• The Korean Journal of Physiology and Pharmacology
• /
• v.16 no.2
• /
• pp.139-144
• /
• 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.

• Journal of Integrative Natural Science
• /
• v.6 no.3
• /
• pp.125-137
• /
• 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
• /
• v.4 no.1
• /
• pp.79-83
• /
• 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
• /
• v.4 no.4
• /
• pp.383-389
• /
• 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.

• Journal of the Society of Disaster Information
• /
• v.11 no.4
• /
• pp.581-588
• /
• 2015

This study was conducted by utilizing simulation (FDS6) the fire characteristics of the flammable substances such as cable compartment of a small space in the EPS room type. In the partitioned space of a room EPS supply of oxygen does not facilitate the combustion of the upward-sloping curve, as in a standard fire curve is not observed. Simulation results in a situation where ventilation is limited to the heat release rate and smoke emission characteristics of the fire showed a complex and unstable form a repeating rise and fall. Fire time was longer than the fire load. Change in the smoke emission than the heat release rate is slow, but changes of the overall surface was found to exhibit affinity.

• Korean Journal of Soil Science and Fertilizer
• /
• v.39 no.5
• /
• pp.292-297
• /
• 2006

A research was carried out to investigate the release pattern of slow release nitrogen fertilizer compound(SRNC) that is latex coated urea(LCU) and to recommend the application rate of the fertilizer at dry seeding rice culture in Honam plain area. The experiment was conducted at experimental field(Jeonbug series, fine silty, mixed, nonacid, mesic family of Fluvaquentic Endoaquepts) of National Honam Agricultural Research Institute. A medium late maturing rice variety (Dongjinbyeo) was seeded at the rate of $60kg\;ha^{-1}$ by drill seeder on April 1, 1997 and March 30, 1998. Fertilizer application rate was $160-90-110kg\;ha^{-1}$ for $N-P_2O_5-K_2O$. Soil ammonium nitrate($NH_4-N$) contents remained higher in all SRNC plots than conventional ones and higher with the increase of SRNC application rate until panicle formation stage, but the contents was higher in the conventional than NRNC plots at the heading stage. The plant hight was taller in SRNC than conventional plots until maximum tiller stage, but became similar in both conventional and SRNC plots at heading stage. The culm and panicle number was greater in SRNC than conventional plots throughout all growth stage, but the effective tiller rate was higher in conventional ones. Nitrogen efficiency was higher in the SRNC than conventional plots, but the efficiency was decreasing with the higher SRNC level. The spikelet number per unit area was greater in SRNC than conventional plots, and increased with higher SRNC level. The more spikelet number with higher NRNC level resulted in lower 1,000-grain weight. The rice yield in conventional plot was similar with only 60% SRNC level, but lower than 80% and 100% SRNC levels. However, slight lodging was observed in 100% SRNC level. In conclusions, we recommend NRNC application level as 80% of standard nitrogen application for early dry seeding culture of rice Honam plain area.

• Asian-Australasian Journal of Animal Sciences
• /
• v.27 no.11
• /
• pp.1577-1583
• /
• 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.

• Applied Chemistry for Engineering
• /
• v.8 no.5
• /
• pp.715-721
• /
• 1997

W/O/W multiple emulsions were prepared comprising $MgSO_4$ in the inner aqueous phase as a model drug. The stability and drug release behavior of the multiple emulsions were studied using optical microscopy, viscometry and conductometry. Glucose was introduced in the outer aqueous phase to reduce the osmotic pressure gradient across the oil layer arising from the localization of drug molecules in the inner water phase. It was found that the presence of glucose was effective in stabilization of the multiple emulsions and in control of the release rate of drug more evidently when oil phase was partially hydrophilized with cetostearyl alcohol. This may be attributed to the fact that the migration of water accompanying the hydrophilic surfactant to the inner water phase was limited under a reduced osmotic pressure gradient and thereby slow down the destabilization of the oil/inner water interface.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.5
• /
• pp.2335-2340
• /
• 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
• /
• v.14 no.5
• /
• pp.573-578
• /
• 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.