• 한국환경과학회지
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• 제20권9호
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• pp.1069-1078
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• 2011

The environmental changes related to hypoxic water mass were investigated at Gamak bay in summer times, June, July and August 2006. The hypoxic water mass was found, in first, at the northern area of Gamak bay on 27 June. This water mass has been sustained until the end of August and disappear on 13 September. In Gamak bay, the hypoxic water mass was closely related to geography. During the formation of oxygen deficiency, changes in dissolved nutrients was studied and found that on surface layer and lower layer, DIN were 0.80 ${\mu}M$~19.8 ${\mu}M$(6.03 ${\mu}M$) and 1.13 ${\mu}M$～60.83 ${\mu}M$(10.66 ${\mu}M$), and DIP were 0.01 ${\mu}M$～0.92 ${\mu}M$(0.24 ${\mu}M$), and 0.01 ${\mu}M$～3.57 ${\mu}M$(0.49 ${\mu}M$), respectively, far higher distribution on lower layer of the water where hypoxic water mass was occurred. The configuration of phosphorus was analyzed to figure out the possibility of release of phosphorus from sediments. It was found that the Labile-Phosphorus, which is capable of easy move to water layer by following environmental change was found more than 70%. Therefore, in Gamak bay, it was found that the possibility of large amount of release of soluble P into the water, while hypoxic water mass was occurred in deep layer was higher. It is suggested that DIP in the northern sea of Gamak bay mainly sourced from the soluble P from lower layer of the waters where hypoxic water mass was created more than that from basin. However, existence form of phosphorus in sediments during normal times, not during creation of hypoxic water mass, needs further study.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2001년도 추계학술대회 및 정기총회
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• pp.114-114
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• 2001

Since hypoxia-inducible factor-lalpha (HIF-lalpha) and the arylhydrocarbon receptor (AhR) shared the AhR nuclear translocator (Arnt) for hypoxia- and AhR-mediated signaling, respectively, it was possible to establish the hypothesis that hypoxia could regulate Cyplal expression. In order to understand the mechanism of Cyplal gene expression, we demonstrated here that hypoxic agents such as cobalt chloride, desferrioxarnine, and picolinic acid reduced the TCDD induced Cyplal promoter activity based on the determination of luciferase activity in Hepa I cells transfected with pmCypla1-Luc. Also cobalt chloride inhibited the TCDD stimulated Cyplal mRNA level as well as EROD activities in both Hepa I and MCF-7 cells. Hypoxic agents such as cobalt chloride, picolinic acid, and desferrioxamine showed inhibition of luciferase activity that was induced by lnM TCDD treatment with dose dependent manner. Concomitant treatment of 150${\mu}$M ferrous sulfate with 1∼100${\mu}$M desferrioxarnine or 1∼100${\mu}$M picolinic acid recovered from the hypoxic agents-inhibited luciferase activity that was stimulated by TCDD. Reciprocally, the hypoxic agents down regulated TCDD induced Cyplal mRNA level and CYP1A1 enzyme activity in Hepa I cells.

• 운동영양학회지
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• 제13권1호
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• pp.45-50
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• 2009

This study evaluated the effects of D-ribose supplementation on exercise time in a hypoxic chamber. Eight healthy young males participated in experiments under all four different conditions; placebo+normoxic, placebo+hypoxic, ribose+normoxic, and ribose+hypoxic. Subjects took 1 g per 10 kg body weight of ribose dissolved in drinking water 30 minutes before and immediately before running. We observed the run-to-exhaustion time, the maximum heart rate, and the changing pattern of the heart rate during exercise. The longest running time was achieved when subjects ran under normoxic condition with ribose supplementation. The shortest running time occurred when subjects ran under hypoxic conditions without ribose supplementation. We measured MDA and GPx to determine any changes in oxidative stresses or antioxidative systems. MDA was affected by the environmental conditions and the running time. The activity of GPx showed a significant difference only with the different environmental conditions of exercise. The results of this study indicate that ribose can be considered a possible ergogenic during exercise in specific conditions, but more detailed and well-controlled studies are needed to make a definitive conclusion.

