes. Additionally, we found that the expression level of another disease-associated RBP, fragile X mental retardation protein (FMRP), decreased in both cell bodies and dendrites when neurons were faced with aberrant upregulation of ATX2. Finally, we revealed that the PAM2 motif of ATX2, which mediates its interaction with poly(A)-binding protein (PABP), is potentially necessary for the decrease of FMRP in certain neuronal stress conditions. Collectively, our data suggest that dysregulation of RBPs triggers a compensatory regulation of other functionally-overlapping RBPs to minimize RBP dysregulation-associated aberrations that hinder neuronal homeostasis in dendrites.
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http://dx.doi.org/10.14348/molcells.2020.0158DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7604024PMC
October 2020

First Case of Peroxisomal D-bifunctional Protein Deficiency with Novel Mutations and Progressive Neuropathy in Korea.

J Korean Med Sci 2020 Oct 12;35(39):e357. Epub 2020 Oct 12.

Department of Pediatrics, Chungnam National University College of Medicine, Chungnam National University Hospital, Daejeon, Korea.

Peroxisomal D-bifunctional protein (DBP), encoded by the gene, catalyzes β-oxidation of very long chain fatty acids (VLCFAs). The deficiency of this peroxisomal enzyme leads to the accumulation of VLCFAs, causing multisystemic manifestations including the brain, retina, adrenal gland, hearing, and skeletal system. Herein, we report the first Korean neonatal case of peroxisomal DBP deficiency and the clinical prognosis over 2 years. This patient showed craniofacial dysmorphism, club foot, and seizures with cyanosis one day after birth. Elevated VLCFAs levels were indicative of a peroxisomal disorder. Targeted exome sequencing was performed and two missense mutations p.Asp117Val and p.Phe279Ser in the gene were identified. The patient had type III DBP deficiency; therefore, docosahexaenoic acid and non-soluble vitamins were administered. However, progressive nystagmus, optic nerve atrophy, and bilateral hearing defects were observed and follow-up brain imaging revealed leukodystrophy and brain atrophy. Multiple anti-epileptic drugs were required to control the seizures. Over two years, the patient achieved normal growth with home ventilation and tube feeding. Hereby, the subject's parents had support during the second pregnancy from the proven molecular information. Moreover, targeted exome sequencing is an effective diagnostic approach, considering genetic heterogeneity of Zellweger spectrum disorders.
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http://dx.doi.org/10.3346/jkms.2020.35.e357DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7550233PMC
October 2020

Gray-brown skin discoloration following phototherapy for hyperbilirubinemia due to anti-E alloimmunization.

Korean J Pediatr 2019 Nov 18;62(11):428-430. Epub 2019 Sep 18.

Department of Pediatrics, Eulji University Hospital, Daejeon, Korea.

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http://dx.doi.org/10.3345/kjp.2019.00528DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6881204PMC
November 2019

Total Biosynthesis for Milligram-Scale Production of Etoposide Intermediates in a Plant Chassis.

J Am Chem Soc 2019 12 27;141(49):19231-19235. Epub 2019 Nov 27.

Etoposide is a plant-derived drug used clinically to treat several forms of cancer. Recent shortages of etoposide demonstrate the need for a more dependable production method to replace the semisynthetic method currently in place, which relies on extraction of a precursor natural product from Himalayan mayapple. Here we report milligram-scale production of (-)-deoxypodophyllotoxin, a late-stage biosynthetic precursor to the etoposide aglycone, using an engineered biosynthetic pathway in tobacco. Our strategy relies on engineering the supply of coniferyl alcohol, an endogenous tobacco metabolite and monolignol precursor to the etoposide aglycone. We show that transient expression of 16 genes, encoding both coniferyl alcohol and main etoposide aglycone pathway enzymes from mayapple, in tobacco leaves results in the accumulation of up to 4.3 mg/g dry plant weight (-)-deoxypodophyllotoxin, and enables isolation of high-purity (-)-deoxypodophyllotoxin after chromatography at levels up to 0.71 mg/g dry plant weight. Our work reveals that long (>10 step) pathways can be efficiently transferred from difficult-to-cultivate medicinal plants to a tobacco plant production chassis, and demonstrates mg-scale total biosynthesis for access to valuable precursors of the chemotherapeutic etoposide.
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http://dx.doi.org/10.1021/jacs.9b10717DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7380830PMC
December 2019

An Investigation of Drug-Drug Interaction Alert Overrides at a Pediatric Hospital.

