Publications by authors named "Sooyeon Kang"

Cryopreservation in cryovials extends cell storage at low temperatures, and advances in organoid cryopreservation improve reproducibility and reduce generation time. However, cryopreserving human organoids presents challenges due to the limited diffusion of cryoprotective agents (CPAs) into the organoid core and the potential toxicity of these agents. To overcome these obstacles, we developed a cryopreservation technique using a pillar plate platform.

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Despite the potential toxicity of commercial chemicals to the development of the nervous system (known as developmental neurotoxicity or DNT), conventionalcell models have primarily been employed for the assessment of acute neuronal toxicity. On the other hand, animal models used for the assessment of DNT are not physiologically relevant due to the heterogenic difference between humans and animals. In addition, animal models are low-throughput, time-consuming, expensive, and ethically questionable.

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The liver's role in the biotransformation of chemicals is critical for both augmented toxicity and detoxification. However, there has been a significant lack of effort to integrate biotransformation into in vitro neurotoxicity testing. Traditional in vitro neurotoxicity testing systems are unable to assess the qualitative and quantitative differences between parent chemicals and their metabolites as they would occur in the human body.

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Cryopreservation in cryovials extends cell storage at low temperatures, and advances in organoid cryopreservation improve reproducibility and reduce generation time. However, cryopreserving human organoids presents challenges due to the limited diffusion of cryoprotective agents (CPAs) into the organoid core and the potential toxicity of these agents. To overcome these obstacles, we developed a cryopreservation technique using a pillar plate platform.

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Enzyme-induced self-assembly (EISA) is a recently developed nanotechnology technique in which small molecules are induced by cellular enzymes self-assembling into nanostructures inside cancer cells. This technique can boost the efficacy of chemotherapy drugs by avoiding drug efflux, inhibiting the cells' DNA repair mechanisms, and targeting the mitochondria. In this work, we study the self-assembly of a short peptide and its fluorescence analogue induced by Eyes absent (EYA) tyrosine phosphatases to boost the efficacy of doxorubicin (DOX) therapy in drug-resistant types of breast cancer cells, MDA-MB-231 and MCF-7.

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Static three-dimensional (3D) cell culture has been demonstrated in ultralow attachment well plates, hanging droplet plates, and microtiter well plates with hydrogels or magnetic nanoparticles. Although it is simple, reproducible, and relatively inexpensive, thus potentially used for high-throughput screening, statically cultured 3D cells often suffer from a necrotic core due to limited nutrient and oxygen diffusion and waste removal and have a limited -like tissue structure. Here, we overcome these challenges by developing a pillar/perfusion plate platform and demonstrating high-throughput, dynamic 3D cell culture.

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Human liver organoids (HLOs) hold significant potential for recapitulating the architecture and function of liver tissues . However, conventional culture methods of HLOs, forming Matrigel domes in 6-/24-well plates, have technical limitations such as high cost and low throughput in organoid-based assays for predictive assessment of compounds in clinical and pharmacological lab settings. To address these issues, we have developed a unique microarray 3D bioprinting protocol of progenitor cells in biomimetic hydrogels on a pillar plate with sidewalls and slits, coupled with a clear bottom, 384-deep well plate for scale-up production of HLOs.

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Human liver organoids (HLOs) differentiated from embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs), and adult stem cells (ASCs) can recapitulate the structure and function of human fetal liver tissues, thus being considered as a promising tissue model for liver diseases and predictive compound screening. However, the adoption of HLOs in drug discovery faces several technical challenges, which include the lengthy differentiation process with multiple culture media leading to batch-to-batch variation, short-term maintenance of hepatic functions post-maturation, low assay throughput due to Matrigel dissociation and HLO transfer to a microtiter well plate, and insufficient maturity levels compared to primary hepatocytes. To address these issues, expandable HLOs (Exp-HLOs) derived from human iPSCs were generated by optimizing differentiation protocols, which were rapidly printed on a 144-pillar plate with sidewalls and slits (144PillarPlate) and dynamically cultured for up to 20 days into differentiated HLOs (Diff-HLOs) in a 144-perfusion plate with perfusion wells and reservoirs (144PerfusionPlate) for organoid culture and analysis.

