Publications by authors named "Chang-kyu Lee"

The bioactive glass-ceramic spacer (BGS)-7, a biosynthetic intervertebral fusion material introduced in 2014, has not been the subject of comparative clinical studies on anterior cervical discectomy and fusion (ACDF) surgery. This study, for the first time, aims to compare the radiological and clinical outcomes of the renewed BGS-7, released in 2019, with those of an allograft spacer. The comparison includes a finite element analysis of the biomechanical properties of each implant, adding a novel dimension to the research.

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Background: The goal of this study was to develop and validate a UPLC-MS/MS method for simultaneous mea-surement of 13 AEDs, including carbamazepine, oxcarbazepine, lamotrigine, levetiracetam, topiramate, primidone, zonisamide, gabapentin, lacosamide, perampanel, pregabalin, rufinamide, and vigabatrin, in whole blood samples.

Methods: A UPLC-MS/MS method for simultaneous determination of 13 AEDs in whole blood was developed, and validation was conducted for accuracy, precision, limit of quantification (LOQ), matrix effect, and stability. Our method was compared to two different hospitals using UPLC-MS/MS.

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The invention of Light Emitting Diode (LED) revolutionized energy-efficient illumination, but concerns persist regarding the potential harm of blue light to our eyes. In this study, we scrutinized the impact of LED light characteristics on eyes using two cell types: M-1 (rich in mitochondria) and CD-1 (neuronal). Variations in color rendering index (CRI) and correlated color temperature (CCT) were investigated, alongside exposure durations ranging from 0 to 24 hours.

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Article Synopsis
  • Dysregulated immune responses during infections can cause sepsis, leading to multiple organ dysfunction and highlighting the need for new treatment approaches.
  • CE9A215 (inotodiol), a compound derived from fungi, has shown potential anti-inflammatory effects by reducing pro-inflammatory cytokines in both cell cultures and animal models.
  • The study found that CE9A215 improved survival in mice with sepsis while promoting the clearance of harmful lipopolysaccharides by enhancing specific proteins associated with lipid transport, suggesting its potential as a new therapy for sepsis.
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Here, we examined the effects of the BMP signaling pathway inhibitor LDN-193189 on the pluripotency of porcine embryonic stem cells (ESCs) in the absence of feeder cells using molecular and transcriptomic techniques. Additionally, the effects of some extracellular matrix components on porcine ESC pluripotency were evaluated to develop an optimized and sustainable feeder-free culture system for porcine ESCs. Feeder cells were found to play an important role in supporting the pluripotency of porcine ESCs by blocking trophoblast and mesodermal differentiation through the inhibition of the BMP pathway.

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This cadaveric study aimed to evaluate the safety and usability of a novel robotic system for posterior cervical pedicle screw fixation. Three human cadaveric specimens and C2-T3 were included. Freshly frozen human cadaver specimens were prepared and subjected to robot-assisted posterior cervical pedicle screw fixation using the robotic system.

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This study assessed the performance of the BioFire Blood Culture Identification 2 (BCID2) panel in identifying microorganisms and antimicrobial resistance (AMR) profiles in positive blood cultures (BCs) and its influence on turnaround time (TAT) compared with conventional culture methods. We obtained 117 positive BCs, of these, 102 (87.2%) were correctly identified using BCID2.

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Purpose: This study aimed to evaluate the prognostic factors affecting surgical outcomes, including visual acuity (VA) improvement, after glaucoma surgery in patients with neovascular glaucoma (NVG).

Methods: The medical records of 116 patients (116 eyes) with NVG who had undergone trabeculectomy or Ahmed glaucoma valve implantation were reviewed retrospectively. The primary outcome measure was surgical success at 6 postoperative months, defined as sufficient intraocular pressure (IOP) reduction (IOP ≤21 mmHg, ≥20% reduction, regardless of topical medication use) without additional glaucoma surgery, hypotony, or progression to no light perception.

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Article Synopsis
  • This study investigates how vaccination affects the ability to neutralize different variants of SARS-CoV-2, particularly delta and omicron, in COVID-19 infected individuals.
  • Data from 97 confirmed COVID-19 cases revealed that vaccinated individuals had significantly better neutralizing activity against various variants compared to unvaccinated individuals.
  • The findings suggest that vaccination, especially when followed by breakthrough infections, enhances the immune response and may inform strategies for optimizing vaccination against evolving viral strains.
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Background: There is little data about the performance of multiplex rapid antigen tests (RATs) on the detection of SARS-CoV-2, influenza A (Flu A), and influenza B (Flu B). This study is to evaluate the performance of Panbio COVID-19/Flu A&B rapid panel (Abbott Diagnostics, Korea) and analyze the factors influencing its sensitivity.

Methods: Nasopharyngeal swabs were collected and stored at the Korea University Anam hospital.

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Objective: Although adult spinal deformity (ASD) surgery aims to restore and maintain alignment, proximal junctional kyphosis (PJK) may occur. While existing scoring systems predict PJK, they predominantly offer a generalized 3-tier risk classification, limiting their utility for nuanced treatment decisions. This study seeks to establish a personalized risk calculator for PJK, aiming to enhance treatment planning precision.

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Objective: The risks of nonunion and subsidence are high in patients with bone density loss undergoing spinal fusion surgery. The internal application of recombinant human bone morphogenic protein 2 (rhBMP-2) in an interbody cage improves spinal fusion; however, related complications have been reported. Denosumab, a human monoclonal antibody targeting the receptor activator of nuclear factor kappa B ligand (RANKL), hinders osteoblast differentiation and function.