Hosp Pediatr 2018 05;8(5):293-299

Center for Applied Pediatric Quality Analytics, Boston Children's Hospital, Boston, Massachusetts; and.

Objectives: Drug-drug interactions (DDIs) can result in patient harm. DDI alerts are intended to help prevent harm; when the majority of alerts presented to providers are being overridden, their value is diminished. Our objective was to evaluate the overall rates of DDI alert overrides and how rates varied by specialty, clinician type, and patient complexity.

Methods: A retrospective study of DDI alert overrides that occurred during 2012 and 2013 within the inpatient setting described at the medication-, hospital-, provider-, and patient encounter-specific levels was performed at an urban, quaternary-care, pediatric hospital.

Results: There were >41 000 DDI alerts presented to clinicians; ∼90% were overridden. The 5 DDI pairs that were most frequently presented and overridden included the following: potassium chloride-spironolactone, methadone-ondansetron, ketorolac-ibuprofen, cyclosporine-fluconazole, and potassium chloride-enalapril, each with an alert override rate of ≥0.89. Override rates across provider groups ranged between 0.84 and 0.97. In general, patients with high complexity had a higher frequency of alert overrides, but the rates of alert overrides for each DDI pairing did not differ significantly.

Conclusions: High rates of DDI alert overrides occur across medications, provider groups, and patient encounters. Methods to decrease DDI alerts which are likely to be overridden exist, but it is also clear that more robust and intelligent tools are needed. Characteristics exist at the medication, hospital, provider, and patient levels that can be used to help specialize and enhance information transmission.
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http://dx.doi.org/10.1542/hpeds.2017-0124DOI Listing
May 2018

A pediatric case of idiopathic Harlequin syndrome.

Korean J Pediatr 2016 Nov 30;59(Suppl 1):S125-S128. Epub 2016 Nov 30.

Department of Pediatrics, Eulji University Hospital, Daejeon, Korea.

Harlequin syndrome, which is a rare disorder caused by dysfunction of the autonomic system, manifests as asymmetric facial flushing and sweating in response to heat, exercise, or emotional factors. The syndrome may be primary (idiopathic) with a benign course, or can occur secondary to structural abnormalities or iatrogenic factors. The precise mechanism underlying idiopathic harlequin syndrome remains unclear. Here, we describe a case of a 6-year-old boy who reported left hemifacial flushing and sweating after exercise. He had an unremarkable birth history and no significant medical history. Complete ophthalmological and neurological examinations were performed, and no other abnormalities were identified. Magnetic resonance imaging was performed to exclude lesions of the cerebrum and cervicothoracic spinal cord, and no abnormalities were noted. His final diagnosis was classic idiopathic harlequin syndrome. Herein, we report the first pediatric case of idiopathic harlequin syndrome in Korea.
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http://dx.doi.org/10.3345/kjp.2016.59.11.S125DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5177694PMC
November 2016

Endoscopic Olecranon Bursal Resection for Olecranon Bursitis: A Comparative Study for Septic and Aseptic Olecranon Bursitis.

J Hand Surg Asian Pac Vol 2016 06;21(2):167-72

1 Department of Orthopaedic Surgery, Upper Extremity and Microsurgery Center, Pohang Semyeong Christianity Hospital, Pohang, Korea.