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Human liver organoids (HLOs) hold significant potential for recapitulating the architecture and function of liver tissues . However, conventional culture methods of HLOs, forming Matrigel domes in 6-/24-well plates, have technical limitations such as high cost and low throughput in organoid-based assays for predictive assessment of compounds in clinical and pharmacological lab settings. To address these issues, we have developed a unique microarray 3D bioprinting protocol of progenitor cells in biomimetic hydrogels on a pillar plate with sidewalls and slits, coupled with a clear bottom, 384-deep well plate for scale-up production of HLOs.

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Despite the potential toxicity of commercial chemicals to the development of the nervous system (known as developmental neurotoxicity or DNT), conventional cell models have primarily been employed for the assessment of acute neuronal toxicity. On the other hand, animal models used for the assessment of DNT are not physiologically relevant due to the heterogenic difference between humans and animals. In addition, animal models are low-throughput, time-consuming, expensive, and ethically questionable.

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Despite the fact that biotransformation in the liver plays an important role in the augmented toxicity and detoxification of chemicals, relatively little efforts have been made to incorporate biotransformation into in vitro neurotoxicity testing. Conventional in vitro systems for neurotoxicity tests lack the capability of investigating the qualitative and quantitative differences between parent chemicals and their metabolites in the human body. Therefore, there is a need for an in vitro toxicity screening system that can incorporate hepatic biotransformation of chemicals and predict the susceptibility of their metabolites to induce neurotoxicity.

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Human organoids have the potential to revolutionize in vitro disease modeling by providing multicellular architecture and function that are similar to those in vivo. This innovative and evolving technology, however, still suffers from assay throughput and reproducibility to enable high-throughput screening (HTS) of compounds due to cumbersome organoid differentiation processes and difficulty in scale-up and quality control. Using organoids for HTS is further challenged by the lack of easy-to-use fluidic systems that are compatible with relatively large organoids.

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The aim of this study was to compare the outcomes of preperitoneal pelvic packing (PPP) and angioembolization (AE) for patients with equivocal vital signs after initial resuscitation. This single-centered retrospective study included information from the database of a regional trauma center from April 2014 to December 2022 for patients with pelvic fractures with a systolic blood pressure of 80-100 mmHg after initial fluid resuscitation. The patients' characteristics, outcomes, and details of AE after resuscitative endovascular balloon occlusion of the aorta (REBOA) placed in zone III were collected.

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Article Synopsis
  • Human organoids show promise in disease modeling by mimicking multicellular structures and functions of actual organs.
  • Current challenges in using organoids for high-throughput screening (HTS) include complex differentiation processes and the need for reliable fluidic systems.
  • The development of a new "microarray 3D bioprinting" technology with special plates facilitates easy organoid culture and functional assays, making it compatible with existing drug discovery tools.
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Static three-dimensional (3D) cell culture has been demonstrated in ultralow attachment well plates, hanging droplet plates, and microtiter well plates with hydrogels or magnetic nanoparticles. Although it is simple, reproducible, and relatively inexpensive, thus potentially used for high-throughput screening, statically cultured 3D cells often suffer from the necrotic core due to limited nutrient and oxygen diffusion and waste removal and have limited -like tissue structure. Here, we overcome these challenges by developing a pillar/perfusion plate platform and demonstrating high-throughput, dynamic 3D cell culture.

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Background: Understanding the changes in characteristics of patients who visited trauma centres during the coronavirus disease 2019 (COVID-19) pandemic is important to facilitate aneffective response. This retrospective study was conducted to analyse differences in the characteristics and outcomes of patients who visited our trauma centre between pre-COVID-19 and COVID-19 eras.

Methods: Medical data of trauma patients enrolled in the Korean trauma database from 1 January 2018 to 31 August 2021 were collected.

