• Bulletin of the Korean Chemical Society
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• 제30권6호
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• pp.1305-1308
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• 2009

The experimental particle samples included ($Mn_{0.1}Fe_{0.9}$)O-$Fe_2O_3$ and FeO-($Gd_{0.1}Fe_{0.9}$)$_2O_3$ with $Mn^{2+}\;and\;Gd^{3+}$ substitutions in inverse spinel $Fe_3O_4$. A lecithin surfactant was adsorbed onto the magnetic particles by ultrasonication. The samples prepared showed excellent dispersibility at the mean size of 13 nm; their saturation magnetization values were 63 emu/g for the bare and Mn-substituted magnetites, and 56 emu/g for the Gd-substituted magnetite. The crystal structure of the substituted magnetites was very similar to that of the bare magnetite, due to a small amount of 0.1 mole fraction substituted in synthesizing the magnetite. The magnetite fluids, according to T2-weighted MR images, effectively diminished the signal intensity in the liver and spleen of Sprague-Dawley rats.

• 분석과학
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• 제27권3호
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• pp.121-139
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• 2014

In this review, we will discuss aptamer technologies including in vitro selection, signal transduction mechanisms, and designing aptamers and aptazyme for label-free biosensors and catalysts. Dye-displacement, a typical label-less method, is described here which allows avoiding relatively complex labeling steps and extending this application to any aptamers without specific conformational changes, in a more simple, sensitive and cost effective way. We will also describe most recent and advanced technologies of signaling aptamer and aptazyme for the various analytical and clinical applications. Quantum dot biosensor (QDB) is explained in detail covering designing and adaptations for multiplexed protein detection. Application to aptamer array utilizing self-assembled signaling aptamer DNA tile and the novel methods that can directly select smart aptamer or aptazyme experimentally and computationally will also be finally discussed, respectively.

• Biotechnology and Bioprocess Engineering:BBE
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• 제8권2호
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• pp.64-75
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• 2003

Aptamers are functional nucleic acids that can specially bind to proteins, peptides, amino acids. nucleotides, drugs, vitamins and other organic and inorganic compounds. The aptamers are identified from random DNA or RNA libraries by a SELEX (systematic evolution of ligands by exponential amplification) process. As aptamers have the advantage, and potential ability to be released from the limitations of antibodies, they are attractive to a wide range of therapeutic and diagnostic applications. Aptamers, with a high-affinity and specificity, could fulfil molecular the recognition needs of various fields in biotechnology. In this work, we reviewed some aptamer Selection techniques, properties, medical applications of their molecules and their biotechnological applications, such as ELONA (enzyme linked oligonucleotide assay), flow cytometry, biosensors, electrophoresis, chromatography and microarrays.

• Journal of Microbiology and Biotechnology
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• 제23권6호
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• pp.878-884
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• 2013

Salmonella is a major foodborne pathogen that causes a variety of human diseases. Development of ligands directly and specifically binding to the Salmonella will be crucial for the rapid detection of, and thus for efficient protection from, the virulent bacteria. In this study, we identified a RNA aptamer-based ligand that can specifically recognize Salmonella Typhimurium through SELEX technology. To this end, we isolated and characterized an RNase-resistant RNA aptamer that bound to the OmpC protein of Salmonella Typhimurium with high specificity and affinity ($K_d$ ~ 20 nM). Of note, the selected aptamer was found to specifically bind to Salmonella Typhimurium, but neither to Gram-positive bacteria (Staphylococcus aureus) nor to other Gram-negative bacteria (Escherichia coli O157:H7). This was evinced by aptamer-immobilized ELISA and aptamer-linked precipitation experiments. This Salmonella species-specific aptamer could be useful as a diagnostic ligand against pathogen-caused foodborne sickness.

• Radiation Oncology Journal
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• 제12권3호
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• pp.301-305
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• 1994

