• Journal of Astronomy and Space Sciences
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• v.28 no.1
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• pp.17-26
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• 2011

Bow shock, formed by the interaction between the solar wind and a planet, is generated in different patterns depending on the conditions of the planet. In the case of the earth, its own strong magnetic field plays a critical role in determining the position of the bow shock. However, in the case of Mars of which has very a small intrinsic magnetic field, the bow shock is formed by the direct interaction between the solar wind and the Martian ionosphere. It is known that the position of the Martian bow shock is affected by the mass loading-effect by which the supersonic solar wind velocity becomes subsonic as the heavy ions originating from the planet are loaded on the solar wind. We simulated the Martian magnetosphere depending on the changes of the density and velocity of the solar wind by using the three-dimensional magnetohydrodynamic model built by modifying the comet code that includes the mass loading effect. The Martian exosphere model of was employed as the Martian atmosphere model, and only the photoionization by the solar radiation was considered in the ionization process of the neutral atmosphere. In the simulation result under the normal solar wind conditions, the Martian bow shock position in the subsolar point direction was consistent with the result of the previous studies. The three-dimensional simulation results produced by varying the solar wind density and velocity were all included in the range of the Martian bow shock position observed by Mariner 4, Mars 2, 3, 5, and Phobos 2. Additionally, the simulation result also showed that the change of the solar wind density had a greater effect on the Martian bow shock position than the change of the solar wind velocity. Our result may be useful in analyzing the future observation data by Martian probes.

• Journal of Nutrition and Health
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• v.40 no.8
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• pp.708-718
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• 2007

The purpose of this project was to evaluate whether vitamin E supplementation could improve the antioxidant status and lymphocyte DNA damage in Korean postmenopausal women. This was double blinded, placebo-controlled trial. Thirty-five subject were randomized to receive either placebo 400 mg/capsule or natural $\alpha$-tocopherol 400 IU/capsule, 2 times a day for 6 weeks. We measured plasma vitamin C, $\alpha$-tocopherol, $\gamma$-tocopherol, $\alpha$-carotenoid, $\beta$-carotenoid, lycopene concentration and tail length, %DNA in tail, tail moment in lymphocyte DNA damage index. Vitamin E supplementation group had significantly increased plasma vitamin C(p<0.05), $\alpha$-tocopherol(p<0.000), whereas $\gamma$-tocopherol(p<0.000) and tail length(p<0.05) were significantly decreased. However, placebo supplementation group also had significantly increased plasma vitamin C(p<0.05). In conclusion, our study shows that vitamin E supplementation to Korean postmenopausal women may partially improve antioxidant status and lymphocyte DNA damage.

• Journal of Nutrition and Health
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• v.39 no.7
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• pp.599-609
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• 2006

In this study, we investigated the in vivo effect by intake of the irradiated foods such as mackerel and sesame seed which are high in unsaturated fatty acid through TBARS (thiobarbituric acid reactive subtance) and the tissue pathological and genotoxicological test. Thirty two ICR mice are divided into four groups, one non-irradiated (control) group and three irradiated (5, 10, 20 kGy, respectively) groups. Sesame seed and pulverized mackerel in modified AIN93M diet were mixed together then divided into four identical parts. Three parts of them were irradiated by doses of 5, 10, and 20 kGy. These experimental diet were fed to each group for 4, 8 and] 6 weeks. The results of the study were as follows: No significant differences in weight gain were found in each group. Peroxide value of the irradiated diet was higher than that of the non-radiated one and also increased according to the storage period. TBA values in plasma, liver, kidney and Peyer's patch were not significantly different among 4 groups. DNA% in tail, tail length (TL) and tail moment (TM) values of the blood lymphocyte in 4, 8 and 16 week groups and the liver in 16 week group were much measured over the control DNA % in tail of kidney of 8 week group was significantly than the control and TL and TM of 8 week and TM of 16 week groups showed a tendency of higher values. By Peyer's DNA % in tail of 8 week group, DNA % in tail and TM of 16 week groups increased significantly over the control, Ultrastructural examination shows myeline figures and swollen mitochondria in parietal cells and intestinal epithelial cells of 8 and 16 weeks groups. After this study, we need further investigations on the safety of highly consumed foods which contain high contents of unsaturated fatty acid, largely imported and which are possible to be irradiated.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.103-103
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• 2018