• BMB Reports
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• 제40권6호
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• pp.895-898
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• 2007

The oxygen dependent regulation of DNA replication is an essential property of proliferating mammalian cells. In human T24 bladder cancer cells, several hours of hypoxia leads to reversible DNA replication arrest and re-entry of oxygen induces a burst of replication initiation. This short communication provides strong evidence that PD184352 initiates DNA replication in living hypoxic cells without elevating the oxygen level. PD184352 releases the regular hypoxic replicon arrest, however, at a low intensity compared to the effect of reoxygenation. Moreover, PD184352 shows no effect on normoxically incubated as well as reoxygenated T24 cells.

• 대한의생명과학회지
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• 제17권3호
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• pp.185-190
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• 2011

Adenovirus type 5 (Ad5) vectors have been used for gene transfer to a wide variety of cell types in vivo and in vitro. The advantages of adenovirus vectors include the high titer of virus readily obtained in large scale preparations, their ability to transduce dividing and non dividing cells, and the high level of transgene expression. Since adenovirus vectors do not integrate in host cell DNA, there is a lack of insertional mutagenesis. However, many human tumor cells lack expression of the adenovirus 5 receptors and contain areas of hypoxia. In order to identify the pattern of replication and gene expression of oncolytic adenovirus in hypoxic condition, multiple different fiber modified Ads (Ad5F/S11, Ad5F/S35, Ad5F/K7, Ad5F/K21, and Ad5F/RGD) was compared. The replication of all fiber modified adenovirus was inhibited in hypoxic condition in HEK 293 cells, but gene expression has variety on different tumor cell lines and the level of coxackievirus and adenovirus receptor (CAR) expression. These data suggest that CAR expression pattern and hypoxic condition of tumor are considered for optimal oncolytic adenovirus application.

• Journal of the korean society of oceanography
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• 제34권4호
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• pp.236-240
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• 1999

A preliminary study was carried out to find characteristics of microbial trophic relations in hypoxic waters of Lake Shihwa in May and August 1996. Abundances of bacteria, viruses, and heterotrophic nanoflagellates (HNF) and HNF grazing on bacteria were measured. Dissolved O$_2$ (DO) saturation ranged from 13 to 34% in the bottom waters, and % of DO saturation strongly correlated with salinity. Ratios of HNF-to-bacteria abundance (42-118${\times}$10$^{-5}$) and biomass (0.06-0.25), and ratios of virus-to-bacteria abundance (110-297) in the hypoxic water were similar to those found in the surface layer, indicating similar structures of microbial abundances and trophic functions in hypoxicand surface waters during the study period. In the hypoxic water, an energy flow from organic matter to bacteria to HNF might operate as equally as in oxic surface layer.

• Radiation Oncology Journal
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• 제34권3호
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• pp.230-238
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• 2016

Purpose: Hypoxia can impair the therapeutic efficacy of radiotherapy (RT). Therefore, a new strategy is necessary for enhancing the response to RT. In this study, we investigated whether the combination of nanoparticles and RT is effective in eliminating the radioresistance of hypoxic tumors. Materials and Methods: Gold nanoparticles (GNPs) consisting of a silica core with a gold shell were used. CT26 colon cancer mouse model was developed to study whether the combination of RT and GNPs reduced hypoxia-induced radioresistance. Hypoxia inducible $factor-1{\alpha}$ ($HIF-1{\alpha}$) was used as a hypoxia marker. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining were conducted to evaluate cell death. Results: Hypoxic tumor cells had an impaired response to RT. GNPs combined with RT enhanced anti-tumor effect in hypoxic tumor compared with RT alone. The combination of GNPs and RT decreased tumor cell viability compare to RT alone in vitro. Under hypoxia, tumors treated with GNPs + RT showed a higher response than that shown by tumors treated with RT alone. When a reactive oxygen species (ROS) scavenger was added, the enhanced antitumor effect of GNPs + RT was diminished. Conclusion: In the present study, hypoxic tumors treated with GNPs + RT showed favorable responses, which might be attributable to the ROS production induced by GNPs + RT. Taken together, GNPs combined with RT seems to be potential modality for enhancing the response to RT in hypoxic tumors.

