• Journal of Radiation Protection and Research
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• v.28 no.1
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• pp.43-50
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• 2003

This study describes a practical method for interpretation of bioassay results of inhaled uranium to assess the committed effective doses both for chronic and acute intake situations. Organs in the body were represented by a series of mathematical compartments for analysis of the behavior of uranium in the body according to the gastrointestinal track model, respiratory track model and biokinetic model recommended by the ICRP. An analytical solutions of the system of balance equations among the compartments were obtained using the Birchall's algorithm, and the urinary excretion function and the lung retention function of uranium were obtained. An initial or total intakes by intake modes were calculated by applying excretion and retention functions to the urinary uranium concentration and the lung burden measured with a lung counter. The dose coefficients given in ICRP 78 are used to estimate the committed effective doses from the calculated intakes.

• Environmental Mutagens and Carcinogens
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• v.23 no.1
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• pp.30-34
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• 2003

Recent industrial society has human widely exposed to PAHs (polynuclear aromatic hydrocarbons) that are comming from the incomplete combustion of organic material as wider spread environmental contaminants. Biological activities of PAHs are not known although PAHs are considered as carcinogens. Our laboratory have been studied the effect of PAHs in the mouse liver hepa 1 cells. In this study, we examined the mouse liver hepa-l cells as a new bioassay system to evaluate bioactivity of PAHs. We have selected 13 PAHs to examine bioassay using cyp1a1-luciferase reporter gene expression system where cyp1a1 1.6 Kb 5flanking region DNA was cloned in front of luciferase reporter gene and this plasmid was transfected into hepa 1 cells transiently. This cells then used for the study to observe the effect of PAHs. We demonstrated that PAHs induced the CYP1A1 promoter and 7-ethoxyresolufin O-deethylase (EROD) activities in a concentration-dependant manner. Some of PAHs showed stronger stimulatory effect on CYP1 gene expression than TCDD. Acenaphthene, anthracene, fluorine, naphthalene, pyrene, phenanthrene, carbazole were weak responders to cyp1a1 promoter activity stimulation and EROD induction in hepa 1 cells and these chemicals seemed to respond less to EROD than cyp1a1 promoter activity. Benz(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene, chrysene, and dibenzo(a,h)anthracene showed strong response to cyp1a1 promoter activity stimulation and also EROD induction in hepa 1cells. Results of dose response study suggested that four strong responding PAHs, such as benzo(a)anthracene benzo(k)fluoranthene, chrysene, and dibenzo(a, h)anthracene might be mediated through arylhydrocarbon receptor system in hepa1 cells.

• Korean Journal of Weed Science
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• v.31 no.3
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• pp.229-239
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• 2011

This study was carried out to establish an improved bioassay system on the side of practicality, pre-emergence bioassay which is more effective in developing soil application natural herbicides. A miniaturized method which have a 50 cm2 of soil surface area and was efficient by 7 times compared to the existing soil application assay ($350cm^2$ of soil surface area) was established, in which four weed species (Echinochloa crus-galli, Digitaria sanguinalis, Aeschynomene indica, and Abutilon theophrasti) were planted and grown in greenhouse. This would be applicable when the amount of screening compound is much more than 50 mg. The initial application rate was desirable at $10,000{\mu}g\;mL^{-1}$. On the other hand, the 6 well plate assay which has 4 weed species in each well containing upland soil and could be conducted in growth chamber, was established. This assay was resulted in minimizing in level of 1/14 test volume and 1/14 amounts of test compound to the conventional method that has been used for screening of synthetic compounds in KRICT, and applicable for the small amount of test compound (less than 10 mg). Therefore, the improved bioassays established in this study would be helpful for a rapid and efficient development of soil application natural herbicides.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2004.05a
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• pp.47-60
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• 2004

Higher plants can be valuable genetic assay systems for monitoring environmental pollutants and evaluating their biological toxicity. Two assays are considered ideal for in situ monitoring and testing of soil, airborne and aqueous mutagenic agents; the Tradescantia stamen hair assay for somatic cell mutations and the Tradescantia micronucleus assay for chromosome aberrations. Both assays can be used for in vivo and in vitro testing of mutagens. Since higher plant systems are now recognized as excellent indicators and have unique advantages over in situ monitoring and screening, higher plant systems could be accepted by regulatory authorities as an alternative first-tier assay system for the detection of possible genetic damages resulting from the pollutants or chemicals used and produced by industrial sectors. It has been concluded that potential mutagen and carcinogen such as the heavy metals among indoor air particulates, volatile compounds in the working places, soil, and water pollutants contribute to the overall health risk. This contribution can be considerable under certain circumstances. It is therefore important to identify the level of genotoxic activity in the environment and to relate it to the biomarkers of a health risk in humans. The results from the higher plant bioassays could make a significant contribution to assessing the risks of pollutants and protecting the public from agents that can cause mutation and/or cancer. The plant bioassays, which are relatively inexpensive and easy to handle, are recommended for the scientists who are interested in monitoring pollutants and evaluating their environmental toxicity to living organisms.