Oenothera biennis, commonly known as evening primrose, a potential source of natural bioactive substances: flavonoids, steroids, tannins, fatty acids and terpenoids responsible for a diverse range of pharmacological functions. However, whether extract prepared from aerial part of O. biennis (APOB) protects skin against oxidative stress remains unknown. To investigate the protective effects of APOB against oxidative stress-induced cellular damage and elucidated the underlying mechanisms in the HaCaT human skin keratinocytes. Our results revealed that treatment with APOB prior to hydrogen peroxide ($H_2O_2$) exposure significantly increased viability, and the highest DPPH radical-scavenging activities and reducing power of HaCaT cells. APOB also effectively attenuated H2O2-induced comet tail formation and inhibited the $H_2O_2$-induced phosphorylation levels of the histone ${\gamma}H2AX$, as well as the number of apoptotic bodies and Annexin V-positive cells. In addition, APOB exhibited scavenging activity against intracellular reactive oxygen species (ROS) accumulation and restored the mitochondrial membrane potential loss by $H_2O_2$. Moreover, $H_2O_2$ enhanced the cleavage of caspase-3 and degradation of poly (ADP-ribose)-polymerase (PARP), a typical substrate protein of activated caspase-3, as well as DNA fragmentation; however, these events were almost totally reversed by pretreatment with APOB. Furthermore, APOB increased the levels of heme oxygenase-1 (HO-1), which is a potent antioxidant enzyme, associated with the induction of nuclear factor-erythroid 2-related factor 2 (Nrf2). According to our data, APOB is able to protect HaCaT cells from $H_2O_2$-induced DNA damage and cell death through blocking cellular damage related to oxidative stress through a mechanism that would affect ROS elimination and activating the Nri2/HO-1 signaling pathway.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.18
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• pp.8503-8512
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• 2016

The purpose of this study was to provide a detailed explanation of the mechanism of bisanthracycline, WP 631 in comparison to doxorubicin (DOX), a first generation anthracycline, currently the most widely used pharmaceutical in clinical oncology. Experiments were performed in SKOV-3 ovarian cancer cells which are otherwise resistant to standard drugs such as cis-platinum and adriamycin. As attention was focused on the ability of WP 631 to induce apoptosis, this was examined using a double staining method with Annexin V and propidium iodide probes, with measurement of the level of intracellular calcium ions and cytosolic cytochrome c. The western blotting technique was performed to confirm PARP cleavage. We also investigated the involvement of caspase activation and DNA degradation (comet assay and immunocytochemical detection of phosphorylated H2AX histones) in the development of apoptotic events. WP 631 demonstrated significantly higher effectiveness as a pro-apoptotic drug than DOX. This was evident in the higher levels of markers of apoptosis, such as the externalization of phosphatidylserine and the elevated level of cytochrome c. An extension of incubation time led to an increase in intracellular calcium levels after treatment with DOX. Lower changes in the calcium content were associated with the influence of WP 631. DOX led to the activation of all tested caspases, 8, 9 and 3, whereas WP 631 only induced an increase in caspase 8 activity after 24h of treatment and consequently led to the cleavage of PARP. The lack of active caspase 3 had no outcome on the single and double-stranded DNA breaks. The obtained results show that WP 631 was considerably more genotoxic towards the investigated cell line than DOX. This effect was especially visible after longer times of incubation. The above detailed studies indicate that WP 631 generates early apoptosis and cell death independent of caspase-3, detected at relatively late time points. The observed differences in the mechanisms of the action of WP631 and DOX suggest that this bisanthracycline can be an effective alternative in ovarian cancer treatment.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.7
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• pp.3035-3042
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• 2015

Background: Isorhamnetin (Iso), a novel and essential monomer derived from total flavones of Hippophae rhamnoides that has long been used as a traditional Chinese medicine for angina pectoris and acute myocardial infarction, has also shown a spectrum of antitumor activity. However, little is known about the mechanisms of action Iso on cancer cells. Objectives: To investigate the effects of Iso on A549 lung cancer cells and underlying mechanisms. Materials and Methods: A549 cells were treated with $10{\sim}320{\mu}g/ml$ Iso. Their morphological and cellular characteristics were assessed by light and electronic microscopy. Growth inhibition was analyzed by MTT, clonogenic and growth curve assays. Apoptotic characteristics of cells were determined by flow cytometry (FCM), DNA fragmentation, single cell gel electrophoresis (comet) assay, immunocytochemistry and terminal deoxynucleotidyl transferase nick end labeling (TUNEL). Tumor models were setup by transplanting Lewis lung carcinoma cells into C57BL/6 mice, and the weights and sizes of tumors were measured. Results: Iso markedly inhibited the growth of A549 cells with induction of apoptotic changes. Iso at $20{\mu}g/ml$, could induce A549 cell apoptosis, up-regulate the expression of apoptosis genes Bax, Caspase-3 and P53, and down-regulate the expression of Bcl-2, cyclinD1 and PCNA protein. The tumors in tumor-bearing mice treated with Iso were significantly smaller than in the control group. The results of apoptosis-related genes, PCNA, cyclinD1 and other protein expression levels of transplanted Lewis cells were the same as those of A549 cells in vitro. Conclusions: Iso, a natural single compound isolated from total flavones, has antiproliferative activity against lung cancer in vitro and in vivo. Its mechanisms of action may involve apoptosis of cells induced by down-regulation of oncogenes and up-regulation of apoptotic genes.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.7
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• pp.1053-1062
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• 2011