Background: Open excision of the olecranon bursa has been performed traditionally. However, surgical complications such as wound healing problems and recurrence may occur after the surgery. The purpose of this study was to report on the clinical outcomes of endoscopic olecranon bursal resection performed in both septic and aseptic olecranon bursitis.

Methods: We retrospectively reviewed 30 patients who underwent endoscopic olecranon bursal resection from June 2007 to January 2012. There were 20 males and 10 females. The ages ranged from 22 to 80 years, with an average age of 57.4 years and the average follow-up was 21.1 months (6-61.5 months). There were 15 cases in the septic group. The treatment outcome was measured according to the following; the rate of recurrence, range of motion, complications associated with surgery, VAS and QuickDASH.

Results: There were no complications such as postoperative infection or neurovascular injuries. In the septic group, the VAS and QuickDASH scores were significantly improved from 5.6 to 0.1 and from 28 to 1.3, respectively. In the aseptic group, the VAS and QuickDASH scores were improved from 0.6 to 0.1 and from 25.7 to 0.5, respectively. In all cases, there were no recurrences and no limitations of joint motion until the final follow-up.

Conclusions: We were able to obtain excellent outcomes without recurrence by performing endoscopic olecranon bursal resection in both septic and aseptic olecranon bursitis.
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http://dx.doi.org/10.1142/S2424835516500156DOI Listing
June 2016

The Effect and Safety of Steroid Injection in Lumbar Spinal Stenosis: With or Without Local Anesthetics.

Ann Rehabil Med 2016 Feb 26;40(1):14-20. Epub 2016 Feb 26.

Department of Physical Medicine and Rehabilitation, Dongguk University College of Medicine, Goyang, Korea.

Objective: To compare the long-term effect and safety of an epidural steroid injection in spinal stenosis patients, with or without local anesthetics.

Methods: Twenty-nine patients diagnosed with spinal stenosis were included and randomly divided into two groups. Translaminar epidural and selective nerve root spinal injection procedures were performed using steroids mixed with local anesthetics or normal saline. The effects of spinal injection procedures were measured with visual analogue scale (VAS) and functional rate index (FRI). These measurements were performed before injection, at 1 month after injection and at 3 months after injection. The occurrence of side effects was investigated each time.

Results: The VAS and FRI scores were significantly reduced in both the local anesthetics group and normal saline group at 1 and 3 months after the injection. However, there was no significant difference in VAS and FRI score reduction between the two groups each time. Side effects are not noted in both groups.

Conclusion: The spinal injection procedures using steroids mixed either with local anesthetics or normal saline have an effect in reducing pain and improving functional activities. However, there was no significant difference between the two groups in relation to side effects and the long-term effects of pain and function.
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http://dx.doi.org/10.5535/arm.2016.40.1.14DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4775747PMC
February 2016

Production of Metal-Free Composites Composed of Graphite Oxide and Oxidized Carbon Nitride Nanodots and Their Enhanced Photocatalytic Performances.

Chemistry 2016 Apr 25;22(15):5142-5. Epub 2016 Feb 25.

Department of Chemistry and Chemical Engineering, Inha Univeristy, 100 Inha-ro, Nam-gu, Incheon, 402-751, Korea.

A novel metal-free composite (GN) composed of two types of carbon-based nanomaterials, graphite oxide (GO) and 2D oxidized carbon nitride (OCN) nanodots was produced. Chemical and morphological characterizations reveal that GN contains a main component of GO with well-dispersed 2D OCN nanodots. GN shows enhanced photocatalytic performance for degrading an organic pollutant, Rhodamine B, under visible light.
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http://dx.doi.org/10.1002/chem.201505100DOI Listing
April 2016

A Folding Pathway Model of Mini-Protein BBA5.

Biomed Res Int 2015 20;2015:828095. Epub 2015 Sep 20.

Korea Institute for Advanced Study, Seoul 130-722, Republic of Korea.

