Publications by authors named "Choong-Hyun Lee"

In the current study, we investigated the effects and action mechanism of integrin a3b1 in modulating non-small cell lung cancer (NSCLC) growth and progression. Reduced expression of integrin a3 by RNA silencing in p53 wild-type A549 NSCLC cells inhibits cell migration and invasion, compared with those in control cells. These anti-migratory and anti-invasive properties in integrin a3-silenced cells were associated with epithelial cadherin (E-cadherin) distribution at cell-cell contacts, and these effects require the activation of p70 S6 kinase (p70S6K) as evidenced by treatment with rapamycin.

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Article Synopsis
  • Ischemia and reperfusion (IR) lead to oxidative stress and excitotoxicity, major factors in neuronal death in the brain, and hyperthermia worsens this damage.
  • A study conducted on gerbils showed that hyperthermic conditions resulted in earlier neuronal death after IR injury compared to normothermic conditions, with significant increases in oxidative stress markers.
  • The research indicated that hyperthermia amplifies neuronal damage in the hippocampal CA1 region by enhancing oxidative stress and excitotoxicity, as evidenced by changes in various protein levels and cell responses.
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Astrocytes are highly activated following brain injuries, and their activation influences neuronal survival. Additionally, SOX9 expression is known to increase in reactive astrocytes. However, the role of SOX9 in activated astrocytes following ischemic brain damage has not been clearly elucidated yet.

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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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Background: A gerbil model of ischemia and reperfusion (IR) injury in the forebrain has been developed for studies on mechanisms, prevention and therapeutic strategies of IR injury in the forebrain. Pycnogenol® (PYC), a standardized extract of French maritime pine tree ( Aiton) has been exploited as an additive for dietary supplement. In the present study, we investigated the neuroprotective effects of post-treatment with PYC and its therapeutic mechanisms in gerbils.

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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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Laminarin is a polysaccharide isolated from brown marine algae and has a wide range of bioactivities, including immunoregulatory and anti-inflammatory properties. However, the effects of laminarin on atopic dermatitis have not been demonstrated. This study investigated the potential effects of topical administration of laminarin using a Balb/c mouse model of oxazolone-induced atopic dermatitis-like skin lesions.

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Article Synopsis
  • Neuronal death occurs selectively in certain brain regions post-ischemic events, and is closely linked with astrogliosis, which alters astrocyte molecular expression and structure.
  • This study used gerbil models to explore the effects of varying degrees of transient forebrain ischemia (mild vs. severe) on neuronal and astrocyte damage, finding more severe neuronal death and astrogliosis in cases of greater ischemic insult.
  • Results show that the damage to astrocytes, particularly their endfeet, is more pronounced in severe ischemia, indicating that astrogliosis may be influenced by the level of ischemic injury, which correlates with neuronal damage.
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Astaxanthin is a powerful biological antioxidant and is naturally generated in a great variety of living organisms. Some studies have demonstrated the neuroprotective effects of ATX against ischemic brain injury in experimental animals. However, it is still unknown whether astaxanthin displays neuroprotective effects against severe ischemic brain injury induced by longer (severe) transient ischemia in the forebrain.

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The hippocampus has a different vulnerability to ischemia according to the subfields CA1 to CA3 (initials of cornu ammonis). It has been reported that body temperature changes during ischemia affect the degree of neuronal death following transient ischemia. Hypoxia‑inducible factor 1α (HIF‑1α) plays a key role in regulating cellular adaptation to low oxygen conditions.

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Stiripentol is an anti-epileptic drug for the treating of refractory status epilepticus. It has been reported that stiripentol can attenuate seizure severity and reduce seizure-induced neuronal damage in animal models of epilepsy. The objective of the present study was to investigate effects of post-treatment with stiripentol on cognitive deficit and neuronal damage in the cornu ammonis 1 (CA1) region of the hippocampus proper following transient ischemia in the forebrain of gerbils.

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Herein, entecavir-3-palmitate (EV-P), an ester prodrug of entecavir (EV), was employed as a model drug, and the effect of drug particle size on in vivo pharmacokinetic profiles and local inflammatory responses, and those associations were evaluated following intramuscular (IM) injection. EV-P crystals with different median diameters (0.8, 2.

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Inadequate activation of cell cycle proteins including cyclin D1 and cdk4 is involved in neuronal cell death induced by diverse pathological stresses, including transient global brain ischemia. The neuroprotective effect of ischemic preconditioning is well-established, but the underlying mechanism is still unknown. In this study, we examined changes in cyclin D1, cdk4, and related molecules in cells or neurons located in Cornu Ammonis 1 (CA1) of gerbil hippocampus after transient ischemia for 5 min (ischemia and reperfusion) and investigated the effects of IPC on these molecules after ischemia.

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Korean red pine () belongs to the Genus and its bark contains a great amount of naturally occurring phenolic compounds. Until now, few studies have been conducted to assess the neuroprotective effects of bark extract against brain ischemic injury. The aim of this study was to investigate the neuroprotective effects of pre-treatment with the extract in the hippocampus following 5-min transient forebrain ischemia in gerbils.

