• Title/Summary/Keyword: protection mechanisms

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Inhibitory effects of persimmon (Diospyros kaki Thumb.) against diet-induced hypertriglyceridemia/hypercholesterolemia in rats (떫은감 (Diospyros kaki Thumb.)이 흰쥐의 식이성 이상지질혈증에 미치는 영향)

  • Ahn, Youngsook;Regu, Geberea manuel Meron;Oh, Eun Kyoung;Kwon, Oran
    • Journal of Nutrition and Health
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    • v.50 no.3
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    • pp.225-235
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    • 2017
  • Purpose: This study aimed to investigate the potential of freeze-dried persimmon powder (Diospyros kaki Thumb.) to protect against dyslipidemia induced by a high-fat/cholesterol diet (HFD) in a rat model. Methods: Fifty Wistar rats were randomly divided into five groups: normal control (NC), high-fat/cholesterol control (HC), tannin in HFD (HT, 1% of diet), immature persimmon in HFD (HI, 7% of diet), and mature persimmon in HFD (HM, 7% of diet). Tannin was used as a positive control. Biochemical, molecular, and histopathological changes were observed in the blood and liver. Results: We confirmed that a high fat/cholesterol diet successfully induced dyslipidemia, which was characterized by significantly altered lipid profiles in the plasma and liver. However, oxidized low-density lipoprotein levels, histopathological damage in the liver, and hepatic triglyceride levels were significantly reduced in all HT, HI, and HM groups compared to those in the HF group. In contrast, plasma apolipoprotein B level was significantly reduced only in the HT and HM groups, whereas reduction of the LDL-C level was detected only in the HI group. Although HF-induced sterol regulatory element-binding protein (SREBP) gene expression was significantly reduced in all treated groups, downstream gene expression levels varied among the different groups; significant reduction of fatty acid synthase (FAS) and 3-hydroxy-3-methylglutaryl-CoA (HMGCR) gene expression was detected only in the HI group, whereas cholesterol $7{\alpha}$-hydroxylase (CYP7A1) gene expression was significantly elevated only in the HM group. Conclusion: Taken together, the data suggest that protection of LDL oxidation and hepatic lipogenesis might be, at least partly, attributed to tannin in persimmons. However, the identified mechanisms varied up to the maturation stage of persimmon. In the case of immature persimmon, modulation of FAS and HMGCR gene expression was prominent, whereas in the case of mature persimmon, modulation of CYP7A1 gene expression was prominent.

Management Guidelines and the Structure of Vegetation in Natural Monuments Koelreuteria Paniculata Community (천연기념물 모감주나무군락의 식생구조와 관리제언)

  • Shin, Byung Chul;Lee, Won Ho;Kim, Hyo Jeong;Hong, Jeum Kyu
    • Korean Journal of Heritage: History & Science
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    • v.43 no.1
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    • pp.100-117
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    • 2010
  • This study analyzed vegetation structure of natural monuments Koelreuteria paniculata community in search of a conservation and management plan. Plant sociological analysis of Koelreuteria paniculata community indicates that it can be classified into Achyranthes japonica subcommunity and Rhodotypos scandens subcommunity and Trachelospermum asiaticum var. intermedium subcommunity. While Koelreuteria paniculata community of Ahnmyeondo is composed of sub tree layer and herb layer, those of Pohang and Wando are composed of tree layer, Sub tree layer, shrub layer, herb layer. The results of tree vitality analysis showed that those in Ahnmyeondo appeared to be relatively low when compared to those in Pohang and Wando-gun. This can be understood in two different aspects: disease and insects vulnerability due to a relatively simple structure and lack of competitive species, and decreased vitality / natural branch losses due to crown competition arising from high density. The result of soil characteristics analysis showed that soil texture, soil pH, organic matter, $p_2O_5$, exchange positive ion were sufficient for tree growth while total nitrogen was not, so that discretion would be needed for fertilizer application. As there were damages of disease and inscet, but only for 10~15% of the entire area; it still requires consistent preconsideration. The study suggests the management methods for preservation of Koelreuteria paniculata community. First, securing designated areas is necessary in order to minimize environment deterioration due to surrounding development. Especially, for sections with decreased areas, expansion of designated areas through land purchase should also be considered. Second, artificial interference may affect the livestock. Therefore, monitoring of artificial interference is necessary, based on which protection projects must be conducted. Third, from analysis of young plants which influence the maintenance mechanisms of Koelreuteria paniculata community, a decrease compared to the prior year was observed; investigation is needed. Therefore, an active management policy through status examination of livestock such as germination and young plants is necessary.

