• Journal of radiological science and technology
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• v.38 no.3
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• pp.253-259
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• 2015

The information of contrast media concentration on target organ is very important to get reduce the side effect and high contrast imaging. We investigated alternation of signal intensity as a function of the modality of Gd-based contrast media on spin echo and ultra short time echo (UTE) of T1 effective pulse sequence at 3T MRI unit. Gadoxetic acid, which is a MRI T1 contrast medium, was used to manufacture an agarose phantom diluted in various molarities, and sterile water and agarose 2% were used as the buffer solution for the dilution. The gold standard T1 calculation was based on coronal single section imaging of the phantom mid-point with 2D Inversion recovery spine-echo pulse sequence MR imaging for testing of phantom accuracy. The 1-2mmol/L and 7mmol/L was shown the maximum signal intensity on spin echo and UTE respectively. We confirm the difference of contrast media concentration which was shown the maximum signal intensity depending on the T1 effective pulse sequence.

• Development and Reproduction
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• v.2 no.2
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• pp.149-155
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• 1998

The polysialic acid (polySia) glycotope covalently modifies cell surface glycoconjugates on cells as evolutionarily diverse as microbes and human. The recent chemical identification of polysialylated glycoproteins in the jelly coat and on the cell surface of the sea urchin egg raises important questions about their biosynthesis and possible function. Using CMP-[$^{14}$ C]Neu5Ac as substrate and cell free preparations from eggs and embryos of the sea urchin Stronglylcentrotus nudus, we have identified a membrane associated CMP-Neu5Ac:poly-$\alpha$2, 8 sialosyl sialyltransferase (polyST) that transfers Neu5Ac to an endogenous acceptor. Optimal conditions for the polyST activity were found to be 2$0^{\circ}C$ in 20 mM MOPS buffer (pH 7.0). The polyST activity was increased 2.7 times by the addition of 10 mM $Mg^2$$^{+}$. The membrane-associated polyST also catalyzed the polysialylation of mammalian ganglioside GD3. Given that no structurally similar natural polysialylated gangliosides have been described, nor were observed in the present study, we conclude that a single polyST activity catalyzes sialylation of the endogenous acceptor and the gangliosides. Using an excess of GD3 as an exogenous acceptor, it was established that the expression of the polyST in S. nudus embryos increased rapidly at the mesenchyme blastula stage and reached at maximum at the gastrula stage. The finding that this polyST in the sea urchin embryo is developmentally regulated raises the possibility that it may play a role in the changing cell and tissue interactions that occur during gastrulation and the early stages of spicule formation.n.

• Korean Journal of Microbiology
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• v.43 no.1
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• pp.19-22
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• 2007

Acetohydroxyacid synthase (E.C.2.2.1.6., AHAS) is the enzyme that catalyses the first step in the synthesis of the branched-chain amino acids valine, leucine and isoleucine. The AHAS gene (TIGR access code HI2585) from Heamophilus influenzae was cloned into the bacterial expression vector pET-28a and expressed in the Escherichia coli strain BL21(DE3). The expressed enzyme was purified by $Ni^{2+}-charged$ HiTrap chelating HP column. The purified enzyme appears as a single band on SDS-PAGE with a molecular mass of about 63.9 kDa. The enzyme exhibits absolute dependence on the three cofactors FAD, $MgCl_{2}$ and thiamine diphosphate for activity. Specific activity of purified enzyme has 3.22 unit/mg and optimum activity in the pH 7.5 at $37^{\circ}C$. This enzyme activity has an effect on the buffer. When comparing the enzyme activity against the organic solvent, it followed in type and the difference it is but even from the aqueous solution where the organic solvent is included with the fact that the enzyme activity is maintained.

