• Proceedings of the Korean Society of Applied Pharmacology
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• 2001.11a
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• pp.100-100
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• 2001

Hypoxia is a pathophysiological condition that occurs during injury, ischemia, and stroke. Hypoxic stress induces the expression of genes associated with increased energy flux, including the glucose transporters Glutl and Glut3, several glycolytic enzymes, nitric oxide synthase, erythropoietin and vascular endothelial growth factor. Induction of these genes is mediated by a common basic helix-loop-helix PAS transcription complex, the hypoxia-inducible factor-l${\alpha}$ (HIF-1${\alpha}$)/ aryl hydrocarbon receptor nuclear translocator (ARNT). Insulin plays a central role in regulating metabolic pathways associated with energy storage and utilization. It triggers the conversion of glucose into glycogen and triglycerides and inhibits gluconeogenesis. Insulin also induced hypoxia-induced genes. However the underlying mechanism is unestablished. Here, we study the possibility that transcription factor HIF-1${\alpha}$ is involved in insulin-induced gene expression. We investigate the mechanism that regulates hypoxia-inducible gene expression In response to insulin We demonstrate that insulin increases the transcription of hypoxia- inducible gene. Insulin-induced transcription is not detected in Arnt defective cell lines. Under hypoxic condition, HIF- l${\alpha}$ stabilizes but does not under insulin treatment. Insulin-induced gene expression is inhibited by presence of PI-3 kinase inhibitor and Akt dominant negative mutant, whereas hypoxia-induced gene expression is not. ROS inhibitor differently affects insulin-induced gene expressions and hypoxia-induced gene expressions. Our results demonstrate that insulin also regulates hypoxia-inducible gene expression and this process is dependent on Arnt. However we suggest HIF-l${\alpha}$ is not involved insulin-induced gene expression and insulin- and hypoxia- induces same target genes via different signaling pathway.

• The Journal of Korean Physical Therapy
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• v.15 no.4
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• pp.199-207
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• 2003

This review describes the neurophathological mechanisms that are implicated in perinatal brain injury. Perinatal brain injury is the most important cause of morbidity and mortality to infants, often leading to spastic motor deficits, mental retardation, seizures, and learning impairments. The immature brain injury is usually caused by cerebral hypoxia-ischemia, hemorrhage, or infection. The important form of perinatal brain injury is the hypoxic-ischemic injury and the cerebral hemorrhage. The pathology of hypoxic-ischemic injury include delayed energy failure by mitochondrial dysfunction, neuronal excitotoxicity and vulnerability of white matter in developing brain. The immature brain has the fragile vascular bed of germinal matrix and can not effectively centralize their circulation. Therefore, the cerebral hemorrhage process is considered to be involved in the periventricular leukomalacia.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.17 no.3
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• pp.162-169
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• 2014

Purpose: To study temporal pattern of serum liver enzymes levels in newborns with hepatic injury associated with birth asphyxia (BA). Methods: Singleton term newborns with BA and ${\leq}72$ hours of age admitted to neonatal intensive care unit were prospectively enrolled. Term newborns with physiological jaundice and without BA were studied as controls. Serum liver enzymes were measured at <24 hours, 24-72 hours, and at 6-12 days of age for cases and at 1-6 days of age for controls. BA was defined by 1 minute Apgar score <7 or delayed or absent cry with hypoxic ischemic encephalopathy. BA-associated liver injury was defined as serum alanine aminotransferase (ALT) elevation beyond +2 standard deviation (ALT > +2 SD) above the mean of control subjects at any of the three time points. Results: Sixty controls and 62 cases were enrolled. Thirty-five cases (56%) developed BA-associated liver injury (ALT>81 IU/L). They had higher serum levels of ALT, aspartate aminotransferase, lactate dehydrogenase than the control infants, with peak at 24-72 hours. In controls, serum liver enzyme levels were significantly higher in appropriate-for-date (AFD) babies than small-for-date (SFD) babies. Serum enzyme pattern and extent of elevation were comparable between SFD and AFD babies. Degree of serum liver enzyme elevation had no relationship with severity of hypoxic encephalopathy. Conclusion: Serum liver enzyme elevation is common in BA; it peaks at 24-72 hours followed by a sharp decline by 6-12 days of age. Pattern and extent of enzyme elevation are comparable between SFD and AFD babies.

• Clinical and Experimental Pediatrics
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• v.64 no.4
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• pp.180-187
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• 2021

