• The Korean Journal of Physiology and Pharmacology
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• 제16권2호
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• pp.139-144
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• 2012

It has been reported that activation of metabotropic glutamate receptor 1 (mGluR1) can mediate endocannabinoid-induced short-term depression of synaptic transmission in cerebellar parallel fiber (PF)-Purkinje cell (PC) synapse. mGluR1 has signaling pathways involved in intracellular calcium increase which may contribute to endocannabinoid release. Two major mGluR1-evoked calcium signaling pathways are known: (1) slow-kinetic inward current carried by transient receptor potential canonical (TRPC) channel which is permeable to $Ca^{2+}$; (2) $IP_3$-induced calcium release from intracellular calcium store. However, it is unclear how much each calcium source contributes to endocannabinoid signaling. Here, we investigated whether calcium influx through mGluR1-evoked TRPC channel contributes to endocannabinoid signaling in cerebellar Purkinje cells. At first, we applied SKF96365 to inhibit TRPC, which blocked endocannabinoid-induced short-term depression completely. However, an alternative TRP channel inhibitor, BTP2 did not affect endocannabinoid-induced short-term depression although it blocked mGluR1-evoked TRPC currents. Endocannabinoid signaling occurred normally even though the TRPC current was mostly blocked by BTP2. Our data imply that TRPC current does not play an important role in endocannabinoid signaling. We also suggest precaution in applying SKF96365 to inhibit TRP channels and propose BTP2 as an alternative TRPC inhibitor.

• 통합자연과학논문집
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• 제6권3호
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• pp.125-137
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• 2013

Promising evidence suggests that amyloid beta peptide ($A{\beta}$), a key mediator in age-dependent neuronal and cerebrovascular degeneration, activates death signalling processes leading to neuronal as well as non-neuronal cell death in the central nervous system. A major cellular event in $A{\beta}$-induced apoptosis of non-neuronal cells, including cerebral endothelial cells, astrocytes and oligodendrocytes, is mitochondrial dysfunction. The apoptosis signalling cascade upstream of mitochondria entails $A{\beta}$ activation of neutral sphingomyelinase, resulting in the release of ceramide from membrane sphingomyelin. Ceramide then activates protein phosphatase 2A (PP2A), a member in the ceramide-activated protein phosphatase (CAPP) family. PP2A dephosphorylation of Akt and FKHRL1 plays a pivotal role in $A{\beta}$-induced Bad translocation to mitochondria and transactivation of Bim. Bad and Bim are pro-apoptotic proteins that cause mitochondrial dysfunction characterized by excessive ROS formation, mitochondrial DNA (mtDNA) damage, and release of mitochondrial apoptotic proteins including cytochrome c, apoptosis inducing factor (AIF), endonuclease G and Smac. The cellular events activated by $A{\beta}$ to induce death of non-neuronal cells are complex. Understanding these apoptosis signalling processes will aid in the development of more effective strategies to slow down age-dependent cerebrovascular degeneration caused by progressive cerebrovascular $A{\beta}$ deposition.

• Asian-Australasian Journal of Animal Sciences
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• 제4권1호
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• pp.79-83
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• 1991

Diurnal variation in faecal chromic oxide levels was estimated from 4 hourly faecal sampling of 56 wethers allotted to one of six different feeding patterns. Sampling occurred on days 6 and 7 (Period 1) after a controlled release device was administered, and was repeated on days 14 and 15 (Period 2) following re-randomisation of the wethers to the feeding patterns. Increasing the frequency of feeding tended to be associated with higher faecal chromic oxide levels (p < 0.05), particularly in wethers fed thrice daily at 8 hour intervals. There was no interaction between feeding pattern and period, sampling day or time within-day. There were significant period x time within-day (p < 0.05) and day x time within-day (p < 0.001) interactions, indicating that variation in faecal chromic oxide between sample times was not consistent. This implies that sampling at any time of day is unlikely to result in a biased estimate of pasture intake, providing sufficient samples are collected. Significant period (p < 0.001) and period x day (p < 0.01) effects were associated with slow faecal chromic oxide equilibration in period 1. Equilibration did not occur until after day 7, indicating a need for caution when commencing sampling.