• Journal of the Mineralogical Society of Korea
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• v.16 no.1
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• pp.1-17
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• 2003

The chemical composition of the arsenopyrite Ib adjoining“triple mutual contact”arsenopyrite + pyrite + hexagonal pyrrhotite may serve as a useful geothermometer in Stage II. In this study it corresponds to temperature T=33$0^{\circ}C$ and f( $S_2$)=10$^{-9.5}$ atm. And the pyrite-hexagonal pyrrhotite buffer curve indicates the probable range of the two variables; T= 315∼345$^{\circ}C$, and f( $S_2$)=10$^{-1}$0.5/∼10$^{-9}$ atm. The present antimony-bearing arsenopyrite (arsenopyrite Ic) is characterized by relatively high content of antimony, ranging from 4.95 to 8.91 percent Sb by weight and excess of iron and deficiency of anions are evident. Such a high antimonian arsenopyrite has never been known within single grain. But being the high content of antimony as in the arsenopyrite Ic, it does not serve as a geothermometer. The results of microprobe analyses for four pairs of asenopyrite and sphalerite in Stage III indicate the temperature range from 310 to 34$0^{\circ}C$, and sulphur fugacity range from 10$^{-10}$ ∼10$^{-9}$ atm. These values seem to correspond with those inferred from the Fe-As-S system.m..

• Journal of Pharmaceutical Investigation
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• v.39 no.1
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• pp.73-78
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• 2009

A simple LC-MS/MS method of rabeprazole in human plasma was developed and validated. Rabeprazole and Internal standard (I.S), omeprazole, were extracted from human plasma by liquid liquid extraction, chromatographic separation of rabaprazole in plasma was achieved at $45^{\circ}C$ with a Shiseido UG120 $C_{18}$ column and methanol-10 mM ammonium acetate buffer (pH 9.42 with ammonium water), as mobile phase. Rabeprazole produced a protonated precursor ion [$(M+H)^+$] at m/z 360.10 and corresponding product ion at m/z 242.21. Internal standard produced a protonated precursor ion [$(M+H)^+$] at 346.09 and corresponding product ion at m/z 198.09. This method showed linear response over the concentration range of $1{\sim}500\;ng/mL$ with correalation coefficient greater than 0.99. The lower limit of quantitation (LLOQ) using 0.2 mL plasma was 1 ng/mL, which was sensitive enough for pharmacokinetics studies. The method was specific and validated with a limit of quantitation of 1 ng/mL. The intra-day and inter-day precision and accuracy were acceptable for all samples including the LLOQ. The applicability of the method was demonstrated by analysis of plasma after administration of a single 10 mg dose to 36 healthy subject. From the plasma rabeprazole concentration versus time curves, the mean $AUC_t$ (The area under the plasma concentration-time curve from time 0 to 12 hr ) was $691.36{\pm}321.88\;ng{\cdot}hr/mL$, $C_{max}$ (maximum plasma drug concentration) of $353.21{\pm}131.52\;ng/mL$ reached $3.4{\pm}1.1\;hr$ after adiministration. The mean biological half-life of rabeprazole was $1.37{\pm}0.75\;hr$. Based on the results, this simple method could readily be used in pharmacokinetics studies.

• Journal of Korean Physical Therapy Science
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• v.8 no.2
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• pp.1033-1038
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• 2001

This studies were to investigate the effects of low power Helium-Neon Infra-Red(He-Ne IR) laser on the changes of the chemical components in serum of the peripheral neuropathy in diabetic rats. The twenty one Spraque-Dawley adult male rats were assigned to the 3 groups: the control group(N=7), the diabetic group(n=7) and the laser group(n=7). The diabetic group was induced with a single intravenous injecion of 50mg/kg body weight streptozotocin dissolved to 0.01mol/L citrate buffer, pH 4.5. The experimental1asser group was irradiated low power He-Ne IR laser for 5 minutes every day during 21 days to the diabetic group. The results were as follows: 1. ALT was increased the laser treatment group than the diabetic group. but that was not significant. 2. AST was significantly increased the laser treatment group than the control group and the diabetic group. 3. LDH was significantly decreased the diabetic group and laser treatment group. 4. ALP was significantly increased the diabetic group and laser treatment group. 5. CHOL was significantly decreased the laser treatment group than the diabetic group. 6. TRIG was significantly increased the laser treatment group than the diabetic group. 7. CPK was significantly increased the laser treatment group than the control group and the diabetic group.

