Russian Nonproliferation Policy and the Korean Peninsula

Efforts to resolve the threat posed to Northeast Asia\u27s security by North Korea\u27s nuclear proliferation through six-party negotiations are proceeding with great difficulty. As in any multilateral process, a major problem is understanding the goals and perspectives of each of the participants. This monograph focuses upon Moscow’s perspectives with regard to North Korea’s nuclear program and Russia’s own standing in Northeast Asia, as well as of the other participants in those negotiations, since their views unfortunately are not well-known or readily available in the United States.https://press.armywarcollege.edu/monographs/1701/thumbnail.jp

The Impact of the Ukraine War on Russian-North Korean Relations

This article examines the impact of the Ukraine war on Russian-North Korean relations at three different levels. At the international level, the war will bring two power groups into confrontation. The closer security cooperation between Russia and China will form an illiberal group that will set the security environment for North Korea to establish a new international identity. At the regional level, Russian-Chinese security alignment will be reinforced, which North Korea will exploit. At the bilateral level, Russian-North Korean relations will be strengthened as Russia's influence in Northeast Asia wanes.Y

The Development of Russian Far East and Eastern Siberia and the Future of Northeast Asia

The purpose of this short paper is to introduce a new concept and way of thinking about the future of Northeast Asia in conjunction with the development of Russian Far East and Eastern Siberia. The basic arguments of this paper are: first, the specialists should shed the conventional definition of geographical boundaries, especially in defining Northeast Asia; second, Russia’s Far Eastern development can make a significant contribution to the regional community building depending on how creatively and imaginatively the development proceeds; lastly, it is high time to start preparation for the future of Northeast Asia before it gets too late. In this regard, at the end of this paper the authors introduce their initial effort to establish a consortium, the purpose of which is to lay groundwork for the establishment of an institute for Northeast Asian community buildin

Differential Effects of Histidine and Histidinamide versus Cysteine and Cysteinamide on Copper Ion-Induced Oxidative Stress and Cytotoxicity in HaCaT Keratinocytes

Metal chelators are used for various industrial and medical purposes based on their physicochemical properties and biological activities. In biological systems, copper ions bind to certain enzymes as cofactors to confer catalytic activity or bind to specific proteins for safe storage and transport. However, unbound free copper ions can catalyze the production of reactive oxygen species (ROS), causing oxidative stress and cell death. The present study aims to identify amino acids with copper chelation activities that might mitigate oxidative stress and toxicity in skin cells exposed to copper ions. A total of 20 free amino acids and 20 amidated amino acids were compared for their copper chelation activities in vitro and the cytoprotective effects in cultured HaCaT keratinocytes exposed to CuSO4. Among the free amino acids, cysteine showed the highest copper chelation activity, followed by histidine and glutamic acid. Among the amidated amino acids, cysteinamide showed the highest copper chelation activity, followed by histidinamide and aspartic acid. CuSO4 (0.4–1.0 mM) caused cell death in a concentration-dependent manner. Among the free and amidated amino acids (1.0 mM), only histidine and histidinamide prevented the HaCaT cell death induced by CuSO4 (1.0 mM). Cysteine and cysteinamide had no cytoprotective effects despite their potent copper-chelating activities. EDTA and GHK-Cu, which were used as reference compounds, had no cytoprotective effects either. Histidine and histidinamide suppressed the CuSO4-induced ROS production, glutathione oxidation, lipid peroxidation, and protein carbonylation in HaCaT cells, whereas cysteine and cysteinamide had no such effects. Bovine serum albumin (BSA) showed copper-chelating activity at 0.5–1.0 mM (34–68 mg mL−1). Histidine, histidinamide, and BSA at 0.5–1.0 mM enhanced the viability of cells exposed to CuCl2 or CuSO4 (0.5 mM or 1.0 mM) whereas cysteine and cysteinamide had no such effects. The results of this study suggest that histidine and histidinamide have more advantageous properties than cysteine and cysteinamide in terms of alleviating copper ion-induced toxic effects in the skin

Antioxidant Effects of Korean Propolis in HaCaT Keratinocytes Exposed to Particulate Matter 10