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Tumor necrosis factor (TNF)‑α and TNF receptor 1 (TNF‑R1) play diverse roles in modulating the neuronal damage induced by cerebral ischemia. The present study compared the time‑dependent changes of TNF‑α and TNF‑R1 protein expression levels in the hippocampal subfield cornu ammonis 1 (CA1) between adult and young gerbils following transient forebrain ischemia (tFI), via western blot and immunohistochemistry analyses. In adult gerbils, delayed neuronal death of pyramidal neurons, the principal neurons in CA1, was recorded 4 days after tFI; however, in young gerbils, delayed neuronal death was recorded 7 days after tFI.

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Transient ischemia in the brain causes blood-brain barrier (BBB) breakdown and dysfunction, which is related to ischemia-induced neuronal damage. Leakage of plasma proteins following transient ischemia is one of the indicators that is used to determine the extent of BBB dysfunction. In this study, neuronal damage/death, leakage of albumin and IgG, microgliosis, and inflammatory cytokine expression were examined in the hippocampal CA1 region, which is vulnerable to transient ischemia, following 5-min (mild) and 15-min (severe) ischemia in gerbils induced by transient common carotid arteries occlusion (tCCAo).

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Salicin is a major natural compound of willow bark and displays diverse beneficial biological properties, such as antioxidant activity. However, little information available for the neuroprotective potential of salicin against ischemic brain injury has been reported. Thus, this study was performed to investigate the neuroprotective potential of salicin against ischemia and reperfusion (IR) injury and its mechanisms in the hippocampus using a gerbil model of 5-min transient ischemia (TI) in the forebrain, in which a massive loss (death) of pyramidal neurons cells occurred in the subfield Cornu Ammonis 1 (CA1) among the hippocampal subregions (CA1-3) at 5 days after TI.

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It has been studied that the damage or death of neurons in the hippocampus is different according to hippocampal subregions, cornu ammonis 1-3 (CA1-3), after transient ischemia in the forebrain, showing that pyramidal neurons located in the subfield CA1 (CA1) are most vulnerable to this ischemia. Hyperthermia is a proven risk factor for brain ischemia and can develop more severe and extensive brain damage related with mortality rate. It is well known that heme oxygenase-1 (HO-1) activity and expression is increased by various stimuli in the brain, including hyperthermia.

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Nakai root contains decursin which exerts beneficial properties such as anti-amnesic and anti-inflammatory activities. Until now, however, the neuroprotective effects of decursin against transient ischemic injury in the forebrain have been insufficiently investigated. Here, we revealed that post-treatment with decursin and the root extract saved pyramidal neurons in the hippocampus following transient ischemia for 5 min in gerbil forebrain.

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It has been reported that CD200 (Cluster of Differentiation 200), expressed in neurons, regulates microglial activation in the central nervous system, and a decrease in CD200 expression causes an increase in microglial activation and neuronal loss. The aim of this study was to investigate time-dependent changes in CD200 expression in the hippocampus proper (CA1, 2, and 3 fields) after transient forebrain ischemia for 5 min in gerbils. In this study, 5-min ischemia evoked neuronal death (loss) of pyramidal neurons in the CA1 field, but not in the CA2/3 fields, at 5 days postischemia.

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Autonomic dysfunction in the central nervous system (CNS) can cause death after recovery from a cardiac arrest (CA). However, few studies on histopathological changes in animal models of CA have been reported. In this study, we investigated the prevalence of neuronal death and damage in various brain regions and the spinal cord at early times after asphyxial CA and we studied the relationship between the mortality rate and neuronal damage following hypothermic treatment after CA.

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It is questionable whether intermittent fasting (IF) protects against brain ischemic injury. This study examined whether IF increased anti-inflammatory cytokines and protected neurons from ischemia-reperfusion injury in the gerbil hippocampus. Gerbils were subjected to 1-day alternating fasting as IF for 1, 2, or 3 months and assigned to sham or 5 min of transient ischemia.

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Neuroinflammation is a primary characteristic of the aging brain. During normal aging, macrophage inflammatory protein‑3α (MIP‑3α) and its receptor C‑C chemokine receptor type 6 (CCR6) serve pivotal roles in the neuroinflammatory process in the brain. The aim of the present study was to investigate age‑dependent alterations in the immunoreactivity of MIP‑3α and CCR6 in the gerbil hippocampus at postnatal month (PM) 1, 6, 12 and 24 via immunohistochemistry.

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Monocarboxylate transporter 4 (MCT4) is a high‑capacity lactate transporter in cells and the alteration in MCT4 expression harms cellular survival. The present study investigated whether hypothermia affects tumor necrosis factor‑α (TNF‑α) and MCT4 immunoreactivity in the subfield cornu ammonis 1 (CA1) following cerebral ischemia/reperfusion (IR) in gerbils. Hypothermia was induced for 30 min before and during ischemia.

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