• Molecules and Cells
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• v.27 no.2
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• pp.243-250
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• 2009

Recent studies suggest a novel role of $HIF-1{\alpha}$ under nonhypoxic conditions, including antibacterial and antiviral innate immune responses. However, the identity of the pathogen-associated molecular pattern which triggers $HIF-1{\alpha}$ activation during the antiviral response remains to be identified. Here, we demonstrate that cellular administration of double-stranded nucleic acids, the molecular mimics of viral genomes, results in the induction of $HIF-1{\alpha}$ protein level as well as the increase in $HIF-1{\alpha}$ target gene expression. Whole-genome DNA microarray analysis revealed that double-stranded nucleic acid treatment triggers induction of a number of hypoxia-inducible genes, and induction of these genes are compromised upon siRNA-mediated $HIF-1{\alpha}$ knock-down. Interestingly, $HIF-1{\alpha}$ knock-down also resulted in down-regulation of a number of genes involved in antiviral innate immune responses. Our study demonstrates that $HIF-1{\alpha}$ activation upon nucleic acid-triggered antiviral innate immune responses plays an important role in regulation of genes involved in not only hypoxic response, but also immune response.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.1
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• pp.117-125
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• 2007

Neuronal ischemia is a pathological process caused by a lack of oxygen (anoxia) and glucose (hypoglycemia), resulting in neuronal death. It is believed that apoptosis is one of the mechanisms involved in ischemic cell death. Neuronal apoptosis is a process characterized by nuclear DNA fragmentation, changes of plasma membrane organization. To elucidate the mechanism of neuronal death following ischemic insult and to develop neuroprotective effects of Daebowonjeon(DBWJ) against ischemic damage, in vitro models are used. In vitro models of cell death have been devloped with pheochromocytoma (PC12) cell, which have become widely used as neuronal models of oxidative stress, trophic factor, serum deprivation and chemical hypoxia. Using a special ischemic device and PC12 cultures, we investigated an in vitro model of ischemia based on combined Oxygen and Glucose Deprivation (OGD) insult, followed by reoxygenation, mimicking the pathological conditions of ischemia. In this study, Daebowonjeon rescued PC12 cells from Oxygen-Glucose Deprivation (OGD)-induced cell death in a dose-dependent manner The nuclear staining of PC12 cells clearly showed that DBWJ attenuated nuclear condensation and fragmentation which represent typical neuronal apoptotic characteristics. DBWJ also prevents the LDH release and induction of Hypoxia Inducing Factor (HIF)-1 by OGD-exposed PC12 cells. Furthermore, DBWJ reduced the activation of polyADP-ribose polymerase (PARP) by OGO-exposed PC12 cells. These results suggest that apoptosis is an important characteristic of OGD-induced neuronal death and that oriental medicine, such as DBWJ, may prevent PC12 cell from OG D-induced neuronal death by inhibiting the apoptotic process.

• Journal of Nutrition and Health
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• v.48 no.5
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• pp.451-456
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• 2015

Purpose: Neuronal apoptotic events induced by aging and hypoxic/ischemic conditions is an important risk factor in neurodegenerative diseases such as ischemia stroke and Alzheimer's disease. The peel of Citrus sunki Hort. ex Tanaka has long been used as a traditional medicine, based on multiple biological activities including anti-oxidant, anti-inflammation, and anti-obesity. In the current study, we examined the actions of fermented C. sunki peel extract against cobalt chloride ($CoCl_2$)-mediated hypoxic death in human neuroblastoma SH-SY5Y cells. Methods: Cell viability was measured by trypan blue exclusion. Expression of apoptosis related proteins and release of cytochrome c were detected by western blot. Production of intracellular reactive oxygen species (ROS) and apoptotic morphology were examined using 2',7'-dichlorofluorescin diacetate (DCF-DA) and 4',6-diamidino-2-phenylindole (DAPI) staining. Results: Exposure to $CoCl_2$, a well-known mimetic agent of hypoxic/ischemic condition, resulted in neuronal cell death via caspase-3 dependent pathway. Extract of fermented C. sunki peel significantly rescued the $CoCl_2$-induced neuronal toxicity with the cell viability and appearance of apoptotic morphology. Cytoprotection with fermented C. sunki peel extract was associated with a decrease in activities of caspase-3 and cleavage of poly (ADP ribose) polymerase (PARP). In addition, increase in the intracellular ROS and release of cytochrome c from mitochondria to the cytosol were inhibited by treatment with extract of fermented C. sunki peel. Conclusion: Based on these data, fermented C. sunki peel extract might have a protective effect against $CoCl_2$-induced neuronal injury partly through generation of ROS and effectors involved in mitochondrial mediated apoptosis.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.21 no.2
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• pp.58-66
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• 2016

