• Environmental Mutagens and Carcinogens
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• v.17 no.2
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• pp.71-77
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• 1997

The single cell gel electrophoressis(SCGE) assay, also known as the comet assay, is a rapid, simple, visual and sensitive technique for measuring and analysing DNA breakage in mammalian cells. The SCGE or comet assay is a promising test for the detection of DNA damage and repair in individnal cells. It has widespread potential applications in DNA damage and repair studies, genotoxicity testing and biomonitoring. In this microgel electrophoresis technique, cells are embedded in agarose gel on microscope slides, iysed and electrophoresed under alkaline conditions. Cells with increased DNA damage display increased migration of DNA from the nucleus towards the anode. The length of DNA migration indicates the amount of DNA breakage in the cell. The comet assay is also capable of identifying apoptotic cells which contain highly fragmented DNA. Here we review the development of the SCGE assay, existing protocols for the detection and analysis of comets, the relevant underlying principles determining the behaviour of DNA and the potential applications of the technique.

• Environmental Mutagens and Carcinogens
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• v.21 no.1
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• pp.44-50
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• 2001

To identify nongenotoxic carcinogen determined as negative by ICH guideline-recommended standard genotoxicity test battery; Ames test, chromosome aberration assay, mouse lymphoma $tk^{+/-}$ assay, in vivo micronucleus assay, we picked bisphenol A as a model compound. In this study, we applied in vitro BalB/c 3T3 cell transformation assay and Syrian hamster embryo (SHE) cell transfarmation assay. Bisphenol A was treated upto $769.2 ug/m{\ell}$ in BalB/c 3T3 cells and upto $125 ug/m{\ell}$ in SHE cells. bisphenol A didn't induced morphological transformation both with one stage treatment protocol and with two stage treatment protocol. But, treated far 48 hr, Bisphenol A induced morphological transformation significantly in SHE cells.

• Journal of Microbiology and Biotechnology
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• v.20 no.10
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• pp.1463-1470
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• 2010

E. coli has long been widely used as a host system for the manufacture of recombinant proteins intended for human therapeutic use. When considering the impurities to be eliminated during the downstream process, residual host cell DNA is a major safety concern. The presence of residual E. coli host cell DNA in the final products is typically determined using a conventional slot blot hybridization assay or total DNA Threshold assay. However, both the former and latter methods are time consuming, expensive, and relatively insensitive. This study thus attempted to develop a more sensitive real-time PCR assay for the specific detection of residual E. coli DNA. This novel method was then compared with the slot blot hybridization assay and total DNA Threshold assay in order to determine its effectiveness and overall capabilities. The novel approach involved the selection of a specific primer pair for amplification of the E. coli 16S rRNA gene in an effort to improve sensitivity, whereas the E. coli host cell DNA quantification took place through the use of SYBR Green I. The detection limit of the real-time PCR assay, under these optimized conditions, was calculated to be 0.042 pg genomic DNA, which was much higher than those of both the slot blot hybridization assay and total DNA Threshold assay, where the detection limits were 2.42 and 3.73 pg genomic DNA, respectively. Hence, the real-time PCR assay can be said to be more reproducible, more accurate, and more precise than either the slot blot hybridization assay or total DNA Threshold assay. The real-time PCR assay may thus be a promising new tool for the quantitative detection and clearance validation of residual E. coli host cell DNA during the manufacturingprocess for recombinant therapeutics.

• BMB Reports
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• v.43 no.7
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• pp.468-473
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• 2010

Previously, various inhibitors of cell wall synthesis induced the drp35 gene of Staphylococcus aureus efficiently. To determine whether drp35 could be exploited in antistaphylococcal drug discovery, we cloned the promoter of drp35 ($P_d$) and developed different biological assay systems using an engineered S. aureus strain that harbors a chromosomally-integrated $P_d$ - lacZ transcriptional fusion. An agarose-based assay showed that $P_d$ is induced not only by the cell wall-affecting antibiotics but also by rifampicin and ciprofloxacin. In contrast, a liquid medium-based assay revealed the induction of $P_d$ specifically by the cell wall-affecting antibiotics. Induction of $P_d$ by sublethal concentrations of cell wall-affecting antibiotics was even assessable in a microtiter plate assay format, indicating that this assay system could be potentially used for high-throughput screening of new cell wall-inhibiting compounds.

• 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.

• Toxicological Research
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• v.16 no.2
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• pp.101-107
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• 2000

Cannabidiol derivatives (1, 2 and 3), 5-fluorouracil (4, 5-FU) and adriamycin (5, AM) were tested for their growth inhibitory effects against human tumor cell lines using two different 3-{4,5-dimeth-ylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay and sulforhodamine B protein (SRB) assay. The light microscopic study showed morphological changes of the treated cells. Disruptions in cell organelles were determined by colorimetric methods; MTT assay and STB assay. These results suggest that cannabidiol (1, CBD) retains the most growth-inhibitory activity against human tumor cell lines.

