• Journal of Life Science
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• v.26 no.2
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• pp.174-180
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• 2016

Dicumarol is a coumarin derivative isolated from sweet clover (Melilotus alba), and has anti-coagulant activity with the inhibitory activity of NAD(P)H quinone oxidoreductase1 (NQO1). NQO1 catalyzes the two-electron reduction of quinones to hydroquinones. Dicumarol competes with NAD(P)H for binding to NQO1, resulting in the inhibition of NQO1 enzymatic activity. The expression of matrix metalloproteinases (MMPs) has been implicated in the invasion and metastasis of cancer cells. The expression of MMPs is regulated by cytokines and signal transduction pathways, including those activated by phorbol myristate acetate (PMA). However, the effects of dicumarol on metalloproteinase (MMP)-9 expression and activity are not investigated here. This study investigated whether dicumarol inhibits MMP-9 expression and activity in PMA-treated human renal carcinoma Caki cells. Dicumarol markedly inhibited the PMA-induced MMP-9 mRNA expression and MMP-9 activity. NF-κB and AP1 promoter activity, which is important in MMP-9 expression, also decreased in dicumarol-treated cells. Furthermore, dicumarol markedly suppressed the ability of PMA-mediated migration in Caki cells. When the relevance of NQO1 in the dicumarol-mediated inhibitory effect on PMA-induced MMP9 activity was elucidated, knock-down of NQO1 with siRNA was found to have no effect on PMA-induced MMP9 activity, suggesting that the stimulating effect of dicumarol on PMA-induced MMP9 activity is independent of NQO1 activity. Taken together, the present studies suggested that dicumarol may inhibit PMA-induced migration via down-regulation of MMP-9 expression and activity.

• Journal of Life Science
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• v.31 no.4
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• pp.389-399
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• 2021

This study determined the effects of Centella asiatica leaf on H₂O₂ induced cell cycle arrest, mitochondrial activity, and proinflammatory cytokine production in human dermal fibroblast (HDF) cells. We used an 80% methanol extract of C. asiatica, its ethyl acetate fraction, and asiaticoside, the major constituent of C. asiatica. The C. asiatica extract, its ethyl acetate fraction, and asiaticoside attenuated G1 cell cycle-arrest and the apoptotic effect caused by H₂O₂-induced oxidative stress. The cells treated with C. asiatica extract, its ethyl acetate fraction, and asiaticoside secreted lower levels of TNF-α and IL-6. The antioxidant effect of asiaticoside was higher than that of C. asiatica extract and its ethyl acetate fraction. Treatment with C. asiatica extract, its ethyl acetate fraction, and asiaticoside also increased the mitochondrial membrane potential and restored normal mitochondrial morphology. Following H₂O₂ stress induction, cells treated with C. asiatica extract, its ethyl acetate fraction, and asiaticoside showed increased mitochondrial oxygen consumption rates and decreases in the TLR4-MyD88-TRAF6-p65 pathway activity. These findings suggest that C. asiatica extract, its ethyl acetate fraction, and asiaticoside have antioxidant and anti-inflammatory effects, as well as the ability to control the mitochondrial activities of HDF cells.

• Microbiology and Biotechnology Letters
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• v.49 no.1
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• pp.120-129
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• 2021

Rotavirus A (RVA) is recognized as a major etiology responsible for the development of acute gastroenteritis in children worldwide. The purpose of the present study was to perform the molecular characterization of RVA. A total of 323 stool specimens collected from hospitalized children with acute gastroenteritis in Chiang Rai, Thailand, in 2016-2018 were identified for G- and P-genotypes through RT-PCR analysis. RVA was more prevalent in 2017-2018 (37.8%) than in 2016-2017 (23.2%). The seasonal peak of RVA occurred from March to April. G3P[8] was predominant in 2016-2017 (90.6%) and 2017-2018 (58.6%). Other genotypes including G1P[8], G8P[8], G9P[8], and mixed infections were also identified. G3P[8] strains clustered together in the same lineage with other novel human equine-like G3P[8] strains previously identified in multiple countries and presented a genotype 2 constellation (G3-P[8]-I2-R2-C2-M2-A2-N2-T2-E2-H2). Several amino acid differences were observed in the antigenic epitopes of the VP7 and VP8* capsid proteins of the equine-like G3P[8] compared with those of the RVA vaccine strains. The homology modeling of the VP7 and VP8* capsid proteins of the equine-like G3P[8] strains evidently exhibited that these residue differences were present on the surface-exposed area of the capsid structure. The emergence of the equine-like G3P[8] strains in Thailand indicates the rapid spread of strains with human and animal gene segments. Continuous surveillance for RVA is essential to monitor genotypes and genetic diversity, which will provide useful information for selecting rotavirus strains to develop a safe and effective RVA vaccine that is efficacious against multiple genotypes and variants.