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In this study, we have examined the anticancer effects of SH005S7 on MET-amplified and (HCC827GR) NSCLC cells and their primary HCC827 cells. , first of all, cell viability and colony formation assay confirmed the growth inhibitory effects of SH005S7 on both cells. Second, SH005S7 inactivated EGFR-related multiple cell signaling, which was associated with a marked decrease in the constitutive phosphorylation of EGFR, HER3, MET, AKT, and ERK.

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Background and objectives: Ocular ultrasound is a core application of point-of-care ultrasound (POCUS) to assist physicians in promptly identifying various ocular diseases at the bedside; however, hands-on POCUS training is challenging during a pandemic. Materials and Methods: A randomized controlled non-inferiority trial was conducted in an academic emergency department from October 2020 to April 2021. Thirty-two participants were randomly assigned to one of two groups.

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Neurotoxicity potential of compounds by inhibition of ion channels and efflux transporters has been studied traditionally using two-dimensionally (2D) cultured cell lines such as CHO and HEK-293 overexpressing the protein of interest. However, these approaches are time consuming and do not recapitulate the activity of ion channels and efflux transporters indigenously expressed in neural stem cells (NSCs) in vivo. To overcome these issues, we established ion channel and transporter assays on a 384-pillar plate with three-dimensionally (3D) cultured ReNcell VM and demonstrated high-throughput measurement of ion channel and transporter activity.

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: Point-of-care ultrasound (POCUS) is a useful tool that helps clinicians properly treat patients in emergency department (ED). This study aimed to evaluate the impact of specific interventions on the use of POCUS in the ED. : This retrospective study used an interrupted time series analysis to assess how interventions changed the use of POCUS in the emergency department of a tertiary medical institute in South Korea from October 2016 to February 2021.

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Assessing the neurotoxicity of test chemicals has typically been performed using two-dimensionally (2D)-cultured neuronal cell monolayers and animal models. The in vitro 2D cell models are simple and straightforward compared to animal models, which have the disadvantage of being relatively low throughput, expensive, and time consuming. Despite their extensive use in this area of neurotoxicology research, both models often do not accurately recapitulate human outcomes.

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The assessment of neurotoxicity has been performed traditionally with animals. However, in vivo studies are highly expensive and time-consuming, and often do not correlate to human outcomes. Thus, there is a need for cost-effective, high-throughput, highly predictive alternative in vitro test methods based on early markers of mechanisms of toxicity.

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A variety of oxidative and conjugative enzymes are involved in the metabolism of compounds including drugs, which can be converted into toxic metabolites by Phase I drug-metabolizing enzymes (DMEs), such as the cytochromes P450 (CYP450s), and/or detoxified by Phase II DMEs, such as UDP-glucuronosyltransferases (UGTs), sulfotransferases (SULTs), and glutathione S-transferases (GSTs). Traditionally, primary hepatocytes containing a complete set of DMEs have been widely used as a gold standard to assess metabolism-induced compound toxicity. However, primary hepatocytes are expensive, have high donor variability in expression levels of DMEs, and rapidly lose liver-specific functions when the cells are maintained under standard in vitro cell culture conditions over time.

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Dysregulated lipid metabolism is a prominent feature of prostate cancers (PCas); several enzymes involved in lipid accumulation are highly expressed. Here, we elucidated efficacy of TJ001, a traditional herbal decoction, in inhibiting lipogenesis. TJ001 had significant cytotoxicity against DU145 but not PC3 and LNCaP cells and, similarly, TJ001 markedly AMPK phosphorylation only in DU145 cells.

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High-content imaging (HCI) assays on two-dimensional (2D) cell cultures often do not represent in vivo characteristics accurately, thus reducing the predictability of drug toxicity/efficacy in vivo. On the other hand, conventional 3D cell cultures are relatively low throughput and possess difficulty in cell imaging. To address these limitations, a miniaturized 3D cell culture has been developed on a micropillar/microwell chip platform with human cells encapsulated in biomimetic hydrogels.

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