• Toxicological Research
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• v.29 no.1
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• pp.21-25
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• 2013

The selective targeting of an integrin ${\alpha}_v{\beta}_3$ receptor using radioligands may enable the assessment of angiogenesis and integrin ${\alpha}_v{\beta}_3$ receptor status in tumors. The aim of this research was to label a peptidomimetic integrin ${\alpha}_v{\beta}_3$ antagonist (PIA) with $^{99m}Tc(CO)_3$ and to test its receptor targeting properties in nude mice bearing receptor-positive tumors. PIA was reacted with tris-succinimidyl aminotriacetate (TSAT) (20 mM) as a PIA per TSAT. The product, PIA-aminodiacetic acid (ADA), was radiolabeled with $[^{99m}Tc(CO)_3(H_2O)_3]^{+1}$, and purified sequentially on a Sep-Pak C-18 cartridge followed by a Sep-Pak QMA anion exchange cartridge. Using gradient C-18 reverse-phase HPLC, the radiochemical purity of $^{99m}Tc(CO)_3$-ADA-PIA (retention time, 10.5 min) was confirmed to be > 95%. Biodistribution analysis was performed in nude mice (n = 5 per time point) bearing receptor-positive M21 human melanoma xenografts. The mice were administered $^{99m}Tc(CO)_3$-ADA-PIA intravenously. The animals were euthanized at 0.33, 1, and 2 hr after injection for the biodistribution study. A separate group of mice were also co-injected with 200 ${\mu}g$ of PIA and euthanized at 1 hr to quantify tumor uptake. $^{99m}Tc(CO)_3$-ADA-PIA was stable in phosphate buffer for 21 hr, but at 3 and 6 hr, 7.9 and 11.5% of the radioactivity was lost as histidine, respectively. In tumor bearing mice, $^{99m}Tc(CO)_3$-ADA-PIA accumulated rapidly in a receptor-positive tumor with a peak uptake at 20 min, and rapid clearance from blood occurring primarily through the hepatobiliary system. At 20 min, the tumor-to-blood ratio was 1.8. At 1 hr, the tumor uptake was 0.47% injected dose (ID)/g, but decreased to 0.12% ID/g when co-injected with an excess amount of PIA, indicating that accumulation was receptor mediated. These results demonstrate successful $^{99m}TC$ labeling of a peptidomimetic integrin antagonist that accumulated in a tumor via receptor-specific binding. However, tumor uptake was very low because of low blood concentrations that likely resulted from rapid uptake of the agent into the hepatobiliary system. This study suggests that for $^{99m}Tc(CO)_3$-ADA-PIA to be useful as a tumor detection agent, it will be necessary to improve receptor binding affinity and increase the hydrophilicity of the product to minimize rapid hepatobiliary uptake.

• Korean Journal of Food Science and Technology
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• v.42 no.5
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• pp.593-597
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• 2010

This study investigated the properties and antioxidative activities of phenolic acid concentrates of rice bran. Rice bran contains bioactive substances such as phenolic compounds, which can provide health benefits as natural antioxidants. This study examined how levels of phenolic acids can be obtained efficiently through various extraction methods. The extractions of defatted rice bran were followed by using ethylacetate (RBE-I), ethylacetate after alkaline hydrolysis (RBE-II), and 80% methanol (RBE-III). For all extracts, yields (%), total polyphenol contents (TPC), various phenolic acids and antioxidative activities were estimated. RBE-II had the highest total polyphenol contents (526.72 mg/100 g rice bran) and showed high antioxidative activity (74.7%). To concentrate the phenolic acids, RBE-II was passed through Sep-pak $C_{18}$ Vac cartridge and F1-RBE-II was collected by the elution of 50% methanol. The total phenolic content of F1-RBE-II (736.8 mg/100 g rice bran) was higher than that of RBE-II (367.1 mg/100 g rice bran), and the ratios of ferulic acid (73%) and sinapic acid (14%) increased. As RBE-II was analysed by HPLC, 6 different phenolic acids were found via chromatography, whereas F1-RBE-II showed 5 different peaks and the major phenolic acid was identified as ferulic acid. The ABTS radical scavenging activity of F1-RBE-II was the highest among the rice bran extracts. In a ${\beta}$-carotene-linoleic acid model system, linoleic acid oxidation was reduced by F1-RBE-II (73%) and RBE-II (35%).

