Publications by authors named "Sang Kang"

It has been known that ethanol causes neuronal cell death through oxidative stress. Ethanol itself and reactive oxygen species (ROS) produced by ethanol modulate intracellular signaling pathways including mitogen-activated protein kinase (MAPK) cascades. This study was conducted to examine the impact of ethanol on MAPK signaling in HT22 cells.

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New organic dyes composed of the benzo[b]furan donor, thiophene-conjugated bridge, and cyano acrylic acid acceptor have been newly synthesized through the one-pot coupling cyclization key step. Nanocrystalline TiO2 dye-sensitized solar cell was fabricated using this dye. A solar-to-electric conversion efficiency of 6.

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We have reported the template synthesis of a 90-membered macrocycle by olefin metathesis. The macrocycle 7 was prepared by an initial six-oxidative-addition reaction of 2 by [Pt(PEt(3))(4)]. The definite structure of a six-oxidative product was confirmed by the crystal structure.

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Lipoic acid is an essential disulfide cofactor required for the lipoate-dependent enzymes including pyruvate dehydrogenase (PDH), alpha-ketoglutarate dehydrogenase (KGDH), and glycine cleavage enzymes that function in key metabolic pathways in most prokaryotes and eukaryotes. Lipoic acid is covalently bound to lipoate-dependent enzymes by lipoate-protein ligase or lipoate transferase. Here, we characterized a lipoyl-protein ligase A (OsLPLA) gene of rice.

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DNA in most cells is regularly damaged by endogenous and exogenous mutagens. Unrepaired damage can result in apoptosis or may lead to unregulated cell growth and cancer. Inheritance of genetic variants at one or more loci results in reduced DNA repair capacity.

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In mammals, immediate-early transcription of the Period 1 (Per1) gene is crucial for resetting the mammalian circadian clock. Here, we show that CLOCK is a real signalling molecule that mediates the serum-evoked rapid induction of Per1 in fibroblasts through the Ca2+-dependent protein kinase C (PKC) pathway. Stimulation with serum rapidly induced nuclear translocation, heterodimerization and Ser/Thr phosphorylation of CLOCK just before the surge of Per1 transcription.

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The copper(II) ion in the syn-anti carboxylate-bridged one-dimensional zigzag chain title complex, {[Cu(C(16)H(18)N(3)O(2))]ClO(4)}(n), exhibits a distorted trigonal-bipyramidal environment. Two N atoms and one carboxylate O atom of the ligand form the basal plane, while the axial positions are filled by an N atom of the ligand and one O atom belonging to the carboxylate group of an adjacent molecule. The crystal packing is enhanced by C-H.

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Swine hepatitis E virus (HEV) is an emerging zoonotic pathogen due to its close genomic similarity to human HEV. The prevalence of swine HEV in the hepatic lesion of pigs from the Jeju Island was investigated by reverse transcriptase polymerase chain reaction (RT-PCR). In total, 40 pigs with hepatitis lesions were selected from 19 different farms, based on examination by microscopy.

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We investigated whether the snake venom toxin (SVT) from Vipera lebetina turanica inhibits cell growth of human prostate cancer cells by inducing apoptosis and also studied possible signaling pathways involved in this cell death. SVT inhibited growth of PC-3 and DU145 cells, androgen-independent prostate cancer cells, but not LNCaP cells, a human androgen-dependent prostate cancer cell. Cells were arrested in the G(2)-M phase by SVT with a concomitant decrease in the expression of the G(2)-M phase regulatory protein cyclin B1 and were also arrested in the G(1)-S phase with decreasing expression of cyclin-dependent kinase 4, cyclin D1 and cyclin E.

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Kainic acid (KA) induced oxidative stress is associated with hippocampal cell death. Recent studies suggest that curcumin, a potent antioxidant, may provide protection for KA-induced oxidative stress. We investigated the effects of curcumin treatment on hippocampal reactive astrocytes in mice with KA-induced seizures.