Purpose :. To investigate the effect of aqueous extract of Ganoderma lucidum(G.I.) on the surival of tumor cells in vitro and on the growth of tumors in vivo. Materials and Methods : Dried G.I. was made into powder, extracted with distilled water, filtered and diluted from a maximum concentration of 100 mg/ml in sequence. The cytotoxicity of G.I, in vitro was evaluated from its ability to reduce the clonogenicity of SCK tumor cells. For the tumor growth delay study, about $2{\times}10^5$$ of SCK tumor cells were subcutaneously inoculated in the legs of A/J mice. The first experimental group of mice were injected i.p. with 0.2ml of 250 mg/kg of G.I. from the first day after tomor inoculation for 10 days. The second experimental group of mice were injected i.p. with 0.2ml of 250 mg/kg of G.I. either once a day for 10 days or twice a day for 5 days beginining from the 7th day after tumor inoculation Results : 1. Cytotoxicity in vitro;survival fraction, as judged from the curve, at G.I. concentration of 0.5, 1,5, 10, 25, 50 and 100 mg/ml were 1.0, $0.74{\pm}0.03$, $0.18{\pm}0.03$, $0.15{\pm}0.02$, $0.006{\pm}0.002$, 0.015 and 0.0015, respectively. 2. Tumor growth delay in vivo; a) the time required for the mean tumor volume to grow to $1,000mm^3$ was 11 days in the control group and 14 days in the experimental group. b) the time required for tumor volume to increase 4 times was 11 days in the control group while it was 10.5 and 12 days in the groups injected with G.I. once a day and twice a day from the 7th day after tumor inoculation respectively. Conclusion : Aqueous extracts of G.I. showed a marked cytotoxicity on the SCK mammary cells in vitro. Tumor growth delay was statistically signiricant when G.I. in-jection was started soon after tumor inoculation, but it was not significant when injection was started after the tumors were firmly established.

• Journal of Yeungnam Medical Science
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• 제6권1호
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• pp.59-68
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• 1989

반합성 ${\beta}$-lactam 항생제로서 여러 세균에 ${\beta}$-lactamase에 대해 높은 안정성을 나타내는 ceftizoxime의 임상 분리 장내 세균 18주에 대한 시험관대 및 생체내 항균효과와 내성균의 출현여부를 조사하고 ampicillin, tetracycline, gentamicin 및 cefadroxyl와의 항균력을 시험관내 설험으로 비교하였으며 또한 마우스 장내 정상균총에 미치는 영향을 관찰하여 다음과 같은 결론을 얻었다. 1. Ceftizoxime은 그람음성 장내 세균에 대하여 시험관내에서 높은 항균력을 나타내었으며 이러한 항균력은 ampicillin, tetracycline, gentamicin보다 높았으며 ${\beta}$-lactamase 산생 내성균주의 치료제로 알려진 cefadroxyl 보다도 높았다. 2. 시험관내 다체 내성균주는 ampicillin, cefadroxyl, gentamicin 및 tetracycline에 대한 내성주는 E. coli 1주, ampicillin, cefadroxyl 및 tetracycline에 대한 내성주는 E. coli 2주, ampicillin, gentamicin 및 tetracycline에 대한 내성주는 Shigella dysenteriae 이였으며, ampicillin 및 tetracycline에 대한 내성주는 Enterobacter cloacae였고 ampicillin 및 tetracycline에 대한 내성주는 E. coli 5주이었다. 3. Ceftizoxime에 대한 내성균주의 출현율은 매우 낮았다. 4. 서로 다른 내성을 보인 9균주 E. coli (6 strains, Shigella dysenteriae, Enterobacter cloacae, and Samonella typi)중 plasmid 분리는 6균주에서 관찰되었으며 이는 E. coli 5주와 Shigella dysenteriae 1주 있었다. 그러나 항생제에 대한 저항의 marker로서는 결정할 수 없으므로 이를 위해서는 curing experiment를 사용하여야 한다. 5. Ceftizoxime은 마우스 장내 정상균총에는 현저한 영향을 미치지 않았다. 이상의 결과에서 ceftizoxime은 그람음성 장내 세균에 대하여 높은 항균력을 나타내며 장내세균 감염치료에 선택적 항생제로 이용될 수 있을 것으로 사료된다.

• Restorative Dentistry and Endodontics
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• 제42권4호
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• pp.316-323
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• 2017

Objectives: This study compared the amount of apically extruded bacteria during the glide-path preparation by using multi-file and single-file glide-path establishing nickel-titanium (NiTi) rotary systems. Materials and Methods: Sixty mandibular first molar teeth were used to prepare the test apparatus. They were decoronated, blocked into glass vials, sterilized in ethylene oxide gas, infected with a pure culture of Enterococcus faecalis, randomly assigned to 5 experimental groups, and then prepared using manual stainless-steel files (group KF) and glide-path establishing NiTi rotary files (group PF with PathFiles, group GF with G-Files, group PG with ProGlider, and group OG with One G). At the end of canal preparation, 0.01 mL NaCl solution was taken from the experimental vials. The suspension was plated on brain heart infusion agar and colonies of bacteria were counted, and the results were given as number of colony-forming units (CFU). Results: The manual instrumentation technique tested in group KF extruded the highest number of bacteria compared to the other 4 groups (p < 0.05). The 4 groups using rotary glide-path establishing instruments extruded similar amounts of bacteria. Conclusions: All glide-path establishment instrument systems tested caused a measurable apical extrusion of bacteria. The manual glide-path preparation showed the highest number of bacteria extruded compared to the other NiTi glide-path establishing instruments.