• Biomedical Science Letters
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• v.11 no.3
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• pp.337-341
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• 2005

This study was undertaken to clerify the cytotoxic effect of syringic acid by colorimetric assay on human cancer cells. For the evaluation of cytotoxicity of syringic acid, the cell viability and cell adhesion activity of syringic acid on cancer cells, human oral epithelioid carcinoma cells were determined using by colorimetric assays such as MTT (3-[4,5­dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay and XTT (2,3-bis-[2-methoxy-4-nitro-5-sulfophenyl]­2H-tetrazolium-5-caboxanilide) assay, respectively after human oral epithelioid carcinoma cells were treated with syringic acid for 48 hours. In this study, the cell viability of syringic acid on human oral epithelioid carcinoma cells showed a significant decrease by MTT assay compared with control, and also, the cell adhesion activity by XTT assay was decreased significantly in these cells after cells were treated with various concentrations of syringic acid for 48 hours. $MTT_{50}\;and\;XTT_{50}\;were\;282.3\;{\mu}M\;and\;418.8{\mu}M$ syringic acid, respectively. These results suggest that syringic acid shows midcytotoxic effect on human oral epithelioid carcinoma cells by the decreasement of the cell viability and the cell adehision activity assessed by colorimetric assay in these cultures.

• Restorative Dentistry and Endodontics
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• v.21 no.1
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• pp.403-424
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• 1996

Cell culture methods have been used to assess the cytotoxicity of dental materials. Different paramaters are used to monitor cytotoxic effects. But it is difficult to compare each investigator's results with different methods. The objective of this study was to investigate cytotoxic effect of several retrograde filling materials according to cell lines and assay methods. Cytotoxicity of Bestalloy (Dogmyung, Korea), Prisma APH(Densply International Inc., U.S.A.), Clearfil FII (Kuraray Co., Japan), Fuji II (GC Co., Japan), Fuji II LC (GC Co., Japan) and IRM (Densply Co., U.S.A.) on L929, 3T3 and KB permanent cell lines was measured. Radiochromium, Lactate dehydrogenase (LDH) release method and colorimetric assays, namely neutral red (NR) and MTT were used. Each material was mixed according to the manufacturer's instruction. They were tested as solid and extracted state. Cell culture media were added to each mixed or solid materials then the solution was collected and used as extract solutions. Solid Fuji II showed mild cytotoxicity on three cell lines using radiochromium release method. There was no difference in cytotoxicity of extract solution group using radiochromium release method. In colorimetric assay immediate Fuji II group and all the IRM groups showed severe cytotoxic effect. Difference in cyctotoxicity was due to rather kinds of cell lines than assay methods. Solid Fuji II and IRM showed mild cytotoxicity on three cell lines. But extract solutions had different cytotoxic effect according to cell lines using LDH release assay. Light-cured glass ionomer had mild to moderate degree of cytotoxicity on three cell lines. Cytotoxicity was affected by specimen prepaton. Susceptibility of each cell ines were also affected by assay emthods. It was suggested that cytotoxicity study using only one cell line and/or assay method might not accurately reflect the real toxic nature of dental biomaterials.

• Biomedical Science Letters
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• v.10 no.3
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• pp.269-273
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• 2004

This study was designed to investigate the effect of ferulic acid on cell viability and cell adhesion activity in normal human gingival fibroblasts. The cell viability and cell adhesion activity of ferulic acid was measured by MTT assay or XTT assay, respectively, after normal human gingival fibroblasts were treated with or without ferulic acid for 48 hours. The cell viability of ferolic acid on normal human gingival fibroblasts did not show any decreasement by MTT assay and also, cell adhesion activity did not decreased by XTT assay, respectively, compared with control after cells were treated with various concentrations of ferolic acid for 48 hours. MTT/sub 50/ and XTT/sub 50/ were 2,130.0 μM and 1,773.7 μM ferolic acid, respectively. These results suggest that ferolic acid is non-toxic to normal human gingival fibroblasts by showing no significant differences in the cell viability and the adhesion activity compared with control by colorimetric assay.

• Journal of Ginseng Research
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• v.22 no.3
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• pp.188-192
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• 1998

We established the model of clonogenic assay with human tumor cell line such as Calu-3 (lung carcinoma), HEC- lB (endometrial adenocarcinoma) , HEp-2 (larnyx carcinoma), Hs-5787 (breast carcinoma), K-562 (chronic myelogenous leukemia), SF-188 (brain carcinoma), SNU-1 (stomach carcinoma) and WiDr (colon carcinoma) . We investigated growth inhibition of solvent (EtOH, MeOH) and water (100$^{\circ}C$, 121$^{\circ}C$) extracts from Korean red ginseng by clonogenic assay. The results of clonogenic assay showed that EtOH extract had growth inhibition against Calu-3, SF-188 and SNU-1, MeOH extract had growth inhibition against Calu-3, Hs-5787, K-562, and WiDr, but water extract at 100$^{\circ}C$ and water extract at 121$^{\circ}C$ had not growth inhibition against used cell lines.