• Biomedical Science Letters
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• v.11 no.3
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• pp.327-332
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• 2005

Sf21 cells become popular as the host permissive cell line to support the baculovirus AcNPV replication and protein synthesis. The cells grow well on TC-100 medium that contains $0.1\%$ D-glucose as the major carbon source, strongly suggesting the presence of endogenous glucose transporters. However, unlike human glucose transporters, very little is known about the characteristics of the endogenoussugar transporter(s) in Sf21 cells. Thus, some kinetic properties of the sugar transport system were investigated, involving the uptake of 2-deoxy-D-glucose (2dG1c). In order to obtain a true measure of the initial rate of uptake, the uptake of $[^3H]2dGlc$ from both low $(100{\mu}M)$ and high (10 mM) extracellular concentrations was measured over periods ranging from 30 sec to30 min. The data obtained indicated that the uptake was linear for at least 2 min at both concentrations, suggesting that measurements made over a 1min time course would reflect initial rates of the jexpse uptake. To determine $K_m\;and\;V_{max}$ of the endogenous glucose transporter(s) in Sf21 cells, the uptake of 2dG1c was measured over a range of substrate concentrations $(50{\mu}M\~10mM)$ 2dG1c uptake by the Sf21 cells appeared to involve both saturable and non-saturable (or very low affinity) components. A saturable transport system for 2dG1c was relatively high, the $K_m$ value for uptake being < 0.45 mM. The $V_{max}$ value obtained for 2dG1c transport in the Sf21 cells was about 9.7-folds higher than that reported for Chinese hamster ovary cells, which contain a GLUT1 homologue. Thus, it appeared that the transport activity of the Sf21 cells was very high. In addition, the Sf21 glucose transporter was found to have very low affinity for cytochalasin B, a potent inhibitor of human erythrocyte glucose transporter

• Nutritional Sciences
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• v.9 no.2
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• pp.61-67
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• 2006

Green tea has attracted attention with respect to its potential for preventing and treating neurodegenerative disease. The neurotoxin, 6-hydroxydopamine (6-OHDA), was used to produce experimental Parkinson's disease (PD) model. The purpose of this study was to investigate the effects of green tea diet on behavioral changes, striatal dopamine content, and hepatic antioxidant parameters of PD model rats. In this study, we used male Sprague-Dawley rats weighing $200\sim220g$ and injected 6-OHDA into the right substantia nigra and medial forebrain bundle of the brain. The supply of green tea diet was started at 2 weeks before 6-OHDA lesion and continually supplied during 0, 2, and 4 weeks after 6-OHDA lesion (GT-0, GT-2, GT-4). Behavioral disturbance was measured by the stepping and d-amphetamine drug-induced rotation tests. Then, we assayed the striatal dopamine content and the hepatic malondialdehyde (MDA), hydrogen peroxide $(H_2O_2)$, and superoxide dismutase (SOD) activity. The percentage of lesioned forepaw to non-lesioned forepaw step scores was the highest in GT-4 group among all groups at both 3 and 4 weeks after 6-OHDA lesion. At 4 weeks after 6-OHDA lesion, the rotation score was the lowest in GT-2 group (p<0.05). However, increasing rate of the rotation score from 2 to 4 weeks after 6-OHDA lesion was the lowest in GT-4 group. The striatal dopamine content was not significantly different among four groups by green tea diet. The hepatic MDA level was the lowest in GT-4 group among four groups. The hepatic SOD activity was increased with the prolongation of green tea diet period These results suggest that green tea diet affects behavioral changes in rats of PD model. It seems that continuous green tea supplementation has an influence on the reduction of behavioral disturbance and the hepatic MDA level. Accordingly, continuous green tea supplementation was recommended for the prevention and treatment of PD. However, further studies are needed to investigate the mechanisms and efficacy of green tea in PD.

