• Journal of Embryo Transfer
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• v.25 no.4
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• pp.229-235
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• 2010

The MTT assay is one of superior evaluation methods widely used to analyze the viability of metabolically active cell. It can be used to determine the percentage of viable sperm through measurement of the reduction of MTT granules at mitochondria in sperm tail. The purpose of this study is to determine the optimal condition of a simple and easy MTT assay to validate boar sperm viability and compare the accuracy of this test with microscopic examination. The MTT reduction rate for sperm viability were analyzed in microtiter plates (96 well) from 1 hr to 5 hr incubation periods at $37^{\circ}C$ using spectrophotometer (microplate reader) at 550 nm wavelength. The remainder of semen sample was simultaneously examined to compare the correlation of accuracy between MTT assay and other sperm parameters. Those sperm parameters were included the motility, survival rates, membrane integrity, mitochondria activity and acrosome integrity. The OD values of MTT assay (MTT reduction rates) did not greatly change at 1 hr to 5 hr incubation periods in different proportion of live and freeze-killed sperms (dead sperm). The MTT reduction rates or survival rates were decreased according to the different concentration of live and dead sperm. The linear regression at 1 hr and 4 hr incubation periods in sperm MTT assay was y=291.55x-72.176 and y= 180.64x-44.569, respectively. There are high correlation between 1 hr and 4 hr incubation periods (p<0.001). The results of MTT assay and other sperm parameters has a positive correlation (p<0.01 or 0.05). The correlation coefficients for MTT assay was 0.88115 for motility, 0.89868 for survival rates, 0.91722 for membrane integrity and 0.77372 for acrosome integrity, respectively. In conclusion, the MTT assay can be used as a reliable and efficient evaluation method for boar sperm viability. It can be use practical means to evaluate the quality of boar sperm by a fast, inexpensive and easy method.

• Toxicological Research
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• v.13 no.3
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• pp.251-256
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• 1997

Toluene inhalation increases glutamate level and its receptor in various brain regions. In this study, nitric oxide synthase (NOS) activities were investigated in various rat brain regions using NADPH diaphorase staining method which examined histochemical changes of NOS in the neural cells. Also, in vitro LDH leakage assay and MTT test were performed to investigate the toxic influences of toluene in cultured granule cell of rat cerebellum which was significantly affected with toluene in vivo. Rats were exposed to toluene of 10000 ppm for 3 days. 7 days and 14 days by 20 min $\times$ 2 times a day. NADPH diaphorase staining was processed in the different brain regions after inhalation. NADPH diaphorase staining density was not significantly changed at 3 days inhalation group, but the density decreased in proportion to the duration of toluene inhalation. Over 30% of staining density was decreased at 14 days group which was maximum duration of inhalation in this study. The tendency of staining density decrease was significant in granule cell of cerebellum. Cell death by toluene exposure was observed in cultured cerebellar granule cell. $EC_{50}$ measured with LDH leakage assay and MTT test were 43 mM and 72 mM respectively.

• 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 the Korean Society for Railway
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• v.2 no.3
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• pp.61-69
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• 1999

The durability of ballast plays an important role in track behaviour. To estimate the deterioration characteristics of ballast, several tests have been carried out by several scholars. The deterioration characteristics is very important factor in the behaviour of track and its life. In this paper, abrasion/breakage characteristics of ballast is studied to see the effect of physical ballast characteristics on ballast life. To reveal breakage characteristics of ballast, the ballast box test and the MTT field test were carried out. The breakage characteristics studied in this paper is applied to the ballast life prediction in various conditions, such as LA abrasion, annual tonnage, tamping number per year, etc

• Restorative Dentistry and Endodontics
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• v.19 no.2
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• pp.409-428
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• 1994