We present the folding pathway model of mini-protein BBA5, a bundle of secondary structures, α-helix and β-hairpin, by using action-derived molecular dynamics (ADMD) simulations. From ten independent ADMD simulations, we extracted common features of the folding pathway of BBA5, from which we found that the early stage chain compaction was followed by the formation of C-terminal α-helix. The N-terminal β-hairpin was observed to form only after α-helix was stabilized. This result is in good agreement with the experimental observation that BBA5 mutants were moderately cooperative folders, and their C-terminal helical fragments were of higher secondary structure propensity while the N-terminal hairpin fragments were of a random coil spectrum. We found that the most flexible part of BBA5 is the N-terminal four residues. Although both are made of the identical ββα motif, the secondary structure formation sequence of BBA5 is found to be different from that of FSD-1. Finally, a description of the folding pathway in terms of principal component analysis is presented to characterize the folding dynamics in reduced dimensions. With only three principal components, we were able to describe 83.4% of the pathway.
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http://dx.doi.org/10.1155/2015/828095DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4592707PMC
June 2016

Evaluation of three glucometers for whole blood glucose measurements at the point of care in preterm or low-birth-weight infants.

Korean J Pediatr 2015 Aug 21;58(8):301-8. Epub 2015 Aug 21.

Department of Pediatrics, Eulji University School of Medicine, Daejeon, Korea.

Purpose: We evaluated three blood glucose self-monitoring for measuring whole blood glucose levels in preterm and low-birth-weight infants.

Methods: Between December 1, 2012 and March 31, 2013, 230 blood samples were collected from 50 newborns, who weighed, ≤2,300 g or were ≤36 weeks old, in the the neonatal intensive care unit of Eulji University Hospital. Three blood glucose self-monitoring (A: Precision Pcx, Abbott; B: One-Touch Verio, Johnson & Johnson; C: LifeScan SureStep Flexx, Johnson & Johnson) were used for the blood glucose measurements. The results were compared to those obtained using laboratory equipment (D: Advia chemical analyzer, Siemens Healthcare Diagnostics Inc.).

Results: The correlation coefficients between laboratory equipment and the three blood glucose self-monitoring (A, B, and C) were found to be 0.888, 0.884, and 0.900, respectively. For glucose levels≤60 mg/dL, the correlation coefficients were 0.674, 0.687, and 0.679, respectively. For glucose levels>60 mg/dL, the correlation coefficients were 0.822, 0.819, and 0.839, respectively. All correlation coefficients were statistically significant. And the values from the blood glucose self-monitoring were not significantly different from the value of the laboratory equipment , after correcting for each device's average value (P>0.05). When using laboratory equipment (blood glucose ≤60 mg/dL), each device had a sensitivity of 0.458, 0.604, and 0.688 and a specificity of 0.995, 0.989, and 0.989, respectively.

Conclusion: Significant difference is not found between three blood glucose self-monitoring and laboratory equipment. But correlation between the measured values from blood glucose self-monitoring and laboratory equipment is lower in preterm or low-birth-weight infants than adults.
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http://dx.doi.org/10.3345/kjp.2015.58.8.301DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4573444PMC
August 2015

Modular degradable hydrogels based on thiol-reactive oxanorbornadiene linkers.

J Am Chem Soc 2015 Apr 14;137(15):4984-7. Epub 2015 Apr 14.

†Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States.

Oxanorbornadiene dicarboxylate (OND) reagents are potent Michael acceptors, the adducts of which undergo fragmentation by retro-Diels-Alder reaction at rates that vary with the substitution pattern on the OND moiety. Rapid conjugate addition between thiol-terminated tetravalent PEG and multivalent ONDs yielded self-supporting hydrogels within 1 min at physiological temperature and pH. Erosion of representative hydrogel formulations occurred with predictable and pH-independent rates on the order of minutes to weeks. These materials could be made non-degradable by epoxidation of the OND linkers without slowing gelation. Hydrogels prepared with OND linkers of equal valence had comparable physical properties, as determined by equilibrium swelling behavior, indicating similar internal network structure. Diffusion and release of entrained cargo varied with both the rate of degradation of PEG-OND hydrogels and the hydrodynamic radius of the entrained species. These results highlight the utility of OND linkers in the preparation of degradable network materials with potential applications in sustained release.
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http://dx.doi.org/10.1021/jacs.5b02708DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4415036PMC
April 2015

Inducing cells to disperse nickel nanowires via integrin-mediated responses.