• Journal of Pharmaceutical Investigation
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• v.32 no.3
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• pp.185-190
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• 2002

To improve the solubility of poorly water-soluble drug and to develop a sustained release tablets, the need for the technique, the formation of solid dispersion with polymeric materials that can potentially enhance the dissolution rate and extent of drug absorption was considered in this study. The 1:1, 1:4, and 1:5 solid dispersions were prepared by spray drying method using PVP K30, ethanol and methylene chloride. The dissolution test was carried out at in phosphate buffer solution at $37^{\circ}C$ in 100 rpm. Solid dispersed drugs were examined using differential scanning calorimetry and scanning electron microscopy, wherein it was found that felodipine is amorphous in the PVP K30 solid dispersion. Felodifine SR tablets were prepared by direct compressing the powder mixture composed of solid dispersed felodipine, lactose, Eudragit and magnesium stearate using a single punch press. In order to develop a sustained-release preparation containing solid dispersed felodipine, a comparative dissolution study was done using commercially existing product as control. The dissolution rate of intact felodipine, solid dispersed felodipine and its physical mixture, respectively, were compared by the dissolution rates for 30 minutes. The dissolution rates of felodipine for 30 minutes from 1:1, 1:4, 1:5 PVP K30 solid dispersion were 70%, 78% and 90%. However, dissolution rate offelodipine from the physical mixture was 5% of drug for 30 minutes. Our developed product Felodipine SR Tablet showed dissolution of 17%, 50% and 89% for 1, 4, and 7 hours. This designed oral delivery system is easy to manufacture, and drug releases behavior is highly reproducible and offers advantages over the existing commercial product. The dissolution rate of felodipine was significantly enhanced, following the formation of solid dispersion. The solid dispersion technique with water-soluble polymer could be used to develop a solid dispersed felodipine SR tablet.

• Journal of Pharmaceutical Investigation
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• v.35 no.3
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• pp.193-199
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• 2005

Gabapentin is an antiepileptic drug that is structurally similar to ${\gamma}-aminobutyric$ acid (GABA), but does not interact with the GABA receptor. It does not bind significantly to plasma proteins, and is excreted to unchanged form in the urine. The purpose of the present study was to evaluate the bioequivalence of two gabapentin capsules, $Neurontin^{TM}$ capsule 300 mg (Pfizer Pharm. Co., Ltd.) and Kuhnil $Gabapentin^{TM}$ capsule 300 mg (Kuhnil Pharm. Co., Ltd), according to the guidelines of the Korea Food and Drug Administration (KFDA). The release of gabapentin from the two gabapentin formulations in vitro was tested using KP VIII Apparatus II method with various dissolution media (pH 1.2, 4.0, 6.8 buffer solution and water). Twenty six healthy male subjects, $22.46{\pm}1.86$ years in age and $67.64{\pm}7.24$ kg in body weight, were divided into two groups and a randomized $2{\times}2$ cross-over study was employed. After a single capsule containing 300 mg as gabapentin was orally administered, blood samples were taken at predetermined time intervals and the concentrations of gabapentin in serum were determined using HPLC with fluorescence detector. The dissolution profiles of two formulations were similar at all dissolution media. In addition, the pharmacokinetic parameters such as $AUC_t$, $C_{max}$ and $T_{max}$ were calculated and ANOVA test was utilized for the statistical analysis of the parameters using logarithmically transformed $AUC_t$, $C_{max}$ and untransformed $T_{max}$. The results showed that the differences between two formulations based on the reference drug, $Neurontin^{TM}$ capsule 300 mg, were -2.03, -0.43 and 4.29% for $AUC_t$, $C_{max}$ and $T_{max}$, respectively. There were no sequence effects between two formulations in these parameters. The 90% confidence intervals using logarithmically transformed data were within the acceptance range of log 0.8 to log 1.25 $(e.g.,\;log\;0.89{\sim}log\;1.09\;and\;log\;0.91{\sim}log\;1.09$ for $AUC_t$ and $C_{max}$, respectively). Thus, the criteria of the KFDA bioequivalence guideline were satisfied, indicating Kuhnil $Gabapentin^{TM}$ capsule 300 mg was bioequivalent to $Neurontin^{TM}$ capsule 300 mg.

