• Biomolecules & Therapeutics
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• v.3 no.2
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• pp.122-131
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• 1995

Five human cancer cell lines (HeLa S3, Hep 3B, KATO III, Hs 683, HeLa MR) and one human normal cell line (WI-38) were examined cell viability, northern blot analysis, western blot analysis, and in situ hybridization for the expression $O_{6}$ -methylguanine-DNAmethyltransferase (MGMT), which can repair $O_{6}$ -methylguanine produced in DNA by alkylating agents. In cell viability test, the lethal sensitivities of each strain against anti-tumor drug N,N-bis(2-chloroethyl)- N-nitrosourea (BCNU) were counted, and both BCNU treated and untreated cell extracts were examined for their MGMT inducibility by RNA dot blot analysis. Cell lines did not show MGMT induction by BCNU pretreatment. Tlle MGMT activity was assayed by measuring the $^3$H radioactivity transferred from the substrate DNA containing [methyl-$^3$H)-O$_{6}$ -methylguanine to acceptor molecules in the cell extracts. Extracts from the majority of tumor strains and normal cells contained substantial MGMT activity of varying degree, while the known Mer$^{[-10]}$ cell (lacked or severely depleted in MGMT activity) Hela MR, and Hs 683 (proved to be Mer$^{[-10]}$ ) were much more sensitive to BCNU than the rest of tumor strains, as measured by cell viability test. Overall results above, KATO III showed the highest expression level of MGMT among the strains examined. Furthermore, with all the tumor and normal strains tested, a good correlation was observed between MGMT expression and cellular resistance to BCNU. The varying levels of expression of MGMT in human cancer cells found in this study should provide a molecular basis for MGMT expression among tumor strains from different tissue origin, the information of antitumor agents selection for chemotherapy of cancers.

• Animal cells and systems
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• v.9 no.4
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• pp.191-198
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• 2005

The effects of 6-aminonicotinamide (6-AN) on viability of IMR32 neuroblastoma cells in the presence of ATP or $NAD^+$ have been investigated. 6-AN caused marked reduction in cell viability and similar observations were also made with cells treated with 6-AN+ATP. However, cells treated with $6-AN+NAD^+$ showed cell viability similar to untreated cells. Morphologically, 6-AN and 6-AN+ATP treated cells showed loss of neurites, polyhedric shapes, shrinkage of cell bodies and formation of lysed cells, while $6-AN+NAD^+$ cells did not show any such changes. The flow cytometry analysis demonstrated that 6-AN increased cell population in $G_0/G_1$ phase and decreased cell population in Sand $G_2/M$ phase following a 72 h exposure. Western blot analysis showed that 6-AN stimulated a substantial increase in the level of the cdk inhibitor $p27^{kip1}$, but lowered the levels of cdk2, cyclin E and p-Rb. However, cdc25A and p53R2 were not significantly affected. Immunofluorscence staining of $p27^{kip1}$, cdk2, cyclin E and p-Rb revealed close correlation between the signal observed in the Western blot analysis. 6AN+ATP treated cells showed similar results obtained with 6-AN treated cells in expression of cdk2, cyclin E, p-Rb proteins and $p27^{kip1}$, $6-AN+NAD^+$ cells showed greater expression of cdk2, cyclin E and p-Rb than those in 6-AN and 6-AN+ATP treated cells. The results suggest that 6-AN induced the $G_0/G_1$ phase arrest in IMR32 neuroblastoma cell lines through the increase of $p27^{kip1}$ and the decrease of cdk2, cyclin E and p-Rb.

• New & Renewable Energy
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• v.20 no.1
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• pp.38-51
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• 2024

The rapid expansion of industrialization and population growth worldwide has led to a significant surge in energy demand, perpetuating heavy reliance on finite fossil fuel reserves. Although prevailing policies primarily target ground-mounted solar photovoltaics, there is a noticeable increase in the adoption of floating solar power generation systems on water surfaces. Nonetheless, adequate studies and legislative reviews on offshore solar photovoltaics in Korea are lacking. The absence of well-defined criteria for the economic analysis of floating solar photovoltaics presents hurdles to their economic feasibility. This study conducted a comprehensive cost-benefit analysis of offshore photovoltaics to evaluate their economic viability and compared four types of solar photovoltaics based on the operating area and technology: ground-mounted, floating on inland water, pontoon-based offshore, and flexible system offshore. Perspectives from both central and local government entities, emphasizing social aspects, as well as inputs from private companies with a financial focus were considered. The findings revealed variations in economic viability depending on the operating area and technology employed. This study aims to contribute to the advancement of market maturity and technology within the realm of offshore solar photovoltaics.