Nanotechnology 2015 Mar 12;26(13):135102. Epub 2015 Mar 12.

Electrical and Computer Engineering, University of Minnesota, 4-174 Keller Hall, 200 Union St. SE, Minneapolis, MN-55455, USA.

We present non-cytotoxic, magnetic, Arg-Gly-Asp (RGD)-functionalized nickel nanowires (RGD-nanowires) that trigger specific cellular responses via integrin transmembrane receptors, resulting in dispersal of the nanowires. Time-lapse fluorescence and phase contrast microscopy showed that dispersal of 3 μm long nanowire increased by a factor of 1.54 with functionalization by RGD, compared to polyethylene glycol (PEG), through integrin-specific binding, internalization and proliferation in osteosarcoma cells. Further, a 35.5% increase in cell density was observed in the presence of RGD-nanowires, compared to an increase of only 15.6% with PEG-nanowires. These results promise to advance applications of magnetic nanoparticles in drug delivery, hyperthermia, and cell separation where uniformity and high efficiency in cell targeting is desirable.
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http://dx.doi.org/10.1088/0957-4484/26/13/135102DOI Listing
March 2015

Oxidized carbon nitrides: water-dispersible, atomically thin carbon nitride-based nanodots and their performances as bioimaging probes.

Chemistry 2015 Apr 11;21(16):6241-6. Epub 2015 Mar 11.

Department of Chemistry and Chemical Engineering, Inha University, 100 Inha-ro, Nam-gu, Incheon 402-751 (Korea).

Three-dimensional (3D) carbon nitride (C3 N4 )-based materials show excellent performance in a wide range of applications because of their suitable band structures. To realize the great promise of two-dimensional (2D) allotropes of various 3D materials, it is highly important to develop routes for the production of 2D C3 N4 materials, which are one-atom thick, in order to understand their intrinsic properties and identify their possible applications. In this work, water-dispersible, atomically thin, and small carbon nitride nanodots were produced using the chemical oxidation of graphitic C3 N4 . Various analyses, including X-ray diffraction, X-ray photoelectron, Fourier-transform infrared spectroscopy, and combustion-based elemental analysis, and thermogravimetric analysis, confirmed the production of 3D oxidized C3 N4 materials. The 2D C3 N4 nanodots were successfully exfoliated as individual single layers; their lateral dimension was several tens of nanometers. They showed strong photoluminescence in the visible region as well as excellent performances as cell-imaging probes in an in vitro study using confocal fluorescence microscopy.
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http://dx.doi.org/10.1002/chem.201406151DOI Listing
April 2015

Usefulness of videofluoroscopic swallow study in treacher collins syndrome with cleft palate: a case report.

Ann Rehabil Med 2014 Oct 30;38(5):707-11. Epub 2014 Oct 30.

Department of Physical Medicine & Rehabilitation, Eulji University Hospital, Eulji University School of Medicine, Daejeon, Korea.