Ethanol Extract of Glycyrrhiza uralensis Protects Against Oxidative Stress-induced DNA Damage and Apoptosis in Retinal Pigment Epithelial Cells (망막색소상피세포에서 감초 추출물의 산화적 스트레스에 의한 DNA 손상 및 apoptosis 유발의 차단 효과)

  • Kim, So Young;Kim, Jeong-Hwan;Kim, Sung Ok;Park, Seh-Kwang;Jeong, Ji-Won;Kim, Mi-Young;Lee, Hyesook;Cheong, JaeHun;Choi, Yung Hyun
    • Journal of Life Science
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    • v.29 no.11
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    • pp.1273-1280
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    • 2019
  • Age-related macular degeneration (AMD) is one of the leading causes of blindness in the elderly population, and damage to retinal pigment epithelial (RPE) cells due to oxidative stress contributes to the development of AMD. Glycyrrhiza uralensis Fischer is one of the most widely used herbal medicines for the treatment of various diseases in Asian countries. Although recent studies indicated that treatment with G. uralensis can protect cells from oxidative stress, its mechanisms in RPE cells remain unknown. We evaluated the effect of a G. uralensis ethanol extract (GU) on $H_2O_2$-induced oxidative injury in ARPE-19 RPE cells. The GU pretreatment attenuated reactive oxygen species (ROS) generation induced by $H_2O_2$, which was associated with induced expression of nuclear factor erythroid-derived-2-like 2 (Nrf2) and heme oxygenase-1 (HO-1). GU also suppressed $H_2O_2$-induced DNA damage and mitochondrial dysfunction. The inhibitory effect of GU on $H_2O_2$-induced apoptosis was associated with the protection of caspase-3 activation. Overall, GU appeared to protect RPE cells from oxidative injury by inhibiting DNA damage and reducing apoptosis. Further studies are needed to determine the regulation of Nrf2-mediated HO-1 expression, but our results suggest the possibility of using GU to reduce the risk of AMD.

Significance and Limitation of the Guiding Principles for the Preparation of Nominations Concerning Sites of Memory Associated with Recent Conflicts (최근 갈등과 관련된 기억유산의 등재 준비를 위한 지침원칙의 의의와 한계)

  • HEO Sujin
    • Korean Journal of Heritage: History & Science
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    • v.57 no.3
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    • pp.162-182
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    • 2024
  • Since the adoption of the World Heritage Convention, sites associated with dark histories have been inscribed as World Heritage sites over the past fifty years. However, in 2018, the review of nomination dossiers for these sites was temporarily suspended to prevent additional discomfort or the conflicts these inscriptions might cause. Despite concerns raised by experts about nominations of these sites, the increasing demands from State Parties led to the adoption of the Guiding Principles for the Preparation of Nominations Concerning Sites of Memory Associated with Recent Conflicts. These Guiding Principles have made it possible to inscribe such sites as World Heritage sites. The Guiding Principles play a crucial role in outlining the nature and criteria for inscription, the components required in the nomination dossier, and mechanisms for notifying a contestation in cases of differing interpretations of the site. Their primary aim is to minimize further conflicts that may arise from the inscription of sites of memory. They affirm that such sites can contribute to achieving the objectives of the World Heritage Convention and represent a significant step in addressing heritage interpretation in the World Heritage system. The amendment of the Operational Guidelines to incorporate a contestation mechanism has arguably established a more transparent and open inscription process. However, the Guiding Principles also have limitations. Among the ten criteria set by the World Heritage Convention, sites related to conflicts or dark histories can use Criterion (vi). This criterion focuses on the site's outstanding universal value linked to historical events or associations, regardless of physical evidence. If a State Party chooses not to use Criterion (vi), the application of the Guiding Principles cannot be expected. Furthermore, while the Guiding Principles require a heritage interpretation strategy in the nomination dossier, the lack of detailed guidance may confuse nominating countries. Sites of memory associated with recent conflicts are not just places that need protection and remembrance due to their association with dark histories. They have also evolved to become spaces for reconciliation and healing. The inscription of these sites as World Heritage sites is not just a recognition of their historical significance, but also a platform for discussing the impact of past conflicts on modern society. It opens up a dialogue on how current generations can address these issues. With the adoption of the Guiding Principles, we hope that inscribed sites will not only promote reconciliation and healing but also serve as a starting point for addressing present and future challenges.