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Preparation of a triisocyanide ligand, 1,3,5-tris[(4-isocyano-3,5-diisoproyl-phenyl)ethynyl]benzene (5), is presented. Ligand 5 is obtained in three steps in 76% overall yield. Reaction of 5 with (eta5-Cp*)Rh(Cabs,s')(Cabs,s'= 1,2-S2C2B10H10-S,S') produced the rhodadithiolene adduct [[(eta5-Cp*)Rh(Cabs,s')(CNC6H2iPr2-2,6-CC-3)]3C6H3-1,3,5] (6).

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Recent findings have shown that, when expressed in the tripeptide platform, 'Fmoc-Glu-Xxx-Leu-amide', the phosphotyrosyl mimetic (pTyr), Xxx=(S)-3-carboxy-4-(carboxymethyl)-Phe, provides higher PTP-1B affinity than that obtained with Xxx=(S)-difluorophosphonomethyl-Phe (F(2)Pmp). This was of note, since difluorophosphonomethyl-containing pTyr mimetics have typically exhibited higher PTP-inhibitory potencies than carboxy-based mimetics, indicating the potential value of 3-carboxy-4-(carboxymethyl)-Phe as a starting point for further analogue development. Therefore, relying on precedence that alpha-fluorination often enhances PTP-1B affinity, (S)-3-carboxy-4-((carboxy)difluoromethyl)-Phe was designed as a PTP-1B-directed pTyr mimetic.

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Novel organic sensitizers comprising donor, electron-conducting, and anchoring groups were engineered at molecular level and synthesized. The functionalized unsymmetrical organic sensitizers 3-{5-[N,N-bis(9,9-dimethylfluorene-2-yl)phenyl]-thiophene-2-yl}-2-cyano-acrylic acid (JK-1) and 3-{5'-[N,N-bis(9,9-dimethylfluorene-2-yl)phenyl]-2,2'-bisthiophene-5-yl}-2-cyano-acrylic acid (JK-2), upon anchoring onto TiO2 film, exhibit unprecedented incident photon to current conversion efficiency of 91%. The photovoltaic data using an electrolyte having composition of 0.

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Zwitterionic silver nitrate salts of 1-(1-methyl-3-imidazolio)propane-3-sulfonate, 1-(1-methyl-1-pyrrolidinio)propane-3-sulfonate, and 1-(4-methyl-4-morpholio)propane-3-sulfonate have been prepared and tested as carriers for facilitated olefin transport membranes in the separation of ethylene/ethane, propylene/propane, and C4 mixtures. The interactions of olefins with silver ions bound to sulfonate groups were investigated by FTIR spectroscopy as well as the correlation between the binding affinity of olefins and facilitated transport.

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We recently demonstrated that prolonged maternal stress produces profound and long-lasting deficits in brain functions by programming a subset of target genes. We have now examined the possible effects of prenatal stress on the motility of adult offspring and dopamine (DA)-related gene expression in their midbrains, one of the target brain regions of stress hormones. Maternally stressed adult male mice showed impaired response habituation to novelty, and increased wheel-running activity associated with altered responses to DA receptor and DA transporter (DAT) blockers.

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Gold(I)-catalyzed cyclization of enynes containing an olefinic cycle has been studied. The introduction of an olefinic ring instead of a terminal alkene in enynes dramatically increased the yield of the reaction. Enynes having an olefinic cycle were prepared by a rhodium-catalyzed intermolecular [4 + 2] cycloaddition of diynes with butadiene.

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Angiogenin, a potent angiogenic factor, binds to endothelial cells and is endocytosed and rapidly translocated to and concentrated in the nucleolus where it binds to DNA. In this study, we report that angiogenin induces transient phosphorylation of protein kinase B/Akt in cultured human umbilical vein endothelial (HUVE) cells. LY294002 inhibits the angiogenin-induced protein kinase B/Akt activation and also angiogenin-induced cell migration in vitro as well as angiogenesis in chick embryo chorioallantoic membrane in vivo without affecting nuclear translocation of angiogenin in HUVE cells.

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Enhanced apoptosis has been observed in the placentas of women with preeclampsia, but few studies have examined changes at the molecular level. This study was designed to detect genes specifically expressed in full-term preeclamptic placentas. Tissue samples were collected immediately after cesarean delivery from 11 normal and 8 preeclamptic placentas at 35-40 weeks of gestation.