• Archives of Pharmacal Research
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• v.27 no.6
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• pp.662-669
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• 2004

The highly water-soluble monomethoxypoly(ethyleneglycol) (mPEG) prod rugs of cyciosporin A(CsA) were synthesized. These prod rugs were prepared by initially preparing intermediate in the form of carbonate at the 3'-positions of CsA with chloromethyl chloroformate, in the pres-ence of a base to provide a 3'-carbonated CsA intermediate. Reaction of the CsA intermediate with mPEG derivative in the presence of a base provides the desired water-soluble prod rugs. As a model, we chose molecular weight 5 kDa mPEG in the reaction with CsA to give water soluble prodrugs. To prove that the prod rug is decomposed in the body to produce CsA, the enzymatic hydrolysis test was conducted using human liver homogenate at $37^{\circ}C$. The prodrug was decomposed in human liver homogenate to produce the active material, CsA, and the hydrolysis half-life ($t_{1/2}$) of the prodrug, KI-306 was 2.2 minutes at $37^{\circ}C$. However, a demon-stration of non-enzymatic conversion in pH 7.4 phosphate buffer was provided by the fact that the half-life ($t_{1/2}$) is 21 hours at 37$^{\circ}C$. The hydrolysis test in rat whole blood was also conducted. The hydrolysis was seen with half-life ($t_{1/2}$) of about 9.9, 65.0, 14.2, 3.4, 2.1 9.5, and 1.6 minutes for KI-306, 309, 312, 313, 315, 316, and 317, respectively. This is the ideal for CsA prodrug. The pharmacokinetic study of the prodrug, KI-306, in comparison to the commer-cial product (Sandimmune Neoral Solution) was also carried out after single oral dose. Each rat received 7 mg／kg of CsA equivalent dose. Especially, the prodrug KI-306 exhibits higher AUC and $C_{max}$ than the conventional Neoral. The AUC and $C_{max}$ were increased nearly 1.5 fold. The kinetic value was also seen with $T_{max}$ of about 1.43 and 2.44 hours for KI-306 and Neoral, respectively.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.4 no.2
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• pp.65-72
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• 2018

Prostate specific membrane antigen (PSMA) is a cell surface membrane protein, which is overexpressed in most prostate cancer. Recently, PET imaging with $[^{68}Ga]$PSMA-HBED-CC has been widely used for the diagnosis of recurrent prostate cancer and the studies on the diagnostic potential of $^{64}Cu$-labeled PSMA ligands reported actively. In this study, we monitored with biological evaluation in vivo and PET imaging of $^{64}Cu$-labeled PSMA ligand ($[^{64}Cu]$PSMA-617). The radiolabelling efficiency and stability of $[^{64}Cu]$PSMA-617 were confirmed by radio-thin layer chromatography. The radiolabeling efficiency of $[^{64}Cu]$PSMA-617 showed over 95%, and stabilities of intact remained over 98% in both human and mouse serum for 48 h. In normal male mice, in vivo uptake of $[^{64}Cu]$PSMA-617 in several organs was measured at 2, 4, 6, 24, 48 h after injection. Rapid blood clearance was observed for $[^{64}Cu]$PSMA-617. The high uptake was observed in the lung, liver, intestines and kidneys at 2 h postinjection, but was low in the other organs (1-2 %ID/g) at 4 h. The dynamic PET/CT images of 22RV1 tumor-bearing nude mice were acquired during 60 min and additionally acquired 24 h and 48 h after injection. In dynamic PET images, $[^{64}Cu]$PSMA-617 uptake ratio in tumors versus muscle was increased as time elaplsed until 60 minutes and remained in tumors at 48 h. In these results, the PET/CT imaging using $[^{64}Cu]$PSMA-617 in prostate cancer is expected to be useful for the diagnosis and treatment of prostate cancer patients.