• Korean Journal of Environmental Biology
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• v.27 no.1
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• pp.73-81
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• 2009

Population viability analysis of a Gold-spotted pond frog (Rana chosenica) population at Cheongwon-gun, Chungbuk, in South Korea was conducted and we proposed several suggestions for effective conservation and re-introduction of the species. Simulating a developed model over 1,000 times predicted that the population will exist over 30 years with a relatively low growth rate of 0.113, but with a high probability of extinction as 81.1%. Population growth and extinction probability were the most greatly depended on the rate of successful metamorphosis. In the case of outbreak of amphibian diseases such as Chytridiomycosis and Ranavirus, the population will be easily extinct within 4 years with 100% probability. In a habitat of which carrying capacity is 200, to successfully re-introduce an extinct population, it is initially needed to put 100 individuals of which 83% is males and its age structure is normal-distributed. If we additionally conducts artificial supplementation of 10% individuals every 2 years from 4 years to 10 years after initial reintroduction, the population will become a stable with 0.297 growth rate and 0.290 extinction rate. Our results are the first case of amphibian population viability analysis in Korea and could be used to develop effective conservation and re-introduction plans for endangered Gold-spotted pond frog.

• Journal of Korean Society of Forest Science
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• v.112 no.4
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• pp.442-450
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• 2023

This study sought to determine the desiccation tolerance and storage behavior of Sarcandra glabra seeds to assist in the establishment of an ex-situ conservation strategy for the species. The basic germination characteristics of S. glabra seeds were investigated. Subsequently, the seeds were dried to various desiccation levels to allow for analysis of their germination characteristics and seed integrity. In addition, the seeds were subjected to germination tests after being stored for different durations. The initial seed moisture content following the removal of the fleshy fruit was 32.8%, and the fresh seeds maintained their seed viability even after a decrease in the seed moisture content to 4.8%, while the germination percentage was 81.0%. The germination percentage of the seeds decreased to 55.0% and 30.0% when they were desiccated to moisture contents of 2.3% and 2.2%, respectively. By contrast, when the stored seeds were desiccated, they maintained their seed viability and vigor at a moisture content of 18.6%; however, when the moisture content decreased below 5.0%, both the seed viability and vigor significantly declined and the germination percentage fell below 20.0%. Furthermore, analysis of the seed leachate revealed that the decrease in the seed viability and vigor was associated with both increased electrical conductivity and increased concentrations of inorganic compounds such as potassium and calcium. In conclusion, the findings of this study show S. glabra seeds to possess desiccation tolerance that falls somewhere between the recalcitrant and intermediate seed types, with the observed variations depending on the degree of deterioration.

• The Journal of Korean Medicine
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• v.20 no.2
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• pp.88-97
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• 1999

To characterize the effects of Gilgyung-Tang(GGT) on cellular proliferation and viability of normal lung fibroblast cells, we examined the cell cycle progression and cell cycle-related gene expression in T3891 using a flow cytometry and a quantitative RT-PCR analysis. 1. The significant surpression effect of cellular proliferations of GGT was observed in proportion to a certain concentration and time. 2. GGT was identified to induce apoptotic death of damaged cells by treatment with a DNA-damage agent and etoposide, while it stimulated the recovery of cellular viability of normal cells. 3 The significant reductions of mRNA expression of PCAN, c-Fos treated by GGT were observed. 4. The significant inductions of mRNA expression of p53, CDKN1. Gadd45 treated by GGT were observed. 5. The apoptosis caused by the reduction of Bcl-2 genes was significant and the Bax genes were increased. but the amount of Fas genes were not changed. These results strongly suggest that GGT triggers arrest of the cell cycle at G1 phase, and thus causes an inhibition of cellular proliferation of human normal lung cells through the transcriptional up-regulation of cell cycle inhibitory genes and down-regulation of induction of cell cycle stimulating genes respectably.