A 3-year-old girl had multiple anomalies compatible with Treacher Collins Syndrome (TCS). From the neonatal period, sucking was poor, making tube feeding necessary. Excessive saliva was retained in the oral cavity. Nasal leakage caused by the cleft palate was observed when she spoke. The initial videofluoroscopic swallow study (VFSS) showed a poor posterior bolus transit and nasopharyngeal regurgitation. A delayed swallow reflex and bolus stasis at the vallecular and pyriform sinuses were recognized. Based on the VFSS findings, the patient underwent palatoplasty at 20 months of age. At approximately 23 months of age, a follow-up VFSS was performed; poor posterior bolus transit, nasopharyngeal regurgitation, and delayed swallow reflex were not observed. Finally, the patient was able to eat ground or chopped foods and solid foods orally. We deem VFSS to be helpful in deciding the appropriate management of dysphagia in TCS.
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http://dx.doi.org/10.5535/arm.2014.38.5.707DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4221402PMC
October 2014

The p.R168Q mutation is associated with the Bw phenotype and a predicted decrease in the stability of the resulting ABO glycosyltransferase.

Transfusion 2014 May 28;54(5):1298-304. Epub 2013 Oct 28.

Department of Laboratory Medicine, Chonnam National University Medical School, Gwangju, South Korea.

Background: Mutation of ABO glycosyltransferase (GT) can cause protein stability changes that can result in a weak ABO phenotype. To explain the Bw phenotype of a novel ABO*Bw allele, a protein stability of the mutant GT, which enhances the information of the three-dimensional (3D) structural analysis, was calculated.

Study Design And Methods: ABO serology and genotyping were performed on a neonate and her five family members. A 3D structural analysis of the wild-type GTB and enzymes with a variety of mutations at Residue 168, along with predicted protein stability changes (ΔΔG) and flow cytometric analysis of ABO antigen expression on HeLa cells transfected with plasmids containing R168Q, R168L, and R168P mutants was also performed.

Results: A novel ABO*Bw allele (c.503G>A, p.R168Q) was discovered. The structural analysis of 3D homology modeling predicted reduced protein stability of the mutant GTB, and the ΔΔG values, which inversely correlated with the mean relative fluorescence intensity of ABO antigen expression, quantitatively explained the reduced ABO antigen expression.

Conclusions: The predicted protein stability change of a mutant GT enzyme might be a useful and convenient approach to objectively and quantitatively explain the reduced ABO antigen expression.
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http://dx.doi.org/10.1111/trf.12461DOI Listing
May 2014

Strategic approach to O'Driscoll type 2 anteromedial coronoid facet fracture.

J Shoulder Elbow Surg 2014 Jul 6;23(7):924-32. Epub 2014 May 6.

Department of Orthopaedic Surgery, Upper Extremity and Microsurgery Center, Pohang Semyeng Christianity Hospital, Pohang, Kyeongbuk, South Korea.

Background: The purpose of this study was to suggest a strategic approach to the management of anteromedial coronoid facet (AMCF) fracture that is related to posteromedial rotational instability of the elbow through investigation of the surgical outcome of diverse combinations, including internal fixation of AMCF fractures and repair of collateral ligament injury.

Methods: The study enrolled 18 patients. On the basis of the size of the coronoid fracture and the degree of the soft tissue injuries that were evaluated with computed tomography, magnetic resonance imaging, and varus stress test under anesthesia, these fractures were managed differently. Functional outcomes were evaluated with the visual analog scale score, modified Mayo Elbow Performance Score, and Disabilities of the Arm, Shoulder and Hand score. Plain radiographs were used to evaluate the degree of arthrosis.

Results: There were 2 cases of O'Driscoll type 2, subtype 1 fractures; 14 cases of type 2, subtype 2 fractures; and 2 cases of type 2, subtype 3 fractures. Seven cases were managed with only AMCF fracture fixation, 4 cases with only lateral ulnar collateral ligament (LUCL) repair, 6 cases with concomitant repair of the LUCL and AMCF fracture, and 1 case with a conservative method. There were no significant differences among O'Driscoll types and among the subgroups of type 2-2 (P > .05). When the elbow showed instability on the varus stress test after AMCF fracture fixation, the soft tissue injuries of the lateral elbow were more severe (P =. 015). Arthrosis was not correlated with the patient's symptoms (P > .05).

