Publications by authors named "Yang-Hee Kim"

In the context of acute brain injuries, where zinc neurotoxicity and oxidative stress are acknowledged contributors to neuronal damage, we investigated the pivotal role of lysosomes as a potential protective mechanism. Our research commenced with an exploration of epidermal growth factor (EGF) and its impact on lysosomal dynamics, particularly its neuroprotective potential against zinc-induced cytotoxicity. Using primary mouse cerebrocortical cultures, we observed the rapid induction of EGFR endocytosis triggered by EGF, resulting in a transient increase in lysosomal vesicles.

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Research on islet replacement through the differentiation of functionally matured insulin-producing β-like cells for the treatment of diabetes presents a significant challenge. Neural signals in β cell differentiation significantly impact the pancreatic microenvironment in glucose metabolism, but they are not fully understood. In this study, isoproterenol, a β adrenoreceptor agonist, was introduced into pancreatic progenitor cells, derived from human pluripotent stem cells in vitro, undergoing endocrine differentiation, using 2-dimensional (2D) and 3-dimensional (3D) differentiation protocols.

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  • Microbial fermentation is key for producing essential goods sustainably, with a focus on amino acid production from engineered organisms.
  • This study tested the safety of biomass products from bioengineered microorganisms using the AMES test and oral toxicity test in rats, finding no harmful effects at the doses tested.
  • The results support the potential use of these biomass products as safe feed materials, emphasizing the need for thorough safety assessments and adherence to regulatory standards in biotechnological applications.
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  • Decellularized tissues, which keep the structure of natural tissues, can help with tissue regeneration, but using human bone for this is still not well-studied.
  • Researchers found that changing the size of the bone powder and how long they digested it influenced the amount of proteins in the hydrogels, making them stronger and better.
  • When human bone marrow cells were grown on the best hydrogels, they grew into bone cells more effectively, showing these materials could be good for helping bones heal.
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Mesenchymal stromal stem cells (MSCs) or skeletal stem cells (SSCs) play a major role in tissue repair due to their robust ability to differentiate into osteoblasts, chondrocytes, and adipocytes. Complex cell signaling cascades tightly regulate this differentiation. In osteogenic differentiation, Runt-related transcription factor 2 (RUNX2) and ALP activity are essential.

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  • * A study was conducted on pigs to evaluate the potential risks of using L-tryptophan as a feed additive, focusing on general toxicity and EMS-related symptoms.
  • * Results showed no toxic effects or EMS symptoms in the pigs, indicating that L-tryptophan and its impurities do not pose safety concerns, allowing its continued use in swine diets throughout all growth stages.
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Unlabelled: Autograft or metal implants are routinely used in skeletal repair. However, they fail to provide long-term clinical resolution, necessitating a functional biomimetic tissue engineering alternative. The use of native human bone tissue for synthesizing a biomimetic material ink for three-dimensional (3D) bioprinting of skeletal tissue is an attractive strategy for tissue regeneration.

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Over the last two decades, quantum-dot light-emitting diodes (QLEDs), also known as quantum dot (QD) electroluminescent devices, have gained prominence in next-generation display technologies, positioning them as potential alternatives to organic light-emitting diodes. Nonetheless, challenges persist in enhancing key device performances such as efficiency and lifetime, while those of blue QLEDs lag behind compared with green and red counterparts. In this Perspective, we discuss key factors affecting the photoluminescence characteristics of environmentally benign blue-emissive ternary ZnSeTe QDs, including composition, core/shell heterostructure, and surface ligand.

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Pulmonary arterial hypertension (PAH) is a severe medical condition characterized by elevated blood pressure in the pulmonary arteries. Nitric oxide (NO) is a gaseous signaling molecule with potent vasodilator effects; however, inhaled NO is limited in clinical practice because of the need for tracheal intubation and the toxicity of high NO concentrations. In this study, inhalable NO-releasing microspheres (NO inhalers) are fabricated to deliver nanomolar NO through a nebulizer.

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  • The study investigates the buildup of misfolded proteins in neurodegenerative diseases (NDs) and aims to find common molecular mechanisms across these conditions using a model called MLnet.
  • By applying this model to diseases like Alzheimer's and Huntington's, researchers identified several insulin pathway proteins, such as Akt1, as common modifiers.
  • Validation in lab tests showed that activating Akt1 improved cell viability in NDs and enhanced memory and reduced anxiety in mouse models of Alzheimer's, suggesting MLnet is a useful tool for discovering shared therapeutic targets across different diseases.
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Clay nanoparticles, in particular synthetic smectites, have generated interest in the field of tissue engineering and regenerative medicine due to their utility as cross-linkers for polymers in biomaterial design and as protein release modifiers for growth factor delivery. In addition, recent studies have suggested a direct influence on the osteogenic differentiation of responsive stem and progenitor cell populations. Relatively little is known however about the mechanisms underlying nanoclay bioactivity and in particular the cellular processes involved in nanoclay-stem cell interactions.