• Imaging Science in Dentistry
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• 제42권1호
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• pp.19-24
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• 2012

Purpose : Field of view and voxel resolution of cone beam computed tomography (CBCT) might affect the diagnostic capability. This study was performed to compare between the standard and HiRes zoom modes in the diagnosis of external root resorption (ERR) using CBCT. Materials and Methods : Sixty three small cavities (0.25 mm depth and 0.5 mm diameter) were simulated on the buccal, lingual, and proximal surfaces at three different levels of 16 roots of teeth. After covering the root with nail varnish, the roots were inserted in the sockets and the model was placed in a water-containing lacuna. CBCT scans were taken in both standard and HiRes zoom modes using NewTom VG (QR srl Company, Verona, Italy). Then, an observer assessed the images to determine the presence or absence of the cavities. This process was repeated by increasing the size and depth of cavities to 0.5 mm depth and 1 mm diameter. Data were analyzed by McNemar test. The sensitivity, specificity, positive predictive value, negative predictive value, and likelihood ratio in evaluation of the simulated cavities were calculated. Results : There was a significant difference between the two imaging modes in diagnosing the shallow cavities (p=0.02).The sensitivity of the standard zoom in detecting the shallow cavities was lower than that of the HiRes zoom. The likelihood ratio of the HiRes zoom was higher in the diagnosis of both cavity types. Conclusion : This study suggested that a smaller voxel size in the HiRes zoom mode of CBCT is preferred for diagnosis of ERR.

• Asian Pacific Journal of Cancer Prevention
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• 제14권4호
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• pp.2503-2508
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• 2013

Histone deacetylation mediated by histone deacetylases (HDACs) has been reported as one of the epigenetic mechanisms associated with tumorigenesis. The poor responsiveness of anticancer drugs found with cholangiocarcinoma (CCA) leads to short survival rate. We aimed to investigate mRNA expression of HDACs class I and II, and the effect of HDAC inhibitors, suberoylanilide hydroxamic acid (SAHA) and valproic acid (VPA), in CCA in vitro. Expression of HDACs was studied in CCA cell lines (M213, M214 and KKU-100) and an immortal cholangiocyte (MMNK1) by semi-quantitative reverse transcription-PCR. SAHA and VPA, as well as a classical chemotherapeutic drug 5 -fluorouacil (5-FU) were used in this study. Cell proliferation was determined by sulforhodamine assay. $IC_{50}$ and $IC_{20}$ were then analyzed for each agent and cell line. Moreover, synergistic potentional of VPA or SAHA in combination with 5-FU at sub toxic does ($IC_{20}$) of each agent was also evaluated. Statistic difference of HDACs expression or cell proliferation in each experimental condition was analyzed by Student's t-test. The result demonstrated that HDACs were expressed in all studied cell types. Both SAHA and VPA inhibited cell proliferation in a dose-dependent manner. Interestingly, KKU-100 which was less senstitive to classical chemotheraoeutic 5-FU was highly was sensitive to HDAC inhibitors. Simultaneous combination of subtoxic doses of HDAC inhibitors and 5-FU signiicantly inhibited cell proliferation in CCA cell lines compared to single sgent treatment($P{\leq}0.01$), while sequentially combined treatments were less effective. The present study showed inhibitory effects of HDACIs on cell proliferation in CCA cell lines, with synergistic antitumor potential demonstrated by simultaneous combination of VPA or SAHA with 5-FU, suggesting a novel alternative therapeutic strategy in effective treatment of CCA.

• Bulletin of the Korean Chemical Society
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• 제33권11호
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• pp.3671-3675
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• 2012

${\beta}$-Amyloid accumulation in the brain is a pathological hallmark of Alzheimer's disease (AD). Since early detection of ${\beta}$-amyloid may facilitate more successful and timely therapeutic interventions, many investigators have focused on developing AD diagnostic reagents that can penetrate the blood-brain barrier (BBB). Oleanolic acid (OA) is a substance found in a variety of plants that has been reported to prevent the progression of AD in mice. In this study, we synthesized and evaluated a new radioligand in which OA was conjugated to lactoferrin (Lf, an iron-binding glycoprotein that crosses the BBB) for the diagnosis of AD. In an in vitro study in which OA-Lf was incubated with ${\beta}$-amyloid (1-42) aggregates for 24 h, we found that OA-Lf effectively inhibited ${\beta}$-amyloid aggregation and fibril formation. In vivo studies demonstrated that $^{123}I$-OA-Lf brain uptake was higher than$^{123}I$-Lf uptake. Therefore, radiolabeled OA-Lf may have diagnostic potential for ${\beta}$-amyloid imaging.