Background: Severe perinatal asphyxia results in multiple organ involvement, neonate hospitalization, and eventual death. Purpose: This study aimed to investigate the predictive factors of death in newborns with hypoxic-ischemic encephalopathy (HIE) receiving selective head cooling. Methods: This cross-sectional descriptive-retrospective study was conducted from 2013 to 2018 in Fatemieh Hospital of Hamadan and included 51 newborns who were admitted to the neonatal intensive care unit with a diagnosis of HIE. Selective head cooling for patients with moderate to severe HIE began within 6 hours of birth and continued for 72 hours. The required data for the predictive factors of death were extracted from the patients' medical files, recorded on a premade form, and analyzed using SPSS ver. 16. Results: Of the 51 neonates with moderate to severe HIE who were treated with selective head cooling, 16 (31%) died. There were significant relationships between death and the need for advanced neonatal resuscitation (P=0.002), need for mechanical ventilation (P=0.016), 1-minute Apgar score (P=0.040), and severely abnormal amplitude-integrated electroencephalography (a-EEG) (P=0.047). Multiple regression of variables or data showed that the need for advanced neonatal resuscitation was an independent predictive factor of death (P=0.0075) and severely abnormal a-EEG was an independent predictive factor of asphyxia severity (P=0.0001). Conclusion: All cases of neonatal death in our study were severe HIE (stage 3). Advanced neonatal resuscitation was an independent predictor of death, while a severely abnormal a-EEG was an independent predictor of asphyxia severity in infants with HIE.

• The Korean Journal of Physiology and Pharmacology
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• v.25 no.2
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• pp.97-109
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• 2021

Neonatal hypoxia/ischemia (H/I), injures white matter, results in neuronal loss, disturbs myelin formation, and neural network development. Neuroinflammation and oxidative stress have been reported in neonatal hypoxic brain injuries. We investigated whether Paeoniflorin treatment reduced H/I-induced inflammation and oxidative stress and improved white matter integrity in a neonatal rodent model. Seven-day old Sprague-Dawley pups were exposed to H/I. Paeoniflorin (6.25, 12.5, or 25 mg/kg body weight) was administered every day via oral gavage from postpartum day 3 (P3) to P14, and an hour before induction of H/I. Pups were sacrificed 24 h (P8) and 72 h (P10) following H/I. Paeoniflorin reduced the apoptosis of neurons and attenuated cerebral infarct volume. Elevated expression of cleaved caspase-3 and Bad were regulated. Paeoniflorin decreased oxidative stress by lowering levels of malondialdehyde and reactive oxygen species generation and while, and it enhanced glutathione content. Microglial activation and the TLR4/NF-κB signaling were significantly down-regulated. The degree of inflammatory mediators (interleukin 1β and tumor necrosis factor-α) were reduced. Paeoniflorin markedly prevented white matter injury via improving expression of myelin binding protein and increasing O1-positive olidgodendrocyte and O4-positive oligodendrocyte counts. The present investigation demonstrates the potent protective efficiency of paeoniflorin supplementation against H/I-induced brain injury by effectually preventing neuronal loss, microglial activation, and white matter injury via reducing oxidative stress and inflammatory pathways.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.6
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• pp.681-690
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• 1997

Loss of synaptic transmission and accumulation of extracellular $K^+([K^+]_O)$ are the key features in ischemic brain damage. Here, we examined the effects of several $K^+$channel modulators on the early ischemic changes in population spike (PS) and $[K^+]_o$ in the CA1 pyramidal layer of the rat hippocampal slice using electrophysiological techniques. After onset of anoxic aglycemia (AA), orthodromic field potentials decreased and disappeared in $3.3{\pm}0.22\;min$ $(mean{\pm}SEM,\;n=40)$. The hypoxic injury potential (HIP), a transient recovery of PS appeared at $6.0{\pm}0.25\;min$ (n=40) in most slices during AA and lasted for $3.3{\pm}0.43\;min$. $[K^+]_o$ increased initially at a rate of 0.43 mM/min (Phase 1) and later at a much faster rate (12.45 mM/min, Phase 2). The beginning of Phase 2 was invariably coincided with the disappearance of HIP. Among $K^+$ channel modulators tested such as 4-aminopyridine (0.03, 0.3 mM), tetraethylammonium (0.1 mM), NS1619 $(0.3{\sim}10\;{\mu}M)$, niflumic acid (0.1 mM), glibenclamide $(40\;{\mu}M)$, tolbutamide $(300\;{\mu}M)$ and pinacidil $(100\;{\mu}M)$, only 4-aminopyridine (0.3 mM) induced slight increase of $[K^+]_o$ during Phase 1. However, none of the above agents modulated the pattern of Phase 2 in $[K^+]_o$ in response to AA. Taken together, the experimental data suggest that 4-aminopyridine-sensitive $K^+$channels, large conductance $Ca^{2+}-activated$ $K^+$ channels and ATP-sensitive $K^+$ channels may not be the major contributors to the sudden increase of $[K^+]_o$ during the early stage of brain ischemia, suggesting the presence of other routes of $K^+$ efflux during brain ischemia.