• Annals of Clinical Neurophysiology
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• 제15권2호
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• pp.42-47
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• 2013

Background: Diffusion-weighted image (DWI) might be useful to predict the prognosis of acute hypoxic encephalopathy. The aim of our study was to test whether the early change and extent of DWI abnormalities can be an indicator of the clinical outcome of hypoxic encephalopathy. Methods: Forty-four patients who were diagnosed as hypoxic encephalopathy due to the cardiorespiratory arrest were retrospectively identified. Clinical variables were determined, and the DWI abnormalities were counted by four areas: cortex, subcortical white matter, cerebellum and deep grey matter, and were divided into three groups by the extent of lesions. Prognosis was classified as 'poor' (Glasgow coma scale (GSC) at 30 days after arrest <9 or death) and 'good' (GSC at 30 days after arrest ${\geq}9$). Results: GCS at day 3 (p<0.001), presence of seizure (p=0.01), and presence of lesion (p<0.001) were significantly different in prognosis, but statistically there is no association with the extent of lesions and prognosis (p=0.26). Conclusions: Presence of early DWI changes could predict the clinical outcome of hypoxic encephalopathy after cardiorespiratory arrest.

• 한국해양환경ㆍ에너지학회지
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• 제13권1호
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• pp.30-42
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• 2010

빈산소 수체 거동에 미치는 내부파의 영향을 유체정역학-생태계 결합 모델을 기반으로 하는 수치해석을 이용하여 일본 비와호에 적용하여 고찰하였다. 수치모델은 유체정역학 부 모델과 생태계 부 모델로 이루어져 있고, 3년간의 예비 수치모사를 수행한 후 2007년 4월에서 2008년 3월까지의 기간에 대해 본 수치해석이 이루어졌다. 수치해석의 결과는 계측된 수질의 수직적 구조를 재현하였고, 2007년 9월 30일에서 10월 21일까지의 기간에 나타난 주된 내부파는 켈빈파와 포앙카레파로서 그 주기는 각각 1.63 또는 1.77일이고 0.48일 이었다. 10월 중에 나타난 저층의 빈산소 수체는 상층에 수온약층이 형성된 기간 동안 유지되었다. 늦가을에서 겨울 동안은 수체의 상부와 하부간의 밀도차이가 줄어들고 내부파의 진폭은 증가된다. 빈산소 수체가 내부파의 영향으로 이동을 시작하게 되고, 이 빈산소 수체의 이동으로 깊은 수심의 수생생물 서식지가 감소하게 된다.

• 대한치과마취과학회지
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• 제14권2호
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• pp.107-114
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• 2014

Background: Angiogenesis has been recognized an essential precondition for osteogenesis. Because reduction and disruption of the blood supply to tissue cause tissue hypoxia, pathological bone loss affected by hypoxia often can occur in various clinical conditions. The effects of propofol on the process of osteogenesis have received little direct attention. Therefore, we investigated the effect of propofol on the growth and function of osteoblasts under hypoxic condition. Methods: After propofol (3, 30, $300{\mu}M$) preconditioning for 2 hours, hFOB 1.19 human osteoblast cells were cultured under 1 % oxygen tension for 48 hours. Using real time PCR and western blot analysis, we analyzed the expression of, BMP-2, TGF-${\beta}1$, type I collagen, osteocalcin, HIF-1s and Akt. Cell viability was also determined by MTT assay. Results: Propofol preconditioning on hypoxic-cultured osteoblast promoted the expressions of BMP-2, TGF-${\beta}1$, type I collagen and osteocalcin and induced hypoxia-mediated HIF-1 activation and the expression of Akt protein. Propofol with $300{\mu}M$ significant decreased cell viability compared to control. Conclusions: Clinically relevant concentrations of propofol are not cytotoxic to hypoxic osteoblasts in vitro. Propofol preconditioning on hypoxic-cultured osteoblast stimulates proliferation and differentiation of osteoblast through induced expression of BMP-2, TGF-${\beta}1$, type I collagen and osteocalcin. Propofol might promote angiogenesis and bone regeneration under hypoxic condition.