• Journal of the Korean Chemical Society
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• v.43 no.4
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• pp.438-446
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• 1999

The optimum analytical method of aldehydes, ozone by-products, was established by reverse phase liquid chromatography. Six aldehydes including formaldehyde, acetaldehyde, acrolein, propionaldehyde, butylaldehyde and benzaldehyde, and one ketone including acetone were selected as aldehyde test samples through preliminary experiments. Such analytical conditions as the pH of citrate buffer solution, reaction temperature, reaction time, and concentration of DNPH, the component and composition of desorption solvent were optimized. As the result, pH 3.0 of citrate buffer solution, 40$^{\circ}C$ of reaction temperature, 15 minutes of reaction time, and 0.012% of DNPH concentration were chosen as optimum conditions. Aldehydes-DNPH derivatives in water were concentrated on $C_18$ Sep-Pak cartridge and followed by elution of their derivatives fraction with THF/ACN(70/30) mixture, and showed recoveries of the range from 87 to 107%. Separation condition on Nova-Pak $C_18$ column with low pressure gradient elution from ACN/MeOH/water(30/10/60) of an initial condition to 80% ACN of a final condition was found to give a good resolution within 20 minutes of run time. 86% to 103% of recovery for aldehydes using this method was similar to that for aldehyde using EPA Method 554 which is ranged from 84% to 103%.

• Archives of Pharmacal Research
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• v.10 no.1
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• pp.60-66
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• 1987

A procedure utilizing high pressure liquid chroatography coupled with UV detection is described for the determination of blood concentration of higenamine. Deproteinized serum was pretreated with$C_{18}$(Sep-pak $C_{18}$ cartridge) and the 70% EtOH eluent was applied onto a reversed-phase column ($\mu$ Bondapak $C_{18}]$) with a 15% acetonitrile in 0.05 N $NaH_2$$PO_4$-trichloroacetic acid mixed buffer (pH 2.8) as a mobile phase. With the UV detection at 232 nm, the retention times of higenamine and 1, 2, 3, 4-tetrahydropapaveroline, an internal standard, were 5.2 min and 3.9 min respectively. The blood concentration of higenamine was meausred at regular intervals after i. v. injection of higenamine to rabbit. A drastic decrease in higenamine concentration to 30% of the maximum value obtained immediately after the injection, was observed during the first 1-2 min period and thereafter the rate of decrease was slowed down. The analytical result seemed to coincide with the pharmacological effect of higenamine exerting the maximum chronotropic and hypotensive effect at the completion of the injections which were progressively recovered.

• Journal of Ginseng Research
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• v.21 no.3
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• pp.196-200
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• 1997

The headspace volatiles of the Korean ginseng and the Chinese ginseng were extracted using the SepPak Cl8 cartridge (Wasters Co.) and were analyzed using GC/MSD. The overall GC pattern of the headspace volatiles of the Chinese ginseng was similar to that of the Korean ginseng, but the composition ratios of the two major components, $\beta$-panasinsene to $\beta$-muurolene, were quite different between them. The composition ratios of $\beta$-panasinsene to $\beta$-muurolene of the Korean red and white ginseng were 1.02$\pm$0.28 (n=19) and 1.49$\pm$0.55 (n=14) , respectively. However the com- position ratios of the Chinese red and dried ginseng were 0.58$\pm$0.19 (n=41) and 0.57$\pm$0.17 (n=28), repetitively, which were significantly lower than those of the Korean ginseng at I% level. The composition ratio of the two major headspace volatile components, $\beta$-panasinsene to ${\gamma}$-muurolene, is thought to be as a useful indicator for differentiating the Chinese ginseng with the Korean ginseng.

• Analytical Science and Technology
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• v.10 no.3
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• pp.168-178
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• 1997

The optimum conditions for the residual analysis of the ethalfluralin herbicide on soils were investigated and the residues in soils were determined by gas chromatography with electron capture detector(GC-ECD). The soil samples extracted with methanol and dichloromethane and concentrated. The concentrated phase were redissolved with toluene and analyzed with GC-ECD after separated by cyanosilica gel Sep-Pak cartridge. From the standard addition experiments with 0.1 and 1.0ppm, the average recoveries were 92.8~101.2% and the detection limit was 0.004ppm. The half-life time of ethalfluralin in the soil(A) was 35 days in the laboratory and 7.2 days in the field test whereas it was 45 days and 9.7 days for each in case of soil(B).

