• Polymer(Korea)
• /
• v.31 no.6
• /
• pp.505-511
• /
• 2007

Poly(lactide-co-glycolide)(PLGA) and hyaluronic acid (HA) has been widely used as biocompatible scaffold materials to regenerate tissue. In this present study, we fabricated microporous PLGA and HA loaded PLGA scaffolds by a emusion freeze-drying method. In order to confirm that the release profile of cytokine or water-soluble drugs, we manufactured the granulocyte macrophage colony stimulating factor(GM-CSF) loaded PLGA and HA-PLGA scaffold. All scaffolds were characterized using scanning electron microscope(SEM), mercury porosimeter and wettability measurement. Cell proliferation and viability were assessed by a 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium-bromide (MTT) test. The porosity of HA-PLGA scaffold was greater than 95% with the total pore area of $261\;m^2/g$. The HA-FLGA scaffold exhibited well interconnected pores to allow greater cell adhesion and prolixferation. It was proven by higher cell viability in the HA-PLGA scaffold than PLGA alone. This may be due to the enhanced natural properties and higher water retention capacity of HA.

• Korean Journal of Agricultural Science
• /
• v.25 no.1
• /
• pp.131-137
• /
• 1998

The cellulase components were partially purified from the culture filtrate of the alkalophilic bacterium Pseudomonas sp. AC-711 and its enzymatic properties were characterized. The specific activity of the purified major enzyme component was 3.5 units/mg protein as carboxymethyl cellulase and the yield was 23% of the total activity of the culture broth. The molecular weight of the component was 46,000 and the Km and Vmax on CMC were determined as $15.4mg\;mL^{-1}$ and $4.17{\mu}moles\;mL^{-1}\;min^{-1}$, respectively. The enzyme was stable at the temperatures below $60^{\circ}C$ and at the pH range of 4.0~11.0, and the optimal temperature and pH were $60^{\circ}C$ and pH 8.0, respectively. The enzyme activity was not significantly affected by the common surfactants (concentration: 0.05%) such as ${\alpha}$-olefin sulfonate, linear alkylbenzene sulfonate, sodium dodecyl sulfonate, hexadecyltrimethylammonium bromide and Tween 80. The enzyme was activated by the metal ions such as $Ca^{2+}$, $Cu^{2+}$, $Co^{2+}$, whereas inhibited by $Hg^{2+}$ and $Zn^{2+}$. The enzyme exhibited relatively high activity toward amorphous CMC as compared with crystalline substrates such as filter paper and avicel.

• Parasites, Hosts and Diseases
• /
• v.29 no.2
• /
• pp.129-138
• /
• 1991

Tetrahymena pyriformis is a free-living ciliate protozoan in the freshwater system. Experiments were carried out to determine whether intraperitoneal administration of T. pyriformis (GL strain) to mice activates macrophages to be able to kill Toxoplasma gondii tachyzoites in vitro. Mice were also injected intraperitoneally with several synthetic activators; dimethyldioctadecylammonium bromide (DDA), dextran sulfate, complete Freund's adjutant (CFA) as well as Toxoplasma and Tetrehymena Iysates in order to activate mouse peritoneal macrophages. One week after the administration of activators, peritoneal cells were harvested and the adherent macrophages were challenged with Toxoplasma tachyzoites. Macrophage monolayers were then fixed with absolute methanol after washing, and stained with Giemsa solution. The percentage of the adherent cells infected and total number of organisms per 100 macrophages were calculated to make toxoplasma-cidal activity of macrophages according to the cultivation time. Peritoneal macrophages from mice administered with Tetrahymena exhibited significant protection against target parasites as compared with those treated with synthetic activators. Among non-biological synthetic activators, DDA was evaluated as an ellcellent activator.

• Applied Biological Chemistry
• /
• v.35 no.4
• /
• pp.308-314
• /
• 1992

To examine the characteristics of anti-complementary compounds from Arecae Pericarpium (the pericarps of Areca catechu) which showed the highest activity during our screening procedures, the extraction and purification were performed. AC-1 fraction from Arecae Pericarpium was purified by hot water extraction, methanol reflux, ethanol precipitation, dialysis and lyophilization. This compound had total sugar 48.2%, uronic acid 14.6% and protein 36.8%. Rhamnose, arabinose, mannose and galactose were found in sugar components. By cetavlon (cetyltrimethylammonium bromide) treatment AC-1 was fractionated to AC-2, AC-3 and AC-4. Among them, AC-2 showed the highest activity and yield. By periodate oxidation, AC-2 was deactivated, but had no change in activity by pronase digestion. Moreover active fractions, AC-2-IIIa and AC-2-IIIc isolated from AC-2 by two successive column chromatography using DEAE-Toyopearl $650C(Cl^-form)$ and Sephadex G-100. AC-2-IIIa was mainly made up of rhamnose, mannose, galactose and glucose, and AC-2-IIIc, mannose, galactose and glucose. These both polysaccharides were identified as homogeneous by gel filtration of Sepharose CL-4B and electrophoresis, and molecular weights of them were 120,000 and 15,000, respectively.