• The Korean Journal of Physiology and Pharmacology
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• v.16 no.4
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• pp.225-230
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• 2012

We investigated the effects of ${\beta}$-glucan purified from Paenibacillus polymyxa JB115 on the viability and proliferation of splenocytes. Splenocytes play a critical role in host immunity. MTT assays and trypan blue exclusion tests revealed that ${\beta}$-glucan significantly promoted the viability and proliferation of splenocytes over a range of concentrations. However, there was no specific subset change. ${\beta}$-glucan protected splenocytes from cytokine withdrawal-induced spontaneous cell death. For further mechanistic studies, ELISA assay revealed that ${\beta}$-glucan enhanced the expression of anti-apoptotic molecules and interleukin 7 (IL-7), a cytokine critical for lymphocyte survival. We also investigated the IL-2 dependency of ${\beta}$-glucan-treated splenocytes to determine if treated cells could still undergo clonal expansion. In flow cytometric analysis, ${\beta}$-glucan induced increased levels of the activation marker CD25 on the surface of splenocytes and ${\beta}$-glucan-treated splenocytes showed higher proliferation rates in response to IL-2 treatment. This study demonstrates that ${\beta}$-glucan can enhance the survival of splenocytes and provides valuable information to broaden the use of ${\beta}$-glucan in research fields.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.4
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• pp.1639-1642
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• 2014

The multidrug resistance phenotype is one of the major problems in development of cancer cell resistance to chemotherapy. Some natural compounds from medicinal plants have demonstrated promising capacity in enhancing anticancer effects in drug resistant cancer cells. We aimed to investigate whether mangiferin might have an ability to re-sensitize MCF-7 breast cancer cells previously treated with short-term doxorubicin in vitro, through the modulation of efflux transporters, P-glycoprotein (P-gp), MRP1 and BCRP. We exposed MCF-7 breast cancer cells pretreated with doxorubicin for 10 days to mangiferin (10, 25 or 50 ${\mu}M$) for 96 hours. Afterwards, we evaluated influence on cell viability and level of mRNA expression of P-gp, MRP1 and BCRP. Doxorubicin given in combination with mangiferin at low concentrations (10 and 25 ${\mu}M$) failed to give significant reduction in cell viability, while at the highest concentrations, the combination significantly reduced cell viability. The mRNA expression analysis of P-gp, MRP1 and BCRP showed that mangiferin had inhibitory effects on P-gp but no effects on MRP1 and BCRP. In conclusion, we suggest that mangiferin at high concentrations can be used as chemosensitizer for doxorubicin therapy. This effect might be attributed by inhibitory effects of mangiferin on P-glycoprotein expression.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.5
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• pp.255-259
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• 2003

Dendritic cells (DCs) play a critical role in various immune responses involving $CD4^+$ T cells and have been used to generate anti-tumor immunity. Chemotherapy induces severe side effects including immunosuppression in patients with cancer. Although immunosuppression has been studied, the effects of anticancer drugs on DCs are not fully determined. In this study, we demonstrated that CD40 activation strongly protected DCs from 5-fluorouracil (5-FU) or mitomycin C-induced apoptosis. DCspecific surface markers, including CD11c and major histocompatibility complex (MHC) class II, were used for identifying DCs. CD 40 activation with anti-CD40 mAb significantly enhanced the viability of DCs treated with 5-FU or mitomycin C, assayed by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide). Fluorescence staining and analysis clearly confirmed the enhancing effect of anti-CD40 mAb on the viability of DCs, suggesting that CD40 activation may transduce critical signals for the viability of DCs. Annexin V staining assay showed that CD40 significantly protected DCs from 5-FU or mitomycin C-induced apoptosis. Taken together, this study shows that CD40 activation with anti-CD40 mAb has strong anti-apoptosis effect on DCs, suggesting that CD40 activation may overcome the immunosuppression, especially downregulation of number and function of DCs in chemotherapy-treated cancer patients.

• Applied Microscopy
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• v.28 no.4
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• pp.591-601
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• 1998

The neurotoxic effects of radiation have been studied in NSC-34 hybrid cells derived from embryonic mouse spinal cord cells. NSC-34 cells irradiated at 25Gy were decreased the cell viability in a time and dose dependent manner. The decrease in cell viability induced by the irradiation was blocked by catalase. Antagonists of the N-methyl-D-aspartate (NMDA) receptor, including D-2-amino-5-phosphonovaleric acid (APV) and chlorokynurenic acid (CKA), similarly blocked radiational induced in cell viability. We performed morphological analysis of light and electron microscope. NSC-34 cells irradiated at 25Gy were decreased the cell density and increased lysosomes and vacuoles in the cytoplasm. Especially chromatin modification was observed. These results indicated that radiation was involved in the oxidant-initiated neurotoxicity and the compounds catalase, APV and CKA were shown to be neuroprotective against radiation.