• Radiation Oncology Journal
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• v.26 no.3
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• pp.166-172
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• 2008

Purpose: The measurement of radiosensitivity of individuals is useful in radiation therapy. Unfortunately, the measurement of radiation survival using a clonogenic assay, which is the established standard, can be difficult and time consuming. The aim of this study is to compare radiosensitivity results obtained from the MTT and clonogenic assays, and to evaluate whether the MTT assay can be used on clinical specimens. Materials and Methods: HCT-8, LoVo, CT-26, and WiDr were the colon cancer cell lines used for this study. The clonogenic assay was performed to obtain the cell survival curves and surviving fractions at a dose of 2 Gy ($SF_2$) as the standard technique for radiosensitivity. Also, the MTT assay was performed for each of the cell lines (in vitro). To simulate clinical specimens, the cell lines were inoculated into nude mice, removed when the tumors reached 1 cm in diameter, and chopped. Next, the tumors were subjected to the same process involved with the MTT assay in vitro. The inhibition rates (IR) of 10 Gy or 20 Gy of irradiation for in vitro and ex vivo were calculated based on the optical density of the MTT assay, respectively. Results: According to $SF_2$ and the cell survival curve, the HCT-8 and WiDr cell lines were more resistant to radiation than LoVo and CT-26 (p<0.05). The IR was measured by in vitro. The MTT assay IR was 17.3%, 21%, 30% and 56.5% for the WiDr, HCT-8, LoVo and CT-26 cell lines, respectively. In addition, the IR measured ex vivo by the MTT assay was 23.5%, 26%, 38% and 53% in the HCT-8, WiDr, LoVo and CT-26 tumors, respectively. Conclusion: The radiosensitivity measured by the MTT assay was correlated with the measures obtained from the clonogenic assay. This result highlights the possibility that the MTT assay could be used in clinical specimens for individual radiosensitivity assays.

• Radiation Oncology Journal
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• v.19 no.2
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• pp.163-170
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• 2001

Purpose : The measurement of radiation survival using a clonogenic assay, the established standard, can be difficult and time consuming. In this study, We have used the MTT assay, based on the reduction of a tetrazolium salt to a purple formazan precipitate by living cells, as a substitution for clonogenic assay and have examined the optimal condition for performing this assay in determination of radiation sensitivity. Materials and Methods : Four human cancer cell lines - PCI-1, SNU-1066, NCI-H630 and RKO cells have been used. For each cell line, a clonogenic assay and a MTT assay using Premix WST-1 solution, which is one of the tetrazolium salts and does not require washing or solubilization of the precipitate were carried out after irradiation of 0, 2, 4, 6, 8, 10 Gy. For clonogenic assay, cells in $25\;cm^2$ flasks were irradiated after overnight incubation and the resultant colonies containing more than 50 cells were scored after culturing the cells for $10\~14$ days. For MTT assay, the relationship between absorbance and cell number, optimal seeding cell number, and optimal timing of assay was determined. Then, MTT assay was performed when the irradiated cells had regained exponential growth or when the non-irradiated cells had undergone four or more doubling times. Results : There was minimal variation in the values gained from these two methods with the standard deviation generally less than $5\%$, and there were no statistically significant differences between two methods according to t-test in low radiation dose (below 6 Gy). The regression analyses showed high linear correlation with the $R^2$ value of $0.975\~0.992$ between data from the two different methods. The optimal cell numbers for MTT assay were found to be dependent on plating efficiency of used cell line. Less than 300 cells/well were appropriate for cells with high plating efficiency (more than $30\%$). For cells with low plating efficiency (less than $30\%$), 500 cells/well or more were appropriate for assay. The optimal time for MTT assay was after 6 doubling times for the results compatible with those of clonogenic assay, at least after 4 doubling times was required for valid results. In consideration of practical limits of assay (12 days, in this study) cells with doubling time more than 3 days were inappropriate for application. Conclusion : In conclusion, it is found that MTT assay can successfully replace clonogenic assay of tested cancer cell lines after irradiation only if MTT assay was undertaken with optimal assay conditions that included plating efficiency of each cell line and doubling time at least.

