• The Korean Journal of Physiology and Pharmacology
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• 제25권2호
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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.

• Asian-Australasian Journal of Animal Sciences
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• 제23권11호
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• pp.1462-1468
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• 2010

The effects of vitamin C and vitamin E with selenium on acid-base balance and some stress hormones were evaluated during heat stress in goats. Goats, 1.5 years of age, were divided into control, heat stress and antioxidant treatment groups 1, 2 and 3. Except for the control, all groups were exposed to a temperature of $40{\pm}2^{\circ}C$ with a relative humidity of 30% for 5 h/d for 21 days in a psychrometric chamber. Rectal temperature and respiratory rates were recorded daily post exposure. Blood samples were collected on every 3rd day for estimation of plasma vitamins C and E, total antioxidant activity and hormones, and separate blood samples were taken to estimate acid-base status. The rectal temperature and respiratory rates were increased (p<0.05) in the heat stress group only. Except for pH and $pO_2$, which were increased significantly (p<0.05) other parameters of acid-base balance such as $pCO_2$, $HCO_3^-$, $TCO_2$, BEb, BEcef, PCV and Hb were significantly decreased (p<0.05) in the heat stress group. An improvement in acid-base status was noted in the antioxidant supplemented groups. Prolactin and cortisol levels were significantly (p<0.05) higher and free T3 and T4 levels were significantly (p<0.05) lower in the heat stress group. Levels of prolactin and cortisol were decreased and free T3 and T4 were increased in antioxidant treatment groups. Different levels of antioxidant supplementation resulted in similar protection against heat stress.

• 한국표면공학회지
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• 제48권3호
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• pp.73-81
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• 2015

Chloride plating solution was fabricated by dissolving metal Ni powders in solution with HCl and deionized water. Effects of deposition conditions on the properties of Ni films electrodeposited from chloride baths were studied. Current efficiency of Ni films electrodeposited from the baths containing saccharin was decreased with increasing the current density. Residual stress of Ni thin films ware measured to be about 230 ~ 435 MPa in the range of current density of $10{\sim}25mA/cm^2$. Cathode current efficiency in baths without saccharin was initially increased with increasing pH, while it was decreased with increasing pH further. Cathode current efficiency in baths with saccharin (except at pH 2) exhibited less 10 ~ 20% than that in baths without saccharin. Residual stress of Ni films electrodeposited from baths without saccharin was measured to be 388 ~ 473 MPa in the range of pH 2 ~ pH 5 and then was increased to 551 MPa at pH 6. On the other hand, residual stress of Ni films electrodeposited from baths with saccharin was increased with increasing pH. Surface morphology was strongly affected by the change of current density, but slightly by solution pH and addition of saccharin.

• 한국미생물·생명공학회지
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• 제38권3호
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• pp.273-277
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• 2010

운데실프로지닌과 스트래토루빈 B는 S. coelicolor가 생산하는 붉은색 항생물질이다. 이번 연구에서 이들 붉은색 항생제의 생산성과 pH shock 스트레스와의 상관관계를 연구 하였다. 운데실프로디지닌과 스트랩토루빈 B의 생합성은 고체 R2YE 배지에서 산성 pH shock에 의해 증가되었다. 최적 pH shock은 pH 4로 비교군과 비교하여 각각 1.6배 및 2배 운데실프로디진과 스트랩토루빈 B의 생산성이 증가되었다. 게다가, 산성 pH 4의 세포 추출물은 T. mentagrophytes 에 대한 주목할만한 저항 활성을 나타내었다. 그러나, 중성 및 염기성 pH shock에서는 이들 항생제의 생산성뿐만 아니라 항진균 활성 증가가 일어나지 않았다. 그러므로, 비록 산성 pH shock이 간단하고 쉬운 방법이지만, 이들 붉은색 항생물질과 다른 이차대사산물의 생산성 향상에는 매우 효과적인 접근방법일 것이다.