• Journal of Broadcast Engineering
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• v.3 no.1
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• pp.69-84
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• 1998

In digital broadcasting, services such as digital satellite TV, cable TV and digital terrestrial TV, several video programs are compressed by MPEG-2, and then simultaneously transmitted over a conventional CBR (Constant Bit Rate) broadcasting channel. In this paper, we propose a joint quality control scheme to be able to accurately control the relative picture quality among the video programs, which is achieved by simdt;,nL'Ously controlling the video encoders to generate the VBR (Variable Bit Rate) compressed video streams. Our quality control scheme can prevent the video buffer overflow and underflow by total target bit allocation process, and also exactly control the relative picture quality in terms of PSNR (Peak Signal to Noise Ratio) between some programs requiring higher picture quality and others by rate-distortion modification. Furthermore we present a rate-distortion estimation method for MPEG-2 video, which is base of our joint quality control, and verify its performance by experiments. The most attractive features of this estimation method are as follows: 1) computational complexity is low because main operation for the estimation is to calculate the histogram of OCT coefficients into quantizer; 2) estimation results are very accurate enough to be applied to the practical MPEG-2 video coding applications. Simulation results show that the proposed joint quality control scheme accurately controls the relative picture quality among the video progran1s transmitted over a single channel as well as provides more consistent and higher picture quality than independent coding scheme that encodes each program independently.

• Clinical and Experimental Pediatrics
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• v.46 no.6
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• pp.536-540
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• 2003

Purpose : Aspiration of foreign material into the lungs can cause acute or chronic pulmonary diseases. It is difficult to detect small amounts of aspiration due to the lack of safe, sensitive and specific diagnostic tests. Recently, in animal or human studies, it has been reported that immunochemistry for lactalbumin can be used to detect the minimal aspiration. So, the authors' investigation was designed to determine whether human milk phagocytized alveolar macrophages can be detected in human milk aspirated mice. Methods : Sixty four male mice, 6-8 weeks old and 30-40 gm weighing, were used for this study. About 0.05 mL of human milk or normal saline were given intranasally once per day for 1 day or 3 days. Under anesthesia with ketamine and xylazine, the trachea of each mouse was cannulated with an 18G Jelco needle and then, each mouse's lungs were lavaged three times with 0.5 mL of phosphate buffer solution at 2, 8, 24, and 48 hours after the last milk or normal saline instillation. Cells in bronchoalveolar lavage fluid were stained with Oil Red O and immunocytochemistry for alpha-lactalbumin. Results : Immunocytochemical reactivity for alpha-lactalbumin or lipid-laden alveolar macrophages were not observed in the normal saline aspirated groups. Immunocytochemical reactivity for alpha-lactalbumin were observed in the human milk aspirated groups. They showed a peak at 8 hours and decreased markedly at 24 hours but persisted even at 48 hours after aspiration. Immunocytochemical stain positive alveolar macrophages were noted similarly in number between single and multiple aspiration groups. Conclusion : These observations suggested that alveolar macrophages for lactalbumin could be more easily detected on immunocytochemistry than Oil Red O stain, and immunocytochemistry could be used as a sensitive and specific diagnostic test for the detection of human milk aspiration.