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  • * The EMS outbreak was linked to impurities in L-tryptophan from certain manufacturing processes, not the substance itself.
  • * A study with broiler chickens found no toxic effects or EMS-related symptoms from L-tryptophan in meat, suggesting that L-tryptophan and its impurities are safe as feed additives.
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  • * EMS can affect various organ systems, leading to inflammation in muscles, skin, and lungs, and its association with L-tryptophan supplements has become controversial.
  • * Research has explored the connection between impurities in L-tryptophan products and EMS, but studies have yet to produce clear conclusions on the relationship.
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: With the emergence of breast implant-associated anaplastic large cell lymphoma (BIA-ALCL), it has become necessary to identify the implant shell type patients have received. Therefore, an immediate, reliable method for identifying a breast implant shell type is essential. Evidence-based research and applying a real-world technique that identifies the surface topographic information of the inserted breast implants, without surgery, has become of paramount importance for breast implant physicians.

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Aucubin is an iridoid glycoside that displays various pharmacological actions including antioxidant activity. However, there are few reports available on the neuroprotective effects of aucubin against ischemic brain injury. Thus, the aim of this study was to investigate whether aucubin protected against damage to hippocampal function induced by forebrain ischemia-reperfusion injury (fIRI) in gerbils, and to examine whether aucubin produced neuroprotection in the hippocampus against fIRI and to explore its mechanisms by histopathology, immunohistochemistry, and Western analysis.

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Myriad lung diseases are life threatening and macrophages play a key role in both physiological and pathological processes. Macrophages have each pro-/anti-inflammatory phenotype, and each lung disease can be aggravated by over-polarized macrophage. Therefore, development of a method capable of mediating the macrophage phenotype is one of the solutions for lung disease treatment.

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Multi-organ dysfunction following cardiac arrest is associated with poor outcome as well as high mortality. The kidney, one of major organs in the body, is susceptible to ischemia and reperfusion; however, there are few studies on renal ischemia and reperfusion injury (IRI) following the return of spontaneous circulation (ROSC) after cardiac arrest. Risperidone, an atypical antipsychotic drug, has been discovered to have some beneficial effects beyond its original effectiveness.

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Cardiac arrest (CA) and return of spontaneous circulation (ROSC), a global ischemia and reperfusion event, lead to neuronal damage and/or death in the spinal cord as well as the brain. Hypothermic therapy is reported to protect neurons from damage and improve hindlimb paralysis after resuscitation in a rat model of CA induced by asphyxia. In this study, we investigated roles of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) in the lumbar spinal cord protected by therapeutic hypothermia in a rat model of asphyxial CA.

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Background: Ischemia and reperfusion injury in the brain triggers cognitive impairment which are accompanied by neuronal death, loss of myelin sheath and decline in neurotransmission. In this study, we investigated whether therapeutic administration of Brain Factor-7® (BF-7®; a silk peptide) in ischemic gerbils which were developed by transient (five minutes) ischemia and reperfusion in the forebrain (tFI/R) improved cognitive impairment.

Methods: Short-term memory and spatial memory functions were assessed by passive avoidance test and Barnes maze test, respectively.

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  • * This study focuses on creating a new analytical method to detect impurities in meat products quickly using a technique called LC-MS/MS.
  • * The method successfully identifies four specific impurities in just 5 minutes, with high sensitivity and no interference from other substances in the meat, achieving detection limits below 11.2 μg/kg.
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Research reports using animal models of ischemic insults have demonstrated that oxcarbazepine (a carbamazepine analog: one of the anticonvulsant compounds) extends neuroprotective effects against cerebral or forebrain injury induced by ischemia and reperfusion. However, research on protective effects against ischemia and reperfusion cerebellar injury induced by cardiac arrest (CA) and the return of spontaneous circulation has been poor. Rats were assigned to four groups as follows: (Groups 1 and 2) sham asphyxial CA and vehicle- or oxcarbazepine-treated, and (Groups 3 and 4) CA and vehicle- or oxcarbazepine-treated.

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  • A study assessed the safety of L-tryptophan, produced through fermentation, by giving different doses (0, 500, 1000, 2000 mg/kg/day) to male and female Sprague-Dawley rats for 90 days.
  • No negative health effects were found in any of the rats, even at the highest dose, and this was confirmed during a 4-week recovery period following the treatment.
  • Histological tests also showed no significant changes related to eosinophilia-myalgia syndrome, leading to the conclusion that the dried L-tryptophan product is safe for use as a feed additive.
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AMP-activated protein kinase (AMPK) is necessary for maintaining a positive energy balance and essential cellular processes such as glycolysis, gene transcription, glucose uptake, and several other biological functions. However, brain injury-induced energy and metabolic stressors, such as cerebral ischemia, increase AMPK phosphorylation. Phosphorylated AMPK contributes to excitotoxicity, oxidative, and metabolic problems.

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The stimulation of autophagy or lysosomes has been considered therapeutic for neurodegenerative disorders because the accumulation of misfolded proteins is commonly observed in the brains of individuals with these diseases. Although zinc is known to play critical roles in the functions of lysosomes and autophagy, the mechanism behind this regulatory relationship remains unclear. Therefore, in this study, we examined which mechanism is involved in zinc-mediated activation of autophagy and lysosome.

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Isolating a large quantity of high-quality human islets is a prerequisite for diabetes research. Human islets are typically isolated from the pancreases of brain-dead donors, making research difficult due to low availability. Pancreas tissue discarded after surgical resection may be a good alternative source of islet cells.

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