• 환경생물
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• 제17권2호
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• pp.209-215
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• 1999

온도, pH및 염도 stress가 굴(Crassostrea gigas)의 malate dehydrogenase isozyme에 미치는 영향을 전기영동법으로 분석하였다. 대조군의 MDH isozyme은 2개의 band가 양극 쪽으로 이동되어 분리되었다. 각 실험 온도와 pH를 12시간 노출시킨 실험군에서는 1개의 band만 양극 쪽에서 분리되었고, 24시간과 48시간 노출한 실험군에서는 2개의 band가 모두 양극 쪽에서 분리되었다. 염분 농도가 5ppt 와 3ppt에서 12시간 노출시켰을 때 각각 2개의 band가, 10ppt와 40ppt에서는 각각 3개의 band가 분리되었고, 24시간과 48시간 노출 실험군에서는 2개의 band가 양극 쪽에서 분리되었다. 모든 isozyme pattern에서 각 band의 활성도는 실험 조건에 따라 각각의 특이성이 나타났다. 결과적으로 MDH isozyme의 변화는 굴이 환경 stress에 대한 생화학적 반응의 결과로 간주된다.

• Molecules and Cells
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• 제43권1호
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• pp.58-65
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• 2020

Fat mass and obesity-associated (FTO) gene helps to regulate energy homeostasis in mammals by controlling energy expenditure. In addition, FTO functions in the regulation of obesity and adipogenic differentiation; however, a role in osteogenic differentiation is unknown. This study investigated the effects of FTO on osteogenic differentiation of C3H10T1/2 cells and the underlying mechanism. Expression of osteogenic and endoplasmic reticulum (ER) stress markers were characterized by reverse-transcriptase polymerase chain reaction and western blotting. Alkaline phosphatase (ALP) staining was performed to assess ALP activity. BMP2 treatment increased mRNA expression of osteogenic genes and FTO. Overexpression of FTO increased expression of the osteogenic genes distal-less homeobox5 (Dlx5) and runt-related transcription factor 2 (Runx2). Activation of adenosine monophosphate-activated protein kinase (AMPK) increased FTO expression, and there was a positive feedback loop between FTO and p-AMPK. p-AMPK and FTO induced mild ER stress; however, tunicamycin-induced severe ER stress suppressed FTO expression and AMPK activation. In summary, FTO induces osteogenic differentiation of C3H10T1/2 cells upon BMP2 treatment by inducing mild ER stress via a positive feedback loop with p-AMPK. FTO expression and AMPK activation induce mild ER stress. By contrast, severe ER stress inhibits osteogenic differentiation by suppressing FTO expression and AMPK activation.

• 환경생물
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• 제18권4호
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• pp.377-385
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• 2000

인위적인 산성스트레스가 담수산 소백옆새우(Gammarus sobaegensis Ueno)에 미치는 영향을 정체성 수조건 하에서 급, 만성 생태독성실험을 통해 알아보았다. 급성독성 실험 시 pH 3 대역에서의 반수치사시간($LT_{50}$)은 평균 0.271($\pm$0.146)day로 개체의 크기 또는 먹이의 유무 그리고 주변 환경에 대한 적응능력에 관계없이 일정한 모습을 나타내고 있었다. pH4.0대역에서의 $LT_{50}$은 0.812($\pm$0.377) day로 연장되는 것이 확인되었다. 만성 독성실험의 경우 본 종의 반수치사시간은 pH 3.0일 때 약 6-7 day로 평균 6.313 ($\pm$0.828) day 인 것으로 나타났으며, pH 5.0일 때는 평균 9.475($\pm$4.881)day의 오랜 적응 기간을 갖는 것으로 확인되었다. 이러한 차이는 먹이의 공급유무에 따라 변동이 있다는 것을 알 수 있었고, 또한 주변 환경에 적응이 잘 된 개체일수록 오랜 기간동안 생존한다는 것을 알 수 있었다. 그리고 급, 만성 pH스트레스가 가해진 소백옆새우(G. sobaegensis)의 제 2아가미 표면조직에서 심한 주름현상을 확인할 수 있어, 결국 산성스트레스는 소백옆새우(G. sobaegensis)에 있어서 급성뿐만 아니라 만성적인 영향에서도 최종적으로는 매우 치명적으로 작용한다는 사실을 알 수 있었다.