We have evaluated the ammonium data in seawater as a potential short-term index for marine environment through the following steps. 1. reviewing of chemical characteristics of ammonium in seawater, 2. comparative relationships of ammonium data with other water quality indices such as DO, COD, and nutrients from Typical Marine Environment(TME) and Special Marine Environment(SME). Ammonium data generally represent negative correlation with DO, while positive correlation with COD. In particular, under frequent cases of seawater conditions showing similar concentration of COD or DO, we have limited choice of explanation for such situation. However ODIN(ODIN/RDIN) or RDIN(RDIN/TDIN) ratio could provide advanced information to understand these seawater conditions. Based on these results, we suggest ammonium data as a potential short-period index for transilient marine environment, such as benthic flux of bottom sediment, hypoxia, and algal bloom. Under overcoming several handicaps, ammonium data could be an useful tool for better understand short transformation of marine environment.

• Environmental Engineering Research
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• v.25 no.3
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• pp.274-280
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• 2020

The marine sediment sustains from the anoxic condition due to increased nutrients of external sources. The nutrients are liberated from the sediment, which acts as an internal source. In hypoxic environments, anaerobic respiration results in the formation of several reduced matters, such as N₂ and NH₄⁺, N₂O, Fe²⁺, H₂S, etc. The experimental results have shown that nitrogen and sulfur played an influential, notable role in this biogeochemical cycle with expected chemical reductions and a 'diffusive' release of present nutrient components trapped in pore water inside sediment toward the bulk water. Nitate/ammonium, sulfate/sulfides, and ferrous/ferric irons are found to be the key players in these sediment-waters mutual interactions. Organonitrogen and nitrate in the sediment were likely to be converted to a form of ammonium. Reductive nitrogen is called dissimilatory nitrate reduction to ammonium and denitrification. The steady accumulation in the sediment and surplus increases in the overlying waters of ammonium strongly support this hypothesis as well as a diffusive action of the involved chemical species. Sulfate would serve as an essential electron acceptor so as to form acid volatile sulfides in present of Fe³⁺, which ended up as the Fe²⁺ positively with an aid of the residential microbial community.

• Molecular & Cellular Toxicology
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• v.1 no.1
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• pp.17-25
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• 2005

There are some critical drawbacks in the use of biomarkers for a global assessment of the toxicological impacts many chemicals and environmental pollutants have, primarily due to an individual biomarker's specificity for an explicit chemical or toxicant. In other words, the biomarker-based assessment methodology used to analyze toxicological effects lacks a high-throughput capability. Therefore, eco-toxicogenomics, or the study of toxicogenomics with organisms present within a given environmental locale, has recently been introduced with the advent of the so-called "-omics" era, which began with the creation of microarray technologies. Fish are comparable with humans in their toxicological responses and thus data from toxicogenomic studies performed with fish could be applied, with appropriate tools and implementation protocols, to the evaluation of environments where human or animal health is of concern. At present, there have been very active research streams for developing expression sequence tag (EST) databases (DBs) for zebra fish and rainbow trout. Even though few reports involve toxicogenomic studies with fish, a few groups have successfully fabricated and used cDNA microarrays or oligo DNA chips when studying the toxicological impacts of hypoxia or some toxicants with fish. Furthermore, it is strongly believed that this technology can also be implemented with non-model fish. With the standardization of DNA microarray technologies and ample progress in bioinformatics and proteomic technologies, data obtained from DNA microarray technologies offer not only multiple biomarker assays or an analysis of gene expression profiles, but also a means of elucidating gene networking, gene-gene relations, chemical-gene interactions, and chemical-chemical relationships. Accordingly, the ultimate target of eco-toxicogenomics should be to predict and map the pathways of stress propagation within an organism and to analyze stress networking.