• Journal of Applied Biological Chemistry
• /
• v.63 no.1
• /
• pp.9-22
• /
• 2020

This study was designed to use the safety management data for residual pesticides in imported banana based on the investigation of pesticide residue detection of agricultural products with different origins in the Republic of Korea. From the USA, EU, UK, Japan and Korea from 2007 to 2018, the results of banana residue pesticides were summarized into detected pesticides, number of inspections, number of pesticide detection cases, and the amount of detected pesticide residue. A total of 109 pesticides were detected for the pesticide residue and pesticide detection rate was 4.58% in 206,894 cases. The detection rate was ranged within 10.62-24.62% for chlorpyrifos, imazalil, methyl-bromide, azoxystrobin, carbendazim, pretilachlor and thiabendazole. Among them, chlorpyrifos was detected most often followed by imazalil, azoxystrobin, thiabendazole, bifenthrin and carbendazim. According to the results of monitoring data for bananas in EU, Japan, USA, UK and Korea, the kinds of detected pesticides were 85, 57, 23, 18 and 8, respectively. Azoxystrobin, bifenthrin and chloropyrifos were found in monitoring data of all countries. Fourteen and twelve pesticides were detected in bananas from Costa Rica and Ecuador, respectively. Imazalil and thiabendazole were detected in 16 and 11 origins, respectively. Myclobutanil and iprodione were detected in four and two countries, respectively. In bananas from Costa Rica, azoxystrobin and bifenthrin were detected 11.8 and 9.8%, respectively, and the detection rate of azoxystrobin was 19% in bananas from Colombia. Chlorpyrifos was detected 22.7, 13.3 and 10.8% in bananas from Belize, Colombia and Costa Rica respectively. Myclobutanil was detected in bananas from Colombia and Costa Rica with the rate of 17.9 and 10.4%, respectively.

• Fire Science and Engineering
• /
• v.23 no.5
• /
• pp.24-31
• /
• 2009

Based on fallen leaves of major Korean conifer species 'Pinus densiflora' and major Korean broadleaved species 'Quercus variabilis', this study sought to identify combustion emission gas types and measure their concentration by means of FTIR (Fourier Transform Infrared) spectrometer. As a result, it was found that there were total 13 types of combustion gas detected from fallen leaves of Pinus densiflora and Quercus variabilis, such as carbon monoxide, carbon dioxide, acetic acid, butyl acetate, ethylene, methane, methanol, nitrogen dioxide, ammonia, hydrogen fluoride, sulfur dioxide and hydrogen bromide. Notably, nitrogen monoxide was additionally detected from fallen leaves of Quercus variabilis. It was found that the overall concentration of combustion gas emitted from the fallen leaves of Pinus densiflora was 4.5 times higher than that from fallen leaves of Quercus variabilis. Particularly, it was found that emission concentration of some combustion emission gas types like carbon monoxide, carbon dioxide and butyl acetate exceeded the upper limit of their time-weighted average (TWA, ppm), while the emission concentration of carbon monoxide and carbon dioxide exceeded their short-term exposure limit (STEL, ppm) for both species. Thus, it was found that carbon monoxide and carbon dioxide have higher hazard to health than other gas types, because these two gas types account for higher than 99% of overall gas emission due to combustion of surface fire starting from litter layer in forest.

• Analytical Science and Technology
• /
• v.19 no.5
• /
• pp.433-440
• /
• 2006

A HPLC/UV method was developed and validated for the rapid and simultaneous determination of urinary metabolites of organic solvents, mandelic acid, hippuric acid, phenylglyoxylic acid, ortho-, meta- and para-methylhippuric acid, using a monolithic column. The mobile phase was composed of tetrabutylammonium bromide as ion-pairing reagent with a flow rate of 2.4 mL/min. The total run time was less than 2.5 min for all six analytes. Good linearities were obtained for all the metabolites with correlation coefficients above 0.9993. Intra-day precision, accuracy and inter-day precision was 0.01~7.32%, 83.9~116.3% and 0.01~7.16%, respectively. The method was validated and confirmed by quantification of the quality assurance samples of Industrial Safety and Health Research Institute, Korea Occupational Safety and Health Agency.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.58 no.1
• /
• pp.20-27
• /
• 2013