• Journal of Food Hygiene and Safety
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• v.8 no.1
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• pp.17-23
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• 1993

In an attempt to quantitate and qualitate residual antibiotics and antibacterial agents n meat simultaneously, we studied a gas chromatogrphy-mass spectrometry (GC/MS) analysis. For a simultaneous analysis of macrolide antibiotics such as erythromycin and tylosin in meat, the homogenization with MeOH, defatting with n-hexane, extraction with CHCl3, elution with CHCl3 : MeOH=2:1 from Sep-Pak silica cartridge, acid gydrolysis, back extraction with CHCl3, and quantitation by selected ion monitoring(SIM) mode after trimethylsilyl derivatization were performed. The recoveries of erythromycin and tylosin (CV,%) at 10 ppm fortification level were 90.59(4.89) and 45.91(0.20) , and the detection limits of those were 0.02 and 2.0 $\mu\textrm{g}$/g beef, respectively. From these results, the developed analytical method using GC/MS-SIM mode allows excellent detection and quantitation of residual macrolide antibiotics in meats, using complementary method with bio-assay.

• Food Science of Animal Resources
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• v.29 no.4
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• pp.482-486
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• 2009

The aim of this study was to optimize a simple, fast, and economical analysis procedure for the determination of 16 different pesticides in raw milk via GC/MSD. Analyses were performed via gas chromatography with electron impact mass spectrometric detection in the selected ion monitoring mode (GC/MSD-SIM) using Pentachloronitrobenzene as the internal standard. The modified sample preparation methodology was based on the Pesticide Analytical Manual (PAM) of the FDA concerning fat extraction, ACN-ether partitioning, and clean-up of the Sep-Pak florisil cartridge. The modified methodology for the determination of the 16 pesticides was validated. The range of LOQs of the 16 pesticides was likely three times lower than their Maximum Residence Levels (MRLs). The recoveries of most of the pesticides were acceptable at the fortification levels of 0.5 and 1.0 ${\mu}g/mL$ and their RSD (%) level was less than 20%. None of the 16 pesticides were detected in the selected raw milk samples.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.623-625
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• 2000

Bacteriocin-producing lactic acid bacteria was isolated from Kimchi using MRS as selective media and Lactobacillus delbruekii subsp. delbruekii as an indicator strain. Strain JC-3 was tentatively identified as Lactococcus latis subsp. lactis through the API test and the bacteriocin produced by JC-3 showed the inhibitory activity against Grampositive pathogens and other lactic acid bacteria. The antimicrobial substance was inactivated by Protamax, Aroase AP-10, Neutrase, R-AMANO and was confirmed to be heating at $100^{\circ}C$. However, it was lost at high pH values showed the highest bacteriocin activity at a culture temperature of $30^{\circ}C$. The bacteriocin was partially purified by ammonium sulfate precipitation, Sep-pak $C_{18}$ cartridge. The apparent molecular mass of the bacteriocin was about 8 Kda, which was determined through the direct detection of bactericidal activity using SDS -PAGE.

• Archives of Pharmacal Research
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• v.26 no.5
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• pp.416-420
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• 2003

The analytical method of antispasmodic agent tiropramide {$(\pm)\alpha$-(benzoylamino)-4-[2-(diethylamino)ethoxy]-N,N-dipropylbenzenepropanamide hydrochloride} was developed by gas chromatography/nitrogen-phosphorus detector (GC/NPD) in human plasma. Two kinds of tiropramide tablets were orally administered to volunteers by Latin square crossover design, and blood was withdrawn as designed schedule. The plasma of 1 mL was loaded on Sep-pak $C_{18}$ cartridge and eluted with methanol after washing with 30% methanol. The residue dissolved in 100 $\mu$L of methanol after evaporation was analyzed by GC/NPD. Precision (CV%) of intra-day was located within 2.6% and accuracy was less than 9.7%. Inter-day precision was below 8.7% and accuracy was relatively good as less than 14%. Plasma samples obtained from human volunteers were analyzed for the determination of tiropramide concentration by using this method. The method was sensitive, rapid and suitable enough to be applied for pharmacokinetic and bioequivalence studies of tiropramide in human volunteers.