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Trp-Lys-Tyr-Met-Val-Met (WKYMVM) is a novel potent peptide which can stimulate phosphoinositide hydrolysis in U937 as well as U266 and HL-60 cells (Baek et al., J. Biol. Chem. 271, 8170 (1996)). The peptide also induces superoxide generation in human neutrophils (Seo et al., J. Immunol. 158, 1896 (1997)). However, the signaling pathway down-stream of PLC set in motion by the peptide is not yet completely understood. We studied the signaling pathway of the peptide with the goal of elucidating the mechanism of the peptide's action. WKYMVM induced a rapid and transient activation of the ERKs in human histiocytic lymphoma cells, U937. The ERK1 activation peaked at 5 min and returned to the basal level after 30 min. The ERK1 stimulation by the peptide was partially inhibited by pretreatment of the cells with pertussis toxin (PTX), implicating G-protein involvement in the peptide's action. Pretreatment of staurosporine, protein kinase C (PKC) inhibitor, or PKC down-regulating PMA had no impact on the ERK1 activation by the peptide, indicating that the signaling pathway is independent of PKC activation. Pretreatment of the cells with neomycin and intracellular Ca2+ mobilizing reagents had also no effect on the ERK1 activation by the peptide. However, pretreatment with wortmannin or LY294002, the inhibitor of phosphatidylinositol 3 kinase (PI-3K), strongly inhibited peptide-stimulated ERK1 activation. Our results suggest that PI-3K may be an important participant in the ERK cascade induced by the peptide. Furthermore, the treatment of U937 cells with the peptide activated p74Raf-1, an upstream kinase of ERK. Taken together, our results suggest that the peptide activate ERK via a G-protein/PI-3K/Ras/Raf-1 mediated signaling pathway in U937 cells.

Ultraviolet-C (UVC) irradiation induces DNA damage and UVC-irradiated cells undergo cell growth arrest to repair the damaged DNA or the induction of apoptosis to prevent the risk of neoplastic transformation. Phospholipase C-gamma1 (PLC-gamma1) is a mediator of growth factor induced-signal cascade, catalyzing the hydrolysis of phosphatidyl 4,5-bisphosphate to generate second messengers, diacylglycerol and inositol 1,4,5-trisphosphate (IP(3)). PLC-gamma1 is activated by phosphorylation of tyrosine residues upon occupation of cell surface receptors by growth factors and plays an important role in controlling cellular proliferation and differentiation. In this study, we found that PLC-gamma1 was tyrosine phosphorylated within 2.5 min after UVC irradiation. To investigate the role of UVC-induced tyrosine phosphorylation of PLC-gamma1, we compared the effect of UVC between PLC-gamma1 overexpressing cells and empty vector transfected cells. Overexpression of PLC-gamma1 inhibited UVC-induced sub-diploid peak and DNA fragmentation. Northern blot analysis revealed that UVC-induced c-fos mRNA accumulation was inhibited in PLC-gamma1 overexpressing cells, while c-jun expression was not affected. In addition, UVC-induced activation of c-Jun N-terminal kinase (JNK) was significantly suppressed in PLC-gamma1 overexpressing cells. These results suggest that PLC-gamma1 may associate with the protective function against the UVC-induced cell death progression via the inhibition of accumulation of c-fos mRNA and the inhibition of JNK kinase activity.

A partial fragment of novel sequence (arr, adriamycin-resistant related) was previously identified using the differential display (DD)-PCR technique with adriamycin-resistant L1210 variant (L1210AdR), which shows a typical multidrug resistant (MDR) phenotypes. The present research shows the isolation of full