Air pollution causes oxidative stress that leads to inflammatory diseases and premature aging of the skin. The purpose of this study was to examine the antioxidant effect of Korean propolis on oxidative stress in human epidermal HaCaT keratinocytes exposed to particulate matter with a diameter of less than 10 μm (PM10). The total ethanol extract of propolis was solvent-fractionated with water and methylene chloride to divide into a hydrophilic fraction and a lipophilic fraction. The lipophilic fraction of propolis was slightly more cytotoxic, and the hydrophilic fraction was much less cytotoxic than the total extract. The hydrophilic fraction did not affect the viability of cells exposed to PM10, but the total propolis extract and the lipophilic fraction aggravated the toxicity of PM10. The total extract and hydrophilic fraction inhibited PM10-induced ROS production and lipid peroxidation in a concentration-dependent manner, whereas the lipophilic fraction did not show such effects. High-performance liquid chromatography with photodiode array detection (HPLC-DAD) analysis showed that the hydrophilic fraction contained phenylpropanoids, such as caffeic acid, p-coumaric acid, and ferulic acid, whereas the lipophilic faction contained caffeic acid phenethyl ester (CAPE). The former three compounds inhibited PM10-induced ROS production, lipid peroxidation, and/or glutathione oxidation, and ferulic acid was the most effective among them, but CAPE exhibited cytotoxicity and aggravated the toxicity of PM10. This study suggests that Korean propolis, when properly purified, has the potential to be used as a cosmetic material that helps to alleviate the skin toxicity of air pollutants

Identification of L-Cysteinamide as a Potent Inhibitor of Tyrosinase-Mediated Dopachrome Formation and Eumelanin Synthesis

The purpose of this study is to identify amino acid derivatives with potent anti-eumelanogenic activity. First, we compared the effects of twenty different amidated amino acids on tyrosinase (TYR)-mediated dopachrome formation in vitro and melanin content in dark-pigmented human melanoma MNT-1 cells. The results showed that only L-cysteinamide inhibited TYR-mediated dopachrome formation in vitro and reduced the melanin content of cells. Next, the antimelanogenic effect of L-cysteinamide was compared to those of other thiol compounds (L-cysteine, N-acetyl L-cysteine, glutathione, L-cysteine ethyl ester, N-acetyl L-cysteinamide, and cysteamine) and positive controls with known antimelanogenic effects (kojic acid and β-arbutin). The results showed the unique properties of L-cysteinamide, which effectively reduces melanin content without causing cytotoxicity. L-Cysteinamide did not affect the mRNA and protein levels of TYR, tyrosinase-related protein 1, and dopachrome tautomerase in MNT-1 cells. L-Cysteinamide exhibited similar properties in normal human epidermal melanocytes (HEMs). Experiments using mushroom TYR suggest that L-cysteinamide at certain concentrations can inhibit eumelanin synthesis through a dual mechanism by inhibiting TYR-catalyzed dopaquinone synthesis and by diverting the synthesized dopaquinone to the formation of DOPA-cysteinamide conjugates rather than dopachrome. Finally, L-cysteinamide was shown to increase pheomelanin content while decreasing eumelanin and total melanin contents in MNT-1 cells. This study suggests that L-cysteinamide has an optimal structure that can effectively and safely inhibit eumelanin synthesis in MNT-1 cells and HEMs, and will be useful in controlling skin hyperpigmentation

Marine Alga Ecklonia cava Extract and Dieckol Attenuate Prostaglandin E2 Production in HaCaT Keratinocytes Exposed to Airborne Particulate Matter

Atmospheric particulate matter (PM) is an important cause of skin damage, and an increasing number of studies have been conducted to discover safe, natural materials that can alleviate the oxidative stress and inflammation caused by PM. It has been previously shown that the extract of Ecklonia cava Kjellman, a perennial brown macroalga, can alleviate oxidative stress in epidermal keratinocytes exposed to PM less than 10 microns in diameter (PM10). The present study was undertaken to further examine the anti-inflammatory effects of E. cava extract and its major polyphenolic constituent, dieckol. HaCaT keratinocytes were exposed to PM10 in the presence or absence of E. cava extract or dieckol and analyzed for their viability, prostaglandin E2 (PGE2) release, and gene expression of cyclooxygenase (COX)-1, COX-2, microsomal prostaglandin E2 synthase (mPGES)-1, mPGES-2, and cytosolic prostaglandin E2 synthase (cPGES). PM10 treatment decreased cell viability and increased the production of PGE2, and these changes were partially abrogated by E. cava extract. E. cava extract also attenuated the expression of COX-1, COX-2, and mPGES-2 stimulated by PM10. Dieckol attenuated PGE2 production and the gene expression of COX-1, COX-2, and mPGES-1 stimulated by PM10. This study demonstrates that E. cava extract and dieckol alleviate airborne PM10-induced PGE2 production in keratinocytes through the inhibition of gene expression of COX-1, COX-2, mPGES-1, and/or mPGES-2. Thus, E. cava extract and dieckol are potentially useful natural cosmetic ingredients for counteracting the pro-inflammatory effects of airborne PM