Proximate composition, total phenolics and total flavonoids level, DPPH radical scavenging activity, and cytotoxicity were determined in the methanol extracts of different plant parts of Youngia sonchifolia at reproductive growth stage. Crude protein and crude fat were present as the highest amount in flowers, and crude fiber in the stems and roots. The highest content of phenolics [mg ferulic acid equivalents (FAE) $kg^{-1}$ dry weight (DW)] was found in flowers (highest) and followed by leaves, stems and roots (lowest). Flavonoids [mg rutin equivalents $kg^{-1}$ DW] level, however, showed the highest in leaf extracts and lowest in root extracts. The antioxidant potential of the methanol extracts from the plants dose-dependently increased DPPH (1,1-diphenyl-2-picrylhydrazyl) free radical scavenging activity (%). DPPH radical scavenging activity were highest in root extracts ($IC_{50}=1,135.6\;mg\;kg^{-1}$) and followed by leaf, stem and flower extracts. By way of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay, methanol extracts of roots showed the highest anticancer activity on human cancer cell line Calu-6 for human pulmonary carcinoma ($IC_{50}=196.3\;mg\;kg^{-1}$) and HCT-116 for human colon carcinoma ($IC_{50}=623.6\;mg\;kg^{-1}$).

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.1
• /
• pp.489-494
• /
• 2014

Background: Psychiatric patients appear to be at lower risk of cancer. Some antipsychotic drugs might have inhibitory effects on tumor growth, including penfluridol, a strong agent. To test this, we conducted a study to determine whether penfluridol exerts cytotoxic effects on tumor cells and, if so, to explore its anti-tumor mechanisms. Methods: Growth inhibition of mouse cancer cell lines by penfluridol was determined using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Cytotoxic activity was determined by clonogenic cell survival and trypan blue assays. Animal tumor models of these cancer cells were established and to evaluate penfluridol for its anti-tumor efficacy in vivo. Unesterified cholesterol in cancer cells was examined by filipin staining. Serum total cholesterol and tumor total cholesterol were detected using the cholesterol oxidase/p-aminophenazone (CHOD-PAP) method. Results: Penfluridol inhibited the proliferation of B16 melanoma (B16/F10), LL/2 lung carcinoma (LL/2), CT26 colon carcinoma (CT26) and 4T1 breast cancer (4T1) cells in vitro. In vivo penfluridol was particularly effective at inhibiting LL/2 lung tumor growth, and obviously prolonged the survival time of mice bearing LL/2 lung tumors implanted subcutaneously. Accumulated unesterified cholesterol was found in all of the cancer cells treated with penfluridol, and this effect was most evident in LL/2, 4T1 and CT26 cells. No significant difference in serum cholesterol levels was found between the normal saline-treated mice and the penfluridol-treated mice. However, a dose-dependent decrease of total cholesterol in tumor tissues was observed in penfluridol-treated mice, which was most evident in B16/F10-, LL/2-, and 4T1-tumor-bearing mice. Conclusion: Our results suggested that penfluridol is not only cytotoxic to cancer cells in vitro but can also inhibit tumor growth in vivo. Dysregulation of cholesterol homeostasis by penfluridol may be involved in its anti-tumor mechanisms.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.38 no.12
• /
• pp.1679-1684
• /
• 2009

Opuntia humifusa, widely distributed in the southern regions of the Korean peninsula, is known to have bioactive functions and medicinal benefits for treating various diseases such as arteriosclerosis, diabetes mellitus, gastritis, and hyperglycemia. In this study total polyphenol and flavonoid contents of fruit and its anticarcinogenic effects on human breast cancer were investigated. As expected, O. humifusa showed high concentrations of total polyphenol as well as flavonoid as compared to other kinds of cactus. Effects of the water extracts of O. humifusa on the proliferation, G1 arrest and apoptosis of the MCF-7 human breast cancer cells were also examined using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays, and G1 cycle arrest and apoptotic effect of O. humifusa were analyzed by flow cytometry. When MCF-7 cells were treated with different concentrations of hexane, ethyl acetate and water extracts of O. humifusa, water extracts of the fruit significantly decreased viable cell numbers in a concentration dependent manner. A G1 arrest in MCF-7 cells was induced as well. The overall results indicate that water extracts of fruit of O. humifusa would inhibit MCF-7 human breast cancer cell proliferation and induce G1 arrest.