Cardioprotective Effect of Calcium Preconditioning and Its Relation to Protein Kinase C in Isolated Perfused Rabbit Heart (적출관류 토끼 심장에서 칼슘 전처치에 의한 심근보호 효과와 Protein Kinase C와의 관계)

  • 김용한;손동섭;조대윤;양기민;김호덕
    • Journal of Chest Surgery
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    • v.32 no.7
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    • pp.603-612
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    • 1999
  • Background : It has been documented that brief repetitive periods of ischemia and reperfusion (ischemic preconditioning, IP) enhances the recovery of post-ischemic contractile function and reduces infarct size after a longer period of ischemia. Many mechanisms have been proposed to explain this process. Recent studies have suggested that transient increase in the intracellular calcium may have triggered the activation of protein kinase C(PKC); however, there are still many controversies. Accordingly, the author performed the present study to test the hypothesis that preconditioning with high concentration of calcium before sustained subsequent ischemia(calcium preconditioning) mimics IP by PKC activation. Material and Method : The isolated hearts from the New Zealand White rabbits(1.5∼2.0 kg body weight) Method: The isolated hearts from the New Zealand White rabbits(1.5∼2.0 kg body weight) were perfused with Tyrode solution by Langendorff technique. After stabilization of baseline hemodynamics, the hearts were subjected to 45-minute global ischemia followed by a 120-minute reperfusion with IP(IP group, n=13) or without IP(ischemic control, n=10). IP was induced by single episode of 5-minute global ischemia and 10-minute reperfusion. In the Ca2+ preconditioned group, perfusate containing 10(n=10) or 20 mM(n=11) CaCl2 was perfused for 10 minutes after 5-minute ischemia followed by a 45-minute global ischemia and a 120-minute reperfusion. Baseline PKC was measured after 50-minute perfusion without any treatment(n=5). Left ventricular function including developed pressure(LVDP), dP/dt, heart rate, left ventricular end-diastolic pressure(LVEDP) and coronary flow(CF) was measured. Myo car ial cytosolic and membrane PKC activities were measured by 32P-${\gamma}$-ATP incorporation into PKC-specific pepetide. The infarct size was determined using the TTC (tetrazolium salt) staining and planimetry. Data were analyzed using one-way analysis of variance(ANOVA) variance(ANOVA) and Tukey's post-hoc test. Result: IP increased the functional recovery including LVDP, dP/dt and CF(p<0.05) and lowered the ascending range of LVEDP(p<0.05); it also reduced the infarct size from 38% to 20%(p<0.05). In both of the Ca2+ preconditioned group, functional recovery was not significantly different in comparison with the ischemic control, however, the infarct size was reduced to 19∼23%(p<0.05). In comparison with the baseline(7.31 0.31 nmol/g tissue), the activities of the cytosolic PKC tended to decrease in both the IP and Ca2+ preconditioned groups, particularly in the 10 mM Ca2+ preconditioned group(4.19 0.39 nmol/g tissue, p<0.01); the activity of membrane PKC was significantly increased in both IP and 10 mM Ca2+ preconditioned group (p<0.05; 1.84 0.21, 4.00 0.14, and 4.02 0.70 nmol/g tissue in the baseline, IP, and 10 mM Ca2+ preconditioned group, respectively). However, the activity of both PKC fractions were not significantly different between the baseline and the ischemic control. Conclusion: These results indicate that in isolated Langendorff-perfused rabbit heart model, calcium preconditioning with high concentration of calcium does not improve post-ischemic functional recovery. However, it does have an effect of limiting(reducing) the infart size by ischemic preconditioning, and this cardioprotective effect, at least in part, may have resulted from the activation of PKC by calcium which acts as a messenger(or trigger) to activate membrane PKC.