• Korean Journal of Food Science and Technology
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• v.43 no.6
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• pp.754-759
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• 2011

Zinc protoporphyrin (ZnPP) is produced endogenously during heme metabolism and treated in cells as a heme oxygenase inhibitor. In the present study, the effects of ZnPP on the color response of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, a commonly-used method for analyzing cell viability, were investigated. ZnPP induced rapid decolorizaion of MTT formazan under light; the degradation rates were 10- and 20- folds faster in the presence of 5 and $10{\mu}M$ ZnPP, respectively. Methylene blue (MB), another type of photosensitizer, also accelerated degradation of formazan under light. Butylated hyroxytoluene did not inhibit ZnPP- or MB-induced formazan degradation. The color degradation of formazan dye was signficantly delayed in the presence of N-acetylcysteine or ${\beta}$-carotene. The present results suggest that certain photosensitizing compounds may affect the color and stability of MTT formazan, which should be carefully considered when conducting the MTT assay.

• Journal of the Korean Society for Railway
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• v.11 no.4
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• pp.384-389
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• 2008

The ballast, one of track components, plays an essential role as intermedium in transmitting train load to subgrade safely, and the deterioration of ballast directly effects the growth of track irregularity. In this study, we determined the main factor of ballast deterioration was miniature of ballast gravel caused MTT (Multiple Tie Tamper) works and accumulated traffic loads. To estimate the deterioration characteristics of ballast, we carried out field test (Chap.2) through track construction for test and the model test (Chap.3) simulating the actual operation environment, have done a comparative analysis with the sample's result (crushing rate) of high-speed railroad running actually.

• Journal of Food Hygiene and Safety
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• v.17 no.4
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• pp.188-192
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• 2002

The phototoxicity inhibitory activity of 15 natural products having antiinflammatory effect was screened by three in vitro methods : yeast growth inhibition test with Candida albicans, RBC photohemolysis and MTT assay. We induced phototoxic reaction by irradiating UVB (312 nm) on chlorpromazine (CPZ) that has been widely documented as phototoxic agent in clinical and experimental studies and then observed the effects of the natural products after treating them with CPZ. In yeast growth Inhibition test, P. persica and E. officinalis showed the inhibitory effect on the UVB phototoxicity and E. officinalis, yeast, P. suffruticosa showed phototoxicity inhibitory effect in that their ％ hemolysis compared with control were 45.76 $\pm$ 0.91, 34.42$\pm$1.01, 35.30 $\pm$4.76 on UVB. In MTT assay, all tested natural products increased cell viability compared with the contort.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.24 no.2
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• pp.249-260
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• 1994

The purpose of this study was to aid in the radiation therapy of head and neck cancer patients. For this study, radiation survival curves were generated for Bl6, MG-63 and YAC-l cell lines using semiautomated MTT assay and Dye Exclusion Assay. Irradiation of 2, 4, 6, 8, 10Gy were delivered at room temperature at a dose rate of 210.2cGy/min using / sup 60/Co γ-ray Irradiator ALOORAOO 8. The viable cells were determined for each radiation dose and compared to control values. The obtained results were as follows: 1. There was significantly different absorbance at 10Gy on B16 cell line in MTT assay(P<0.05). 2. There was significantly different absorbance at 4, 6, 8, 10Gy on MG-63 cell line in MTT assay(P<0.05). 3. YAC-l cell line was more sensitive than B16 or MG-63 cell line to all doses of radiation(P<0.05). 4. There was significantly different absorbance among all tumor cell lines except between B16 and MG-63 cell line at ZGy in MTT assay(P<0.05). 5. Good correlation was obtained between MTT assay and DEA(P<0.05). The efficient of correlation of B16, MG-63 and YAC-l cell line was 0.845, 0.824 and 0.906, respectively.