Endodontic surgery is performed when conventional endodontic therapy fails or is contraindicated. In such cases, retrograde filling materials including amalgam, composite resin, and various cements have been used. Biocompatibilty and margin sealing ability of retrograde filling materials are important for the long term success of endodontic surgery. In vitro cell culture is frequently used as the method of measuring the biocompatibilty of dental materials. The purpose of this study was to evaluate the cytotoxicity of six kinds of retrograde filling materials including newly developed light curing glass ionomer cements. Each material was mixed according to. the manufacture's instruction and evaluated as : freshly mixed, 24-hour after mixing, and 168-hour after mixing respectively. The elution solution was extracted after 24-hour contact with materials using media. Cytotoxicity was evaluated by direct contact, or elution contact. Test results of radiochromium($^{51}Cr$) release, cell viability using tetrazolium dye (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl dimethyltetrazolium bromide(MTT) test and lactate dehydrogenase(LD) of damaged L929 cells were analyzed. In the $^{51}Cr$ release of direct contact, all experimental retrograde filling materials except amalgam and glass ionomer cement showed increased cytotoxicity compared to control. In the $^{51}Cr$ release of elution solution, the released $^{51}Cr$ was so minimal that it was impossible. to evlauate the cytotoxicity exactly. The elution solutions of glass ionomer cement and IRM showed marked cytotoxicity in MTT test. LD enzyme activity was highest in tests of direct contact with composite, light curing composite, and light curing glass ionomer cement and IRM. Amalgam revealed least cytotoxicity while IRM showed cytotoxicity using all three methods. Composite, light curing composite and light curing glass iomomer cement were cytotoxic in the tests of $^{51}Cr$ release and LD activity. Glass ionomer cement showed cytotoxic effect only in the MTT method. From these results it is suggested that the standardization and optimization of cytotoxicity testing, especially using elution solutions, should be strongly advised.

• Restorative Dentistry and Endodontics
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• v.33 no.4
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• pp.332-340
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• 2008

The purpose of this study was to evaluate the viability of periodontal ligament cell in rat teeth using slow cryopreservation method with magnetic field through MTT assay and TUNEL test. For each group, 12 teeth of 4 weeks old white female Sprague-Dawley rat were used for MTT assay, and 6 teeth in TUNEL test. The Maxillary left and right, first and second molars were extracted as atraumatically as possible under tiletamine anesthesia. The experimental groups were group1 (immediately extraction), group 2 (cold preservation at 4$^{\circ}C$ for 1 week), group 3 (rapid cryopreservation in liquid nitrogen), group 4 (slow cryopreservation with magnetic field of 1 G), and group 5 (slow cryopreservation). F medium was used as preservation medium and 10% DMSO as cryoprotectant. After preservation and thawing, the MTT assay and TUNEL test were processed. One way ANOVA and Scheffe method were performed at the 95% level of confidence. The value of optical density obtained after MTT analysis was divided by the value of eosin staining for tissue volume standardization. In both MTT assay and TUNEL test, it had showed no significant difference among group 3, 4, and 5. And group 3 had showed higher viability of periodontal ligament cell than group 2. From this study, slow cryopreservation method with magnetic field can be used as one of cryopreservation methods.

• Restorative Dentistry and Endodontics
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• v.31 no.3
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• pp.192-202
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• 2006

The purpose of this study was to examine the viability of PDL cells in rat molars by using in vivo MTT assay, which was used to compare fast cryopreservation group by liquid nitrogen $(-196^{\circ}C)\;with\;4^{\circ}C$ cold preservation group. A total of 74 Sprague-Dawley white female rats of 4 week-old with a body weight of 100 grams were used. The maxillary left and right, first and second molars were extracted as atraumatically as possible under ketamine anesthesia. Ten teeth of each group were divided as six experimental groups depending upon the preservation. Cryopreservation groups were Group 1 (5% DMSO 6% HES in F medium) Group 2 (10% DMSO in F medium), Group 3 (5% DMSO 6% HES in $Viaspan^(R)$). Group 4 (10% DMSO in $Viaspan^(R)$) which were cryopreserved for 1 week and cold preservation groups were Group 5 (F medium) , Group 6 ($Viaspan^(R)$) at $4^{\circ}C$ for 1 week. Immediate extraction group was used as a control. After preservation and thawing, the in vivo MTT assay was processed. Two way ANOVA and Duncan's Multiple Range Test was performed at the 95 % level of confidence, Another 2 teeth of each group were treated as the same manner and frozen sections $10{\mu}m$ thick for microscopic observation. The value of optical density obtained after in vivo MTT analysis was divided by the value of eosin staining for tissue volume standardization. Group 1, 2 had significantly higher optical density than Group 3 and 4 which had the lowest OD value. Group 6 had higher OD value than in Group 5 (P<0.05). Histological findings of periodontal ligament cell, after being stained with MTT solution were consistent with the in vivo MTT assay results. In this study, the groups which were frozen with DMSO as a cryoprotectant and the groups with F medium showed the best results.