• Journal of Korean Society on Water Environment
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• v.36 no.1
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• pp.1-13
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• 2020

The purpose of this study was to investigate the thermal and chemical stratification in Lake Paldang 2013-2018 weekly using Schmidt's stability index (SSI) and the index of chemical stratification (IC-i). The annual average for SSI was 19.1 g cm/㎠ with the maximum value of 45.3 g cm/㎠ in the summer and the minimum value of 4.8 g cm/㎠ in fall-winter showing seasonal differences as well as increased vertical mixing in the summer. The lake stability increased higher in 2016 as compared with the other period. The most influential factors of thermal stratification were temperature and heavy rainfall. Especially, high water temperature and a prolonged residence duration caused by reduced rainfall and inflows could result in an increase of the stratification period. While decreasing inflow and outflow at the end of the rainfall, the thermal stratification was restrengthened within 7-14 days, and then stabilized rapidly before the rainfall. IC-DO increased with high air temperature in the spring and fall-winter. However increasing sunshine duration and residence time and decreasing rate of outflow caused an increase of IC-DO in the summer. Rainfall (less than 800 mm/year) and discharge (less than 200 CMS) significantly declined in 2015 resulting in IC-DO (0.77) increased more than three times over the other years and bottom water hypoxia occurred. The SSI and IC-i used in this study could be applied to other lakes to understand changes in stratification and mixing dynamics.

• Journal of The Korean Society of Clinical Toxicology
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• v.1 no.1
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• pp.12-20
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• 2003

Cyanides and hydrogen sulfide ($H_2S$) are major chemical asphyxiants. They have common mechanism of action which inhibit cellular respiration and induce histotoxic hypoxia. They do not generate ATP, and all processes dependent on ATP are stopped. No extraction of $O_2$ from blood decreases AV $O_2$ differences, and the shift to anaerobic glycolysis brings about lactic acidosis with high anion gap. The mainstay of the treatment is rapid treatment with appropriate use of antidotes. However, there are several differences between cyanides and $H_2S$. First, $H_2S$ is not metabolized by enzymes such as thiosulfate. Thus thiosulfate does not play any role in treatment of $H_2S$. Second, $H_2S$ is a more potent inhibitor of cytochrome aa3 than cyanide. Third, $H_2S$ induces more divergent neurologic sequele than cyanide. Finally, $H_2S$ is not absorbed via skin.

• Korean Journal of Veterinary Research
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• v.39 no.1
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• pp.70-76
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• 1999

Magnesium ($Mg^{2+}$) plays an important role in the regulation of a range of intracellular processes. Regulation of extracellular $Mg^{2+}$ contents was studied in the anesthetized Sprague-Dawley (SD) rats. Animals were injected intraperitoneally with sodium nitrite ($NaNO_2$), and circulating $Mg^{2+}$($[Mg^{2+}]c$) was measured after the injection and then 10 and 20 minutes later. A dose-dependent increase in $[Mg^{2+}]c$ was observed in animals injected with $NaNO_2$ at a dose of 10mg/kg or higher. Pretreatment with methylene blue prevented the $NaNO_2$-induced increase in $[Mg^{2+}]c$. $[Mg^{2+}]c$ displayed an inverse linear correlation with hemoglobin and exponential correlation during $NaNO_2$ injection. Injection of KCN or rotenone also induced an increase in $[Mg^{2+}]c$. An increase in $[Mg^{2+}]c$ was observed when respiration rate was reduced from 100/min (140ml/min) to 10/min (14ml/min) during 30 min. These results indicate that changes in $[Mg^{2+}]c$ inversely reflect alteration of ATP in a model of metabolic inhibition.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.30 no.2
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• pp.55-60
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• 2022

A PSU (passenger service unit) is mounted on passenger seats in a cabin on an aircraft and consists of a crew call lamp, a reading lights, an information display lamp, an emergency oxygen generator, and an emergency oxygen mask. It is a safety device for providing convenience to passengers and providing oxygen to passengers in an emergency. This paper is a study on emergency oxygen supply systems and light systems of aircraft PSUs and a control device was developed to operate the system by analyzing the B767-300 aircraft's PSU circuit diagram. And the temperature generated by the B777-200ER aircraft's emergency oxygen generator was also measured by operating it directly. Through this, precautions for explaining the operation of an oxygen mask in an emergency were described and improvements were presented. Data acquired in these research processes can be used in the future to develop aircraft PSU (passenger service unit) and emergency oxygen generators.