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The major obstacle for oral delivery of administered therapeutic proteins is malabsorption in the intestine. This malabsorption could be overcome by induction of neonatal FcRn [Fc (CH2 and CH3 domains of human IgG1 antibody) receptor]-mediated transcytosis in the intestine using recombinant fusion of CH2 and CH3 moieties of human IgG to a therapeutic protein. To this end we developed recombinant hGH (human growth hormone) fused to the N-terminus of Fc moieties [CH2-CH3 or h (hinge)-CH2-CH3] from human IgG1.

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The ketogenic diet (KD) is often effective for intractable epilepsy, but its antiepileptic mechanisms remain largely unknown. Within the cell death/survival pathway, Akt and its downstream protein Bad play an important role in kainic acid (KA)-induced cell death. Therefore, we investigated the effects of a KD on KA-induced changes in the Akt/Bad/14-3-3 signaling pathway by evaluating Akt, Bad, 14-3-3, and cleaved caspase-3 expression levels as well as their relative interactions.

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The Suzuki-coupling reaction of 2-(dihydroxyboryl)-3,4-dimethyl-2-cyclopenten-1-one and 2-(dihydroxyboryl)-3-methyl-2-cyclopenten-1-one with 2-bromoaniline derivatives affords cyclopentenone compounds from which cyclopentadiene compounds, 4,6-R'(2)-2-(2,5-Me2C5H3)C6H2NH2 and 4,6-R'(2)-2-(2,3,5-Me3C5H2)C6H2NH2 are prepared. After sulfonation of the -NH2 group with p-TsCl, metallation is carried out by successive addition of Ti(NMe2)4 and Me2SiCl2 affording o-phenylene-bridged Cp/sulfonamido titanium dichloride complexes, [4,6-R'(2)-2-(2,5-Me2C5H2)C6H2NSO2C6H4CH3)]TiCl2 (R'=H, ; R'=Me, ; R'=F, ) and [4,6-R'(2)-2-(2,3,5-Me3C5H)C6H2NSO2C6H4CH3)]TiCl2 (R'=H, ; R'=Me, ; R'=F, ). The molecular structures of and [2-(2,5-Me2C5H2)C6H4NSO2C6H4CH3)]Ti(NMe2)2 are determined by X-ray crystallography.

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A series of constrained geometry complexes of formula [(eta5-RC2B9H10)CH2(eta1-NMe2)]Al(Me) (R = H, 2a; Me, 2b) was prepared in high yields from the reaction of dicarbollylamine with trimethylaluminum. These complexes showed a unique constrained geometry structure with a central aluminum atom having eta5;eta1-coordination. DFT calculations further elaborate the electronic effect of an amine sidearm on the bonding capability of dicarbollyl ligand with an aluminum atom.

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Background: Alcohol has been shown to interfere with testosterone (T) release from Leydig cells. However, the mechanisms responsible for this phenomenon, which may include decreased activity of the luteinizing hormone-releasing hormone (LHRH)-LH axis, as well as a direct influence of the drug on the testes, are not fully understood. In this work, we investigated the influence of alcohol, administered intragastrically (i.

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Acute alcohol ingestion is well known to have deleterious effects on memory and also known to inhibit long-term potentiation, a putative cellular substrate of memory. In this study, we for the first time revealed that growth-associated protein 43 (GAP-43), which is well known as a presynaptic substrate of protein kinase C and one of the major synaptic plasticity-related genes, was down regulated by single ethanol administration (2.5 g/kg, 15% in saline, i.

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Ethanol has deleterious effects on neuronal cells both in vivo and in vitro, but the mechanisms are unknown. Here, treatment with increasing doses of ethanol (from 20 up to 600mM) decreased the viability of a mouse hippocampal neuroblastoma cell line, HT22. The glutathione concentration decreased and intracellular reactive oxygen species (ROS) increased in a dose-and time-dependent manner, suggesting that the neurotoxicity was due to oxidative stress.

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