• Journal of Nutrition and Health
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• v.35 no.4
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• pp.439-445
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• 2002

This study was undertaken to investigate the inhibitory effect of prunus fume extracts on the growth of Hep G2 and HeLa cells. Prunus mums was extracted using the following solvents hexane, chloroform, ethylacetate, methanol, and hot water. The effect on the growth of each cancer cell line was examined by MTT (3-[4, 5-dimethylthiaeol-2-yl)-2,5-diphenyl tetrazolium bromide) assay, cytotoxicity testing, and microscopic observation. The ethylacetate extracts of Prunus muse at the concentration of 250 $\mu\textrm{g}$/ml exhibited the greatest inhibitory effect on the growth of Hep G2 in the MW assay. In cytotoxicity testing, the treatment of the Hep G2 cells with ethylacetate extracts (1000 $\mu\textrm{g}$/ml for 72 hrs) destroyed 75% of the cells, and morphological changes were also observed. futhermore, the hexane extracts of Prunes muse at the concentration of 250 $\mu\textrm{g}$/ml exhibited the greatest inhibitory effect on the growth of HeLa cells in the MTT assay. The treatment of the HeLa cells with the hexane extracts (1000 $\mu\textrm{g}$/ml for 72 hrs) resulted in the destruction of 68% of the cells. Fibroblasts were not affected by either ethylacetate or hexane extracts of prunus muse.

• Journal of Microbiology and Biotechnology
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• v.14 no.2
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• pp.395-400
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• 2004

Choristoneura fumiferana (Cf-2Cl) insect cells were cultured and immobilized by using cellulosesulfate (NaCS) and polydiallyldimethylammoniumchloride (PDADMAC). A concentration of CfMNPV (Choristoneura fumiferana multiple-mucleopolyhedrovirus) and a Cf-2Cl cell density in the microspheres have been achieved at the densities of $1.57\times10^{10}$ PIBs/ml and $7.5\times10^7$ cells/ml, respectively. Additionally, MTT-test was used to measure the viable cell density in the microspheres, and the confidence of MIT-test was investigated before and after baculovirus infection in the immobilized cell culture.

• The Korean journal of helicobacter and upper gastrointestinal research
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• v.18 no.4
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• pp.242-246
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• 2018

Background/Aims: Helicobacter pylori eradication rates using first-line treatment have decreased due to clarithromycin resistance. The aim of this study was to investigate optimal eradication regimens for patients with clarithromycin resistance in Korea. Materials and Methods: A total of 72 patients with confirmed clarithromycin resistance were enrolled from August 2015 to July 2017. Patients were randomized to a 7-day bismuth quadruple therapy (BQT) regimen or a 7-day metronidazole triple therapy (MTT) regimen. Eradication was confirmed using the $^{13}C$-urea breath test. Results: There were no differences in baseline characteristics between the groups. Intention-to-treat eradication rates were 77.8% for the BQT group and 66.7% for the MTT group (P=0.293). Per protocol eradication rates were 87.5% for the BQT group and 77.4% for the MTT group (P=0.292). Adverse events were more frequent in the BQT group. Conclusions: Eradication rates using MTT were comparable to those using BQT, and adverse events were less frequent in the MTT group. Thus, MTT may be considered as a first-line regimen for patients with clarithromycin resistance. Since this was a pilot study, a study with a large group is required.