• Advanced Composite Materials
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• v.18 no.4
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• pp.351-364
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• 2009

The thermal stability and elevated temperature mechanical properties of $SiC_P$/Al-11.7Fe-1.3V-1.7Si (Al-11.7Fe-1.3V-1.7Si reinforced with SiC particulates) composites sheets prepared by spray deposition (SD) $\rightarrow$ hot pressing $\rightarrow$ rolling process were investigated. The experimental results showed that the composite possessed high ${\sigma}_b$ (elevated temperature tensile strength), for instance, ${\sigma}_b$ was 315.8 MPa, which was tested at $315^{\circ}C$, meanwhile the figure was 232.6 MPa tested at $400^{\circ}C$, and the elongations were 2.5% and 1.4%, respectively. Furthermore, the composite sheets exhibited excellent thermal stability: the hardness showed no significant decline after annealing at $550^{\circ}C$ for 200 h or at $600^{\circ}C$ for 10 h. The good elevated temperature mechanical properties and excellent thermal stability should mainly be attributed to the formation of spherical ${\alpha}-Al_{12}(Fe,\;V)_3Si$ dispersed phase particulates in the aluminum matrix. Furthermore, the addition of SiC particles into the alloy is another important factor, which the following properties are responsible for. The resultant Si of the reaction between Al matrix and SiC particles diffused into Al matrix can stabilize ${\alpha}-Al_{12}(Fe,\;V)_3Si$ dispersed phase; in addition, the interface (Si layer) improved the wettability of Al/$SiC_P$, hence, elevated the bonding between them. Furthermore, the fine $Al_4C_3$ phase also strengthened the matrix as a dispersion-strengthened phase. Meanwhile, load is transferred from Al matrix to SiC particles, which increased the cooling rate of the melt droplets and improved the solution strengthening and dispersion strengthening.

• BMB Reports
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• v.42 no.1
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• pp.22-27
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• 2009

Replication Protein A (RPA) is a single stranded DNA-binding protein involved in DNA metabolic activities such as replication, repair, and recombination. RPA-Interacting Protein $\alpha$ ($RIP{\alpha}$) was originally identified as a nuclear transporter of RPA in Xenopus. The human $RIP{\alpha}$ gene encodes several splice isoforms, of which $hRIP{\alpha}$ and $hRIP{\beta}$ are the major translation products in vivo. However, limited information is available about the alternative splicing of $RIP{\alpha}$ in eukaryotes, apart from that in humans. In this study, we examined the alternative splicing of RIP{\alpha} in the Drosophila, Xenopus, and mouse system. We showed that the number of splice isoforms of RIP{\alpha} was species-specific, and displayed a tendency to increase in higher eukaryotes. Moreover, a mouse ortholog of $hRIP{\alpha}$, $mRIP{\beta}2$, was not SUMOylated, in contrast to $hRIP{\alpha}$. Based on these results, we suggest that the $RIP{\alpha}$ gene gains more splice isoforms and additional modifications after molecular evolution.

• Mass Spectrometry Letters
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• v.12 no.4
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• pp.179-185
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• 2021

Collision-induced dissociation (CID) combined with electrospray ionization mass spectrometry (ESI-MS) was used to obtain structural information on rat islet amyloid polypeptide (rIAPP) monomers (M) and dimers (D) observed in the multiply charged state in the MS spectrum. MS/MS analysis indicated that the rIAPP monomers adopt distinct structures depending on the molecular ion charge state. Peptide bond dissociation between L₂₇ and P₂₈ was observed in the MS/MS spectra of rIAPP monomers, regardless of the monomer molecular ion charge state. MS/MS analysis of the dimers indicated that D⁵⁺ comprised M²⁺ and M³⁺ subunits, and that the peptide bond dissociation process between the L₂₇ and P₂₈ residues of the monomer subunit was also maintained. The observation of (M+ b₂₇)⁴⁺ and (M+ y₁₀)³⁺ fragment ions were deduced to originate from the two different D⁵⁺ complex geometries, the N-terminal and C-terminal interaction geometries, respectively. The fragmentation pattern of the [M_rIAPP + M_hIAPP]⁵⁺ MS/MS spectrum showed that the interaction occurred between the two N-terminal regions of M_rIAPP and M_hIAPP in the heterogeneous dimer (hetero-dimer) D⁵⁺ structure.