Reactive oxygen species (ROS), including singlet oxygen (${O_2}^1$), superoxide anion radical ($O_2{\cdot}^-$), hydroxyl radical ($HO{\cdot}$), peroxyl radical ($ROO{\cdot}$), hydrogen peroxide ($H_2O_2$), and hypochlorous (HOCl), are generated as byproducts of normal cellular metabolism. ROS induce damage to many biological molecules, such as lipids, proteins, carbohydrates, and DNA. It is widely believed that some degenerative diseases caused by ROS can be prevented by the high intake of fruits and vegetables due to their antioxidant activities. Recently, research on natural antioxidants has become increasingly active in various fields. Several assays have been developed to measure the total antioxidant capacity of antioxidants in fruits and vegetables in vitro. These assays include those for DPPH radical scavenging activity, SOD-like activity, total polyphenol content, oxygen radical absorbance capacity, reducing power, trolox equivalent antioxidant capacity (ABTS assay), single-cell gel electrophoresis (comet assay), and a cellular antioxidant activity assay. Because different antioxidant compounds may act through different mechanisms in vitro, no single assay can fully evaluate the total antioxidant capacity of foods. Due to the complexity of the composition of foods, it is important to be able to measure antioxidant activity using biologically relevant assays. In this review, recently used assays were selected for extended discussion, including a comparison of the advantages and disadvantages of each assay and their application to fruits and vegetables.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.10
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• pp.1244-1250
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• 2008

This study was carried out investigate the effects of chungkukjang added with onion (OC) and chungkukjang (C) on the lipid and antioxidant metabolisms of hypercholesterolemic rats. Thirty-two male Sprague-Dawley rats were divided into four groups after 1-week adaptation period and were fed a normal diet, high fat-cholesterol diet (HC), HC-OC or HC-C for 8 weeks, respectively. The supplementation of HC-OC and HC-C groups significantly reduced hepatic total cholesterol and AST activity. HC-C group increased high density lipoprotein, while decreasing low density lipoprotein and AI compared with HC-OC group. Conjugated dienes of HC-C group was significantly lower than those of HC-OC group. $H_2O_2$ induced DNA damage reduced significantly in HC-OC and HC-C groups compared with high fat-cholesterol diet group. $H_2O_2$ induced DNA damage exhibited significant positive correlations with hepatic total cholesterol, AST and CD. These results suggested that supplementation of chungkukjang or chungkukjang added with onion might be helpful in preventing lipid oxidation and leukocytic DNA damage. However, the health beneficial effect has not improved by the addtion of onion in chungkukjang.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.1
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• pp.1-9
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• 2017

Acer tegmentosum Maxim (ATM) is known as traditional medicine for treatment of hepatic disorders such as hepatitis, related-inflammatory disease, and hepatic cancer. In this study, we evaluated the antioxidant and anti-inflammatory effects of ATM extracted with $80^{\circ}C$ water or 95% ethanol. Antioxidant activities of ATM extracts were measured based on DPPH and ABTS radical scavenging activities, total polyphenolic compound contents, and ferric reducing antioxidant power. The anti-inflammatory effects of ATM extract were assayed on release of nitric oxide, tumor necrosis factor $(TNF)-{\alpha}$, and interferon $(IFN)-{\gamma}$ from lipopolysaccharide (LPS)-induced macrophages. In these experiments, 95% ethanol extract of ATM showed stronger antioxidant and anti-inflammatory effects than water extract. Therefore, we determined the effects of ATM ethanol extract on an animal model of sepsis. Seven days oral gavage of ATM ethanol extract followed by LPS stimulation reduced the protein levels of $TNF-{\alpha}$ and $IFN-{\gamma}$ in serum as well as mRNA levels of $TNF-{\alpha}$ and interleukin-6 in intestinal epithelial cells. In addition, ATM ethanol extract reduced DNA damage in mouse lymphocytes. These results indicate that ATM extract has strong antioxidant and anti-inflammatory in vitro and in vivo effects and may be developed as a potential food material for prevention of inflammatory diseases.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.1
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• pp.22-27
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• 2004

In the present study, the protective effects of Artemisia capillaris (AC) on the DNA damage induced by $^{60}$ Co ${\gamma}$-rays were evaluated using alkaline single-cell gel electrophoresis (SCGE, comet assay) in the mouse peripheral lymphocytes and micronuclei (MN) formation test in the Chinese hamster ovary (CHO) cells. We also investigated the effect of AC on 8-hydroxy-2'-deoxyguanosine (8-OHdG) formation in the mouse liver and thymus exposed to ${\gamma}$-ray, The tail moment and the frequency of MN, which were markers of DNA damage in the SCGE and MN formation test, were decreased in the groups treated with AC extract before exposure to 200 cGy of ${\gamma}$-ray. We also observed its activities, lowering 8-OHdG level, an index of oxidative DNA damage, in the groups treated with AC extract before whole body ${\gamma}$-irradiation (800 cGy). It is plausible that scavenging of free radicals by AC may have played an important role in providing the protection against the radiation-induced damage to the DNA. These results indicated that AC protects the DNA damage induced by ${\gamma}$-rays and might be a useful radioprotector, especially since it is a relatively nontoxic product.