• Weed & Turfgrass Science
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• 제4권4호
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• pp.383-389
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• 2015

The use of zoysiagrass (Zoysia japonica Steud.) in the transition zone is limited because of a lack of cold hardiness although zoysiagrass has many advantages compared to other warm-season and cool-season grasses. Late-fall N fertilization is often applied for darker green color of turfgrass in early spring and more extensive root growth without rapid top growth. The objective of the study was to evaluate the effects of late fall N application and turf cover for zoysiagrass spring green-up. Clear polyvinyl chloride (PVC) film was used for turf cover. The amount of N applied were 5 and $10g\;N\;m^{-2}$ for the low and high N rate treatments, respectively. Covered zoysiagrass had greater turfgrass color and quality in early spring than non-covered zoysiagrass. The high N rate had 0.6 to 2.3 greater turfgrass quality than the low N rate on 7 of 9 rating dates. Slow-release N as late fall fertilization is more effective for turfgrass color and quality than fast-release N in spring. Turf cover could reduce the period of yellow zoysiagrass, and the earlier time of spring green-up could be advanced by increasing turfgrass quality and growth of zoysiagrass.

• 한국재난정보학회 논문집
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• 제11권4호
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• pp.581-588
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• 2015

본 연구는 구획된 소공간유형의 EPS실에서 케이블 등의 가연성물질에 대한 화재특성을 시뮬레이션(FDS6)을 활용하여 진행하였다. 구획된 공간인 EPS실에서는 산소의 공급이 원활하지 않아 표준화재곡선에서와 같은 우상향의 연소곡선이 나타나지 않았다. 환기가 제한되는 상황에서 열방출율과 연기 방출량에 대한 시뮬레이션 결과는 상승과 하락을 반복하며 불안정한 형태의 복잡한 화재특성을 보였다. 화재시간은 화재하중에 비하여 길게 나타났다. 열방출율에 비하여 연기 방출량의 변화는 느리게 진행되었으나 전체적인 면에서 변화양상은 유사성을 보이는 것으로 확인되었다.

• 한국토양비료학회지
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• 제39권5호
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• pp.292-297
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• 2006

호남평야지에서 건답직파 조기파종재배에 알맞은 완효성복합비료 시용량을 구명하고자 '97~'98년에 호남농업시험장 수도포장인 전북통(미사질양토)에서 동진벼를 공시하여 시험한 결과를 요약하면 다음과 같다. 토양의 암모니아태 질소는 유수형성기까지는 관행시비보다 모든 완효성비료 시비에서 많았고 완효성비료 시용량이 많을수록 많았으나 출수기에는 이삭거름시용으로 관행시비가 완효성비료보다 많았다. 초장은 최고 분얼기까지는 관행시비보다 완효성비료시비에서 길었으나 간장은 완효성비료 100%시용을 제외하고는 관행시비와 같거나 짧았다. 경수와 수수는 모든 생육시기에서 관행시비보다 완효성비료시용에서 많았고 완효성비료 시용량이 많을수록 많았으나 유효경비율은 정수 및 수수와 반대의 경향이었다. 질소 이용율은 관행시비보다 완효성비료시용에서 높았고 완효성비료 시용량이 많을수록 감소되는 경향이었다. 단위면적당 입수는 관행시비보다 완효성비료를 증시할수록 많았으나 현미 천립중은 단위면적당 입수와 반대의 경향이었다. 쌀 수량은 완효성비료 60% 시비는 관행시비와 차이가 없었으나 완효성비료 80%이상에서는 관행시비보다 증수되었다. 이상에서와 같이 질소이용율, 생육, 도복 및 수량을 고려한 벼 건답직파 조기파종 재배에 알맞은 완효성비료 전층시비량은 질소관행 시비량의 80%정도라고 판단된다.

• Asian-Australasian Journal of Animal Sciences
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• 제27권11호
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• pp.1577-1583
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• 2014

Encapsulation is a method used to protect material from certain undesirable environments, for controlled release at a more favorable time and place. Animal productivity would be enhanced if feed additives are delivered to be utilized at their site of action, bypassing the rumen where they are likely to be degraded by microbial action. A novel method of encapsulation with sesame gum was used to coat nitrate, a known enteric methane mitigating agent, and tested for the effect on methane reduction and other in vitro fermentation parameters using rumen fluid from cannulated Hanwoo steers. Orchard grass was used as basal diet for fermentation. The treatments were matrix (1.1 g sesame gum+0.4 g sesame oil cake) only, encapsulated nitrate (matrix+nitrate [21 mM]), free nitrate (21 mM), and a control that contained no additive. Analyses of fermentation parameters were done at 0, 3, 6, 9, 12, 24, and 48 h time periods. In comparison to control, both free and encapsulated nitrate produced significantly reduced (p<0.01) methane (76% less) and also the total volatile fatty acids were reduced. A significantly higher (p<0.01) concentration of ammonia nitrogen was obtained with the encapsulated nitrate treatment (44%) compared to the free form (28%) and matrix only (20%) (p = 0.014). This might suggest slow release of encapsulated nitrate so that it is fully reduced to ammonia. Thus, this pioneering study found a significant reduction in methane production following the use of sesame gum encapsulated nitrate that shows the potential of a controlled release system in enhancing sustainability of ruminant production while reducing/eliminating the risk of nitrite toxicity.