• The Journal of Korean Medicine
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• v.19 no.2
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• pp.326-336
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• 1998

면역 결핍 바이러스와 허피즈 바이러스 -1,2에 대한 한약의 항바이러스 작용을 관찰하기 위하여, 세포 바이러스 검색에 초기 독성과 감염 바이러스의 생존 세포 수를 비교적 단기간내 볼 수 있는 96-well plate를 이용한 MTT assay로 측정하였다. 본 실험은 예비 실험 단계에서 사용된 총 85가지의 한약중 단미제 6가지와 복합처방 44가지를 선정하였으며 복합처방은 유사한 치법으로 분류하였고 한약의 시료 추출은 순수하게 물로 전탕하여 여과하였다. 실험 결과 파두와 맥아가 면액 결핍 바이러스에 대해 감염초기 유의성이 있었으며 호장근, 갈근우방자탕과 형방패독산이 허피즈 바이러스-1,2에 대해 감염초기 유의성이 있었으나 실험의 시간 경과에 따른 지속적인 약효 안정성을 보이지는 못하였다. 이 실험을 통하여 한약을 이용한 우수한 바이러스 치료를 개발하기 위해서는 단미제나 복합 처방에서 항바이러스 작용이 큰 유효성분의 대량 분리와 세포 실험에 있어서 오차를 줄 일 수 있는 세포면역학적 실험의 도입 등이 필요할 것으로 사료된다.

• Korean Journal of Environmental Agriculture
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• v.16 no.2
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• pp.149-155
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• 1997

This study was carried out to investigate the effects of phenobarbital sodium(PB) and 3-methylcholanthrene(3-MC) on carbofuran cytotoxicity and to develop antitoxic agents based on the effectivness. Experimental groups for carbofuran cytotoxicity were divided into five groups ; medium alone and four treatments of carbofuran (1, 25, 50 and $100{\mu}M)$, and those for compensation effects were divided into six groups ; medium alone, $IC_{50}$ carbofuran and four combinations of carbofuran and PB or 3-MC($IC_{50}$ carbofuran plus 1, 25, 50, $100{\mu}M$ of PB and 3-MC, respectively). After incubation for 48 hrs under the same conditions, MTT(Tetrazolium MTT), NR(Neutral red) and SRB(Sulforhodamine B protein) assay were performed. Fifty percentage inhibition of MTT, NR, and SRB against carbofuran in rat fibroblast cell were 60.7, 82.5 and $87.0{\mu}M$, respectively. At the combination treatments of $IC_{50}$ of carbofuran and $100{\mu}M$ of PB, the significant compensation effects were observed from the results of MTT and NR but not from that of SRB absorbance. And at the combination treatments of $IC_{50}$ of carbofuran and 3-MC, the relatively significant compensation effects were found at $50{\mu}M$ 3-MC from the results of MTT and at $100{\mu}M$ 3-MC from that of NR and SRB absorbances, respectively. From the results of light microscopy, combination treatments of $carbofuran(IC_{50})$ and PB or 3-MC showed good regeneration in carbofuran toxicity of rat fibroblast cells. These results suggest that PB or 3-MC can compensate the cytotoxity of carbofuran insecticide in rat NIH3T3 fibroblast cells.

• Environmental Analysis Health and Toxicology
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• v.15 no.1_2
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• pp.13-18
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• 2000

A few in vitro methods were developed to compare the result on the phototoxicity of phenothiazines. By the MTT assay, the Candida test, and the RBC photohemolysis, the phototoxicities of UVA and UVB irradiation were measured. This paper presents the comparisons of methods which are effective to measure the phototoxicities of the chemicals causing phototoxicity and photoallergy. The tested chemicals of phenothiazines include Chlorpromazine, Promethazine, Perphenazine, Chlorprothixene, Trifluoperazine and Thioridazine. Each chemical represented variable results according to the test methods. MTT assay shows the most sensitive method.

• Environmental Analysis Health and Toxicology
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• v.17 no.3
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• pp.253-259
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• 2002

The phototoxicity inhibitory activity of 15 natural products having antiinflammatory effect was screened by three in vitro methods: yeast growth inhibition test with Candida albicans, RBC photohemolysis and MTT assay. We induced phototoxic reaction by irradiating UVA (365 nm) on chlorpromazine (CPZ) that has been widely documented as phototoxic agent in clinical and experimental studies and then observed the effects of the natural products after treating them with CPZ. In yeast growth inhibition test, X. stramonium showed the inhibitory effect on the UVA phototoxicity and E. officinalis, Yeast, P. suffruticosa showed phototoxicity inhibitory effect in that their ％ hemolysis compared with control were 36.14${\pm}$ 2.69, 42.82${\pm}$1.35, 36.41${\pm}$0.48 on UVA. In MTT assay, all tested natural products increased cell viability compared with the control.