Conclusion: AMCF fracture can be treated by only AMCF fracture fixation, only LUCL repair, or a combination of these techniques, depending on the size of the AMCF fracture fragment and the degree of the lateral soft tissue injuries.
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http://dx.doi.org/10.1016/j.jse.2014.02.016DOI Listing
July 2014

Pneumonectomy case in a newborn with congenital pulmonary lymphangiectasia.

J Korean Med Sci 2014 Apr 1;29(4):609-13. Epub 2014 Apr 1.

Department of Pediatrics, Eulji University College of Medicine, Daejeon, Korea.

Congenital pulmonary lymphangiectasia (CPL) is a rare lymphatic pulmonary abnormality. CPL with respiratory distress has a poor prognosis, and is frequently fatal in neonates. We report a case of pneumonectomy for CPL in a newborn. An infant girl, born at 39 weeks' after an uncomplicated pregnancy, exhibited respiratory distress 1 hr after birth, which necessitated intubation and aggressive ventilator care. Right pneumonectomy was performed after her symptoms worsened. Histologic examination indicated CPL. She is currently 12 months old and developing normally. Pneumonectomy can be considered for treating respiratory symptoms for improving chances of survival in cases with unilateral CPL.
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http://dx.doi.org/10.3346/jkms.2014.29.4.609DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3991809PMC
April 2014

Transition pathway and its free-energy profile: a protocol for protein folding simulations.

Int J Mol Sci 2013 Aug 2;14(8):16058-75. Epub 2013 Aug 2.

Korea Research Institute of Standards and Science, Daejon 305-340, Korea.

We propose a protocol that provides a systematic definition of reaction coordinate and related free-energy profile as the function of temperature for the protein-folding simulation. First, using action-derived molecular dynamics (ADMD), we investigate the dynamic folding pathway model of a protein between a fixed extended conformation and a compact conformation. We choose the pathway model to be the reaction coordinate, and the folding and unfolding processes are characterized by the ADMD step index, in contrast to the common a priori reaction coordinate as used in conventional studies. Second, we calculate free-energy profile as the function of temperature, by employing the replica-exchange molecular dynamics (REMD) method. The current method provides efficient exploration of conformational space and proper characterization of protein folding/unfolding dynamics from/to an arbitrary extended conformation. We demonstrate that combination of the two simulation methods, ADMD and REMD, provides understanding on molecular conformational changes in proteins. The protocol is tested on a small protein, penta-peptide of met-enkephalin. For the neuropeptide met-enkephalin system, folded, extended, and intermediate sates are well-defined through the free-energy profile over the reaction coordinate. Results are consistent with those in the literature.
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http://dx.doi.org/10.3390/ijms140816058DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3759899PMC
August 2013

Dynamic folding pathway models of the Trp-cage protein.

Biomed Res Int 2013 24;2013:973867. Epub 2013 Jun 24.

Korea Research Institute of Standards and Science, Daejon 305-600, Republic of Korea.

Using action-derived molecular dynamics (ADMD), we study the dynamic folding pathway models of the Trp-cage protein by providing its sequential conformational changes from its initial disordered structure to the final native structure at atomic details. We find that the numbers of native contacts and native hydrogen bonds are highly correlated, implying that the native structure of Trp-cage is achieved through the concurrent formations of native contacts and native hydrogen bonds. In early stage, an unfolded state appears with partially formed native contacts (~40%) and native hydrogen bonds (~30%). Afterward, the folding is initiated by the contact of the side chain of Tyr3 with that of Trp6, together with the formation of the N-terminal α -helix. Then, the C-terminal polyproline structure docks onto the Trp6 and Tyr3 rings, resulting in the formations of the hydrophobic core of Trp-cage and its near-native state. Finally, the slow adjustment processes of the near-native states into the native structure are dominant in later stage. The ADMD results are in agreement with those of the experimental folding studies on Trp-cage and consistent with most of other computational studies.
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http://dx.doi.org/10.1155/2013/973867DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3707288PMC
February 2014
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