• 공업화학
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• 제8권5호
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• pp.715-721
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• 1997

$W_1/O/W_2$ 다중유화의 내부수상($W_1$)에 전해질인 $MgSO_4$를 모델약물로 주입하여 안정성과 약물방출 거동을 현미경관찰, 점도 및 전도도의 변화를 통해 관찰하였다. 내상에 약물을 도입함으로써 내부와 외부수상간의 삼투압차를 유발하여 다중유화계의 불안정성을 초래하였으며 이를 완화하기 위하여 외부수상($W_2$)에 글루코즈를 첨가하여 효과를 살펴본 결과 글루코즈의 유효삼투압 당량이 내부에 포함된 약물의 삼투압 당량과 유사해짐에 따라 안정성이 향상되었을 뿐아니라 초기 약물방출 속도도 글루코즈 농도에 의해 조절할 수 있음을 발견하였다. 이는 삼투압차에 의한 수분 이동시 친수성 계면활성제를 동반하여 내부수상/오일상 계면을 파괴하는 것을 방지하기 때문으로 보인다. 또한 이와같은 현상은 오일상이 cetostearyl alcohol에 의하여 친수화되었을 때 뚜렷하게 나타났다.

• Asian Pacific Journal of Cancer Prevention
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• 제15권5호
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• pp.2335-2340
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• 2014

Paclitaxel is hydrophobic in nature and is recognized as a highly toxic anticancer drug, showing adverse effects in normal body sites. In this study, we developed a polymeric nano drug carrier for safe delivery of the paclitaxel to the cancer that releases the drug in a sustained manner and reduces side effects. N-isopropylacrylamide/vinyl pyrrolidone (NIPAAm/VP) nanoparticles were synthesized by radical polymerization. Physicochemical characterization of the polymeric nanoparticles was conducted using dynamic light scattering, transmission electron microscopy, scanning electron microscopy and nuclear magnetic resonance, which confirmedpolymerization of formulated nanoparticles. Drug release was assessed using a spectrophotometer and cell viability assays were carried out on the MCF-7 breast cancer and B16F0 skin cancer cell lines. NIPAAm/VP nanoparticles demonstrated a size distribution in the 65-108 nm range and surface charge measured -15.4 mV. SEM showed the nanoparticles to be spherical in shape with a slow drug release of ~70% in PBS at $38^{\circ}C$ over 96 h. Drug loaded nanoparticles were associated with increased viability of MCF-7 and B16F0 cells in comparison to free paclitaxel. Nano loaded paclitaxel shows high therapeutic efficiency by sustained release action for the longer period of time, i increasing its efficacy and biocompatibility for human cancer therapy. Therefore, paclitaxel loaded (NIPAAm/VP) nanoparticles may provide opportunities to expand delivery of the drug for clinical selection.

• Macromolecular Research
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• 제14권5호
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• pp.573-578
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• 2006

Three different, polymer-platinum conjugates (hydrogels, microparticles, and nanoparticles) were synthesized by complexation of cis-dichlorodiammineplatinum(II) (cisplatin) with partially succinylated glycol chitbsan (PSGC). Succinic anhydride was used as a linker to introduce cisplatin to glycol chitosan (GC). Succinylation of GC was investigated systematically as a function of the molar ratio of succinic anhydride to glucosamine, the methanol content in the reaction media, and the reaction temperature. By controlling the reaction conditions, water-soluble, partially water-soluble, and hydrogel-forming PSGCs were synthesized, and then conjugated with cisplatin. The complexation of cisplatin with water-soluble PSGC via a ligand exchange reaction of platinum from chloride to the carboxylates induced the formation of nano-sized aggregates in aqueous media. The hydrodynamic diameters of PSGC/cisplatin complex nano-aggregates, as determined by light scattering, were 180-300 nm and the critical aggregation concentrations (CACs), as determined by a fluorescence technique using pyrene as a probe, were $20-30{\mu}g/mL$. The conjugation of cisplatin with partially water-soluble PSGC, i.e., borderline between water-soluble and water-insoluble PSGC, produced micro-sized particles $<500{\mu}m$. Cisplatin-complexed PSGC hydrogels were prepared from water-insoluble PSGCs. All of the cisplatin-incorporated, polymer matrices released platinum in a sustained manner without any significant initial burst, suggesting that they may all be useful as slow release systems for cisplatin. The release rate of platinum increased with the morphology changes from hydrogel through microparticle to nanoparticle systems.