• Journal of Chest Surgery
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• v.23 no.4
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• pp.646-653
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• 1990

Currently numerous methods are in use for myocardial protection from the ravages of ischemia and hypoxia. This study was designed to compare with FDP-GIK[Group II, n=8] and GIK cardioplegic solution[Group I, n=8] in ability of myocardial protection and was examined in the isolated working rat heart subjected to long period[120 min] of hypothermic[10 - 15K] ischemic arrest with multidose[every 30 min] cardioplegic infusion. During postischemic reperfusion period 20 min, hemodynamic functions[aortic flow, coronary flow, peak aortic pressure, cardiac output, heart rate], biochemical enzymatic & electrical activities were evaluated. The time from onset of reperfusion to the return of regular sinus rhythm was significantly reduced from 87$\pm$3 sec to 17$\pm$2 sec[P<0.05]. The postischemic recovery of aortic flow was better in the group II [95.1$\pm$3.3% of its preischemic control level] than in the Group I [75.4$\pm$6.8%] [P<0.05]. Cardiac output and stroke volume was also better in the group[91.3$\pm$1.6%, 89.4$\pm$2.6%, respectively] than in the Group I [79.1$\pm$3.7%, 77.0$\pm$4.8%, respectively] [P<0. 05]. Creatine kinase leakage was also significantly reduced from 33.8$\pm$4.9 IU /10 min / gm * dry weight to 15.4$\pm$3.6 IU /10 min /gm * dry weight[P<0.05]. It is suggested that adding FDP to GIK cardioplegic solution improves its ability to protect the heart against long period of hypoxic ischemia.

• Journal of Life Science
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• v.19 no.5
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• pp.598-606
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• 2009

Oxidative stress by free radicals is a major cause of neuronal cell death. Excitotoxicity in hypoxia/ischemia causes an increase in reactive oxygen species (ROS) and a loss of mitochondrial membrane potential (MMP), resulting in dysfunction of the mitochondria and cell death. Pinelliae Rhizoma (PR) is a traditional medicine for incipient stroke. We investigated the effects of PR Water-Extract on the modulation of ROS and MMP in a hypoxic model using cultured rat cortical cells. PR Water-Extract was added to the culture medium at various concentrations (0.25${\sim}$5, 5.0 ${\mu}g/ml$) on day in vitro 12(DIV12), given a hypoxic shock (2% $O_2$/5% $CO_2$, $37^{\circ}C$, 3 hr), and cell viability was assessed on DIV15 by Lactate Dehydrogenase Assay (LDH assays). PR Water-Extract showed a statistically significant effect on neuroprotection (10${\sim}$15% increase in viability; p<0.01) at 1.0 and 2.5 ${\mu}g/ml$ in normoxia and hypoxia. Measurement of ROS production by $H_2DCF-DA$ stainings showed that PR Water-Extract efficiently reduced the number and intensity of ROS-producing neurons, especially at 1 hr post shock and DIV15. When MMP was measured by JC-1 stainings, PR Water-Extract efficiently maintained high-energy charged mitochondria. These results indicate that PR Water-Extract protects neurons in hypoxia by preventing ROS production and preserving the cellular energy level.

• Journal of Trauma and Injury
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• v.33 no.3
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• pp.170-174
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• 2020

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is considered an emerging adjunct therapy for profound hemorrhagic shock, as it can maintain temporary stability until definitive repair of the injury. However, there is limited information about the use of this procedure in children. Herein, we report a case of REBOA in a pediatric patient with blunt trauma, wherein the preoperative deployment of REBOA played a pivotal role in damage control resuscitation. A 7-year-old male patient experienced cardiac arrest after a motor vehicle accident. After 30 minutes of cardiopulmonary resuscitation, spontaneous circulation was achieved. The patient was diagnosed with massive hemoperitoneum. REBOA was then performed under ongoing resuscitative measures. An intra-aortic balloon catheter was deployed above the supraceliac aorta, which helped achieved permissive hypotension while the patient was undergoing surgery. After successful bleeding control with small bowel resection for mesenteric avulsion, thorough radiologic evaluations revealed hypoxic brain injury. The patient died from deterioration of disseminated intravascular coagulation. Although the patient did not survive, a postoperative computed tomography scan revealed neither remaining intraperitoneal injury nor peripheral ischemia correlated with the insertion of a 7-Fr sheath. Hence, REBOA can be a successful bridge therapy, and this result may facilitate the further usage of REBOA to save pediatric patients with non-compressible torso hemorrhage.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.4
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• pp.427-433
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• 1998

In brain hypoxic-ischemia, an excess release of glutamate and a marked production of reactive oxygen species (ROS) occur in neuronal and non-neuronal cells. The present study investigated the effect of the biological antioxidants dihydrolipoic acid (DHLA) and lipoic acid (LA) on N-methyl-D-aspartate (NMDA)- and ROS-induced neurotoxicity in cultured rat cortical neurons. DHLA enhanced NMDA-evoked rises in intracellular calcium concentration ($[Ca^{2+}]_i$). In contrast, LA did not alter the NMDA-evoked calcium responses but decreased after a brief treatment of dithiothreitol (DTT), which possesses a strong reducing potential. Despite the modulation of NMDA receptor-mediated rises in $[Ca^{2+}]_i$, neither DHLA nor LA altered the NMDA receptor-mediated neurotoxicity, as assessed by measuring the amount of lactate dehydrogenase released from dead or injured cells. DHLA, but not LA, prevented the neurotoxicity induced by xanthine/xanthine oxidase-generated superoxide radicals. Both DHLA and LA decreased the glutathione depletion-induced neurotoxicity. The present data may indicate that biological antioxidants DHLA and LA protect neurons from ischemic injuries via scavenging oxygen free radicals rather than modulating the redox modulatory site(s) of NMDA receptor.