• Microbiology and Biotechnology Letters
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• v.24 no.4
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• pp.472-477
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• 1996

Natural human epidermal growth factor (nhEGF) was purified from pregnant human urine by benzoic acid adsorption, DEAE-Sepharose ion exchange, and immunoaffinity chromatography. The purified nhEGF was further separated into four fractions using Bondapak C$_{18}$ HPLC system. Following characterization by Western blot analysis and double immu- nodiffusion, we found that each fraction corresponds to four derivatives of the nhEGF. For biological analysis of nhEGF, we optimized the labeling time and serum concentration for the incorporatioin of 5-bromo-2'-deoxy uridine (BrdU), a non-radioactive alternative for [$^{3}$H]-thymidine uptake, into NIH 3T3 cells. The DNA synthesis of NIH 3T3 cells was gradually increased at the nhEGF concentrations between 0.1 - 10 ng/ml in the Dulbecco's Modified Eagles Medium (DMEM) containing 0.2% Fetal calf serum (FCS). When we assayed the biological activity of four fractions, the activity of the second fraction was superior to that of the others. Based on the results from the HPLC analysis spiked with recombinant human epidermal growth factor (rhEGF) and amino acid sequencing, we concluded that the second fraction was nhEGF and the other three fractions were the derivatives of nhEGF. In addition, the proportion of nhEGF was approximately 46% is compared with that of the other three derivatives.

• Archives of Pharmacal Research
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• v.22 no.3
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• pp.279-287
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• 1999

Therapeutic use of anti-inflammatory steroids is limited due primarily to their systemic suppressive effects on pituitary function and the immune system.. To overcome the clinical limitation, a new approach toward the discovery of non-systemic anti-inflammatory steroids is based upon the antedrug concept introduced by this laboratory. The new concept describes locally active agents which are designed to undergo a predictable biotransformation to inactive metabolites upon entry into systemic circulation from the applied site. Thus, true antedrugs are devoid of systemic adverse effects. In a continuing effort, 16$\alpha$-carboxylate and isoxazoline derivatives of prednisolone have been synthesized and screened. In the croton oil-induced ear edema bioassay, the following relative potencies were obtained setting hydrocortisone=1.0; 3a, 1.5; 3b, 3.1; 4a, 4.0; 4b, 12.2; 5b, 8.2; 6b, 11.2; 7a, 1.9; 7b, 4.1; 8a, 3.3; 8b 6.8; 9a, 0.7; 9b 8.6; 10a 2.6; 10b, 7.4. Results of the five-day bioassay indicated that, in contrast to the parent compound, the novel steroidal antedrugs did not significantly alter body weight gain, thymus weights, adrenal weights or plasma corticosterone levels. Taken together, the antedrug concept appears to be a fundamentally sound strategy for the separation of local anti-inflammatory activity form systemic adverse effects.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2001.05a
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• pp.122-122
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• 2001

The reaction kinetics of hexavalent chromium with ferrous ions were studied to determine the influence of reduction on the toxicity of chromium to aquatic organisms. The changes in chemical forms of the chromate in the presence of ferrous ions were examined in a bioassay system using Dphnia magna as a test organism. (omitted)

• Korean Journal of Plant Resources
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• v.27 no.5
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• pp.401-414
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• 2014

In an attempt to evaluate licorice quality based on its biological activity, we grafted an on-line high-performance liquid chromatography (HPLC) bioassay method into the previously established HPLC analysis method. The common antioxidant peaks in licorices of various origin were observed through an on-line HPLC/DPPH system leading to a decrease in absorbance at 517 nm for 2,2-diphenyl-1-picrylhydrazyl (DPPH). Among them, the licorice from Youngju possessed the highest activity. Therefore, three active standard compounds from the dehydroglyasperin C, dehydroglyasperin D, and isoangustone A, were isolated and elucidated by medium pressure liquid chromatography (MPLC) and instrumental analysis such as nuclear magnetic resonance (NMR), respectively. On-line HPLC/ABTS analysis method with the simultaneous determination of three standard compounds and their radical scavenging activity was established for the quality evaluation of licorices. 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid radicals (ABTS) which is stable and effective was used in replace of DPPH. The radical scavenging activity of three standards is compared with that of Trolox, known as antioxidant, showing a negative peak with a decrease in absorbance at 734 nm for ABTS. This on-line HPLC/ABTS analysis method was validated for specificity, linearity, precision and accuracy in compliance with international conference on harmonization (ICH) guideline.

• Korean Chemical Engineering Research
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• v.48 no.5
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• pp.545-555
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• 2010

Recently, droplet-based microfluidic systems are widely used in various areas ranging from fundamental science including chemistry, biology, and physics to material science and engineering. This article reviews recent development in the droplet based microfluidic system from basic fabrication of tiny device, principle of droplet formation, merging, mixing, control of droplets, and application for the synthesis of novel functional materials. We discuss strong advantages of the droplet based microfluidics in point of control of particle size, morphologies, shapes, and structures.

• Applied Biological Chemistry
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• v.29 no.1
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• pp.22-28
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• 1986

To establish the bioassay system not only for brassinosteroids and auxins but also for growth retardants with the lamina joints of rice, excellent domestic cultivars were selected and affectable factors, condition of test material, pH, temperature, concentration of test solution, coexisting metallic ions ana combination with growth regulators, on the assay system were discussed.