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Study Objective: Intraoperative electroencephalogram (EEG) patterns associated with postoperative delirium (POD) development have been studied, but the differences in EEG recordings between sevoflurane- and desflurane-induced anesthesia have not been clarified. We aimed to distinguish the EEG characteristics of sevoflurane and desflurane in relation to POD development.

Design And Patients: We collected frontal four-channel EEG data during the maintenance of anesthesia from 148 elderly patients who received sevoflurane (n = 77) or desflurane (n = 71); 30 patients were diagnosed with delirium postoperatively.

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We evaluated the performance of SARS-CoV-2 assays in the vaccinated group using receptor-binding domain antibody assays (RBD Ab assay), neutralizing antibody assay (nAb assay), and interferon-gamma release assay (IGR assay). We also compared the performance of the SARS-CoV-2 assays based on vaccine type in a large population. We collected 1851 samples from vaccinated individuals with vector, mix-and-match (MM), and mRNA vaccines.

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Bread staling adversely affects the quality of bread, but starch modification by enzymes can counteract this phenomenon. Glycogen branching enzymes (GBEs) used in this study were isolated from Deinococcus geothermalis (DgGBE), Escherichia coli (EcGBE), and Vibrio vulnificus (VvGBE). These enzymes were characterized and applied for starch dough modification to determine their role in improving bread quality.

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Objective: The objective of this study was to evaluate the accuracy of pedicle screw placement in patients undergoing percutaneous pedicle screw fixation with robotic guidance, using a newly developed 3-dimensional quantitative measurement system. The study also aimed to assess the clinical feasibility of the robotic system in the field of spinal surgery.

Methods: A total of 113 patients underwent pedicle screw insertion using the CUVIS-spine pedicle screw guide system (CUREXO Inc.

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Article Synopsis
  • Feeder cells are essential for keeping embryonic stem cells (ESCs) pluripotent by secreting proteins and growth factors, but using primary mouse embryonic fibroblasts (MEFs) has drawbacks like variability and labor-intensive preparation.
  • The study demonstrated that the STO cell line, derived from mouse embryonic fibroblasts, can effectively serve as a feeder layer for culturing pig ESCs, providing a more consistent alternative to MEFs.
  • By optimizing the density of STO cells, researchers found that pig ESCs showed similar pluripotent characteristics as those grown on primary MEFs, which is promising for applications in areas like preclinical research and cellular agriculture.
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Background: Therapeutic drug monitoring (TDM) of antifungal drugs is recommended. LC-MS/MS outperforms bioassay and high-performance liquid chromatography (HPLC) for TDM. In this study, we validated TDM for voriconazole, posaconazole, and itraconazole using HPLC-MS/MS with the multiple reaction monitoring (MRM) method.

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Objective: Nanog homeobox (NANOG) is a core transcription factor that contributes to pluripotency along with octamer binding transcription factor-4 (OCT4) and sex determining region-Y box-2 (SOX2). It is an epiblast lineage marker in mammalian pre-implantation embryos and exhibits a species-specific expression pattern. Therefore, it is important to understand the lineage of NANOG, the trophectoderm, and the primitive endoderm in the pig embryo.

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Inotodiol, a lanostane-type triterpenoid, and many phytochemicals from Chaga mushrooms have been investigated for various allergic diseases. However, the anti-aging and anti-inflammatory activities of inotodiol under different types of oxidative stress and the impact of inotodiol on collagen and hyaluronan synthesis have not been sufficiently studied. Lanostane triterpenoids-rich concentrate, which contained 10% inotodiol as major (inotodiol concentrate), was prepared from Chaga and compared with pure inotodiol in terms of anti-inflammatory activities on a human keratinocyte cell line, HaCaT cells, under various stimulations such as stimulation with ultraviolet (UV) B or tumor necrosis factor (TNF)-α.

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Cellular agriculture is an emerging research field of agribiotechnology that aims to produce agricultural products using stem cells, without sacrificing animals or cultivating crops. Cultivated meat, as a representative cellular product of cellular agriculture, is being actively researched due to global food insecurity, environmental, and ethical concerns. This review focuses on the application of stem cells, which are the seeds of cellular agriculture, for the production of cultivated meat, with emphasis on deriving and culturing muscle and adipose stem cells for imitating fresh meat.

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Background Context: The use of recombinant human bone morphogenetic proteins-2 (rhBMP-2) for spinal fusion has been reported to be effective. However, most studies have focused on posterolateral and anterior lumbar interbody fusion, and few have investigated posterior lumbar interbody fusion (PLIF).

Purpose: This study aimed to determine the effectiveness and safety of the delivery of Escherichia coli-derived rhBMP-2 (E.

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Fertilized embryos develop and move freely in the reproductive tract until implantation. Subsequently, the embryos continue to develop after attachment to the uterus. Because of the absence of the uterus, in vitro culturing of embryos is limited to a period of approximately a week.

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This multicenter (four institutions), randomized, investigator-masked, parallel-group clinical trial evaluated and compared the efficacy and safety of preservative-free and preserved brimonidine tartrate 0.15% in open-angle glaucoma and ocular hypertension. Sixty eyes of 60 patients with intraocular pressure (IOP) ≥ 15 mmHg diagnosed with open-angle glaucoma or ocular hypertension were randomized to preserved (n = 31) and preservative-free (n = 29) brimonidine groups.

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