• 지질공학
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• 제27권3호
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• pp.331-343
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• 2017

본 연구에서는 기존의 H-Pile+토류판 또는 H-Pile+토류판+차수그라우팅 공법의 안정성, 시공성 및 경제성을 개선하기 위해 H-Pile에 Plastic Sheet Pile(P.S.P)과 연성벽체인 P.S.P의 간격유지 및 보강기능을 위한 간격재(각형강관)를 결합한 토류벽체 System인 HCS공법을 개발하고, HCS공법을 구성하는 각 부재의 거동을 3차원 유한요소해석에 의해 규명하는 연구이다. HCS공법의 거동을 수치해석적으로 규명하기 위해 Plastic Sheet Pile 규격 3종류, H-Pile 규격 2종류 및 설치간격 3종류, 간격재 규격 1종류 및 설치간격 4종류에 대해 광범위한 3차원 유한요소해석을 실시하였다. 수치해석결과 $P.S.P-460{\times}131.5{\times}7t$ (PS7)와 H-Pile $250{\times}250{\times}9{\times}14$ (H250), $P.S.P473{\times}133.5{\times}9t$ (PS9)와 H-Pile $300{\times}200{\times}9{\times}14$ (H300)의 조합에서 상대적으로 유사한 응력비(=발생응력/허용응력)를 갖는 것으로 검토되어 이 제품의 조합이 경제적인 것으로 확인되었으며, P.S.P+H-Pile+간격재 복합체의 강성이 증가할수록 벽체의 수평변위와 상부지반의 연직변위가 감소하였다. 특히, H-Pile과 P.S.P의 강성차이로 인한 Arching 현상으로 P.S.P의 토압의 상당부분이 H-Pile로 응력(토압) 전이가 발생하여 P.S.P의 응력 및 변위는 미소하게 나타났다. 본 연구를 통하여 HCS공법을 구성하는 각각의 부재들의 거동을 확인할 수 있었으며, 확인된 연구결과를 통해 향후 HCS공법을 합리적이고 안정하며 경제적으로 적용하는 데 활용 가능하리라 판단된다.

• 한국표면공학회지
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• 제13권4호
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• pp.211-220
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• 1980

Internal stress of electrodeposited metals affect physical and mechanical characteristics of deposits. Internal stress of nickel deposits was reviewed intensively. Important outcomes are as follows. Substrate have an important effect on internal stress of electrodeposit. Origin of its internal stress could be explained mismatch of crystal lattice and coalescence of crystallites. When surface cleaning is not satisfying, instantaneous stress is low but the electrodeposited layer being thickened increasingly stress become to high and peeling phenomenon occurs. Effect of current density and temperature on internal stress is variable. Internal stress increases rapidly at pH 5 and above because of codepositing colloidal materials caused hydrolysis. Concentrations of nickel ion and $H_3BO_3$ ion affect little on internal stress and solution which contains impurities tend to increase stress. Especially impurities of $H_2O_2$ and iron ion have a great effect on internal stress. Additives are divided in two kind. One is increasing tensile stress another is increasing compressive stress. Concentrations of additives have a great effect on internal stress.

• The Korean Journal of Physiology and Pharmacology
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• 제25권4호
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• pp.297-305
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• 2021

Luteolin, a sort of flavonoid, has been reported to be involved in neuroprotective function via suppression of neuroinflammation. In this study, we investigated the protective effect of luteolin against oxidative stress-induced cellular senescence and its molecular mechanism using hydrogen peroxide (H₂O₂)-induced cellular senescence model in House Ear Institute-Organ of Corti 1 cells (HEI-OC1). Our results showed that luteolin attenuated senescent phenotypes including alterations of morphology, cell proliferation, senescence-associated 𝛽-galactosidase expression, DNA damage, as well as related molecules expression such as p53 and p21 in the oxidant challenged model. Interestingly, we found that luteolin induces expression of sirtuin 1 in dose- and time-dependent manners and it has protective role against H₂O₂-induced cellular senescence by upregulation of sirtuin 1 (SIRT1). In contrast, the inhibitory effect of luteolin on cellular senescence under oxidative stress was abolished by silencing of SIRT1. This study indicates that luteolin effectively protects against oxidative stress-induced cellular senescence through p53 and SIRT1. These results suggest that luteolin possesses therapeutic potentials against age-related hearing loss that are induced by oxidative stress.