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A Study on the Meaning of Outer Space Treaty in International Law (우주조약의 국제법적 의미에 관한 연구)

  • Kim, Han-Taek
    • The Korean Journal of Air & Space Law and Policy
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    • v.28 no.2
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    • pp.223-258
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    • 2013
  • 1967 Outer Space Treaty(Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies; OST) is a treaty that forms the basis of international space law. OST is based on the 1963 Declaration of Legal Principles Governing the Activities of States in the Exploration and Use of Outer Space announced by UNGA resolution. As of May 2013, 102 countries are states parties to OST, while another 27 have signed the treaty but have not completed ratification. OST explicitly claimed that the Moon and Other Celestial Bodies are the province of all mankind. Art. II of OST states that "outer space, including the Moon and other celestial bodies, is not subject to national appropriation by claim of sovereignty, by means of use or occupation, or by any other means", thereby establishing res extra commercium in outer space like high seas. However 1979 Moon Agreement stipulates that "the moon and its natural resources are the Common Heritage of Mankind(CHM)." Because of the number of the parties to the Moon Agreement(13 parties) it does not affect OST. OST also established its specific treaties as a complementary means such as 1968 Rescue Agreement, 1972 Liability Convention, 1975 Registration Convention. OST bars states party to the treaty from placing nuclear weapons or any other weapons of mass destruction in orbit of Earth, installing them on the Moon or any other celestial body, or to otherwise station them in outer space. It exclusively limits the use of the Moon and other celestial bodies to peaceful purposes and expressly prohibits their use for testing weapons of any kind, conducting military maneuvers, or establishing military bases, installations, and fortifications. However OST does not prohibit the placement of conventional weapons in orbit. China and Russia submitted Draft Treaty on the Prevention of the Placement of Weapon in Outer Space and of the Threat or Use of Force against Outer Space Objects(PPWT) on the Conference on Disarmament in 2008. USA disregarded PPWT on the ground that there are no arms race in outer space. OST does not have some articles in relation to current problems such as space debris, mechanisms of the settlement of dispute arising from state activities in outer space in specific way. COPUOS established "UN Space Debris Mitigation Guidelines" based on "IADC Space Debris Mitigation Guidelines" and ILA proposed "International Instrument on the Protection of the Environment from Damage Caused by Space Debris" for space debris problems and Permanent Court of Arbitration(PCA) established "Optional Rules for Arbitration of Disputes Relating to Outer Space Activities" and ILA proposed "1998 Taipei Draft Convention on the Settlement of Space Law Dispute" for the settlement of dispute problems. Although OST has shortcomings in some articles, it is very meaningful in international law in considering the establishment of basic principles governing the activities of States in the exploration and use of outer space, including the Moon and Other Celestial Bodies. OST established the principles governing the activities of states in the exploration and use of outer space as customary law and jus cogens in international law as follows; the exploration and use of outer space shall be carried out for the benefit and in the interests of all countries and shall be the province of all mankind; outer space shall be free for exploration and use by all States; outer space is not subject to national appropriation by claim of sovereignty, by means of use or occupation, or by any other means. The principles of global public interest in outer space imposes international obligations erga omnes applicable to all States. This principles find significant support in legal norms dealing with following points: space activities as the "province of all mankind"; obligation to cooperate; astronauts as envoys of mankind; avoidance of harmful contamination; space activities by States, private entities and intergovernmental organisations; absolute liability for damage cauesd by certain space objects; prohibition of weapons in space and militarization of the celestial bodies; duty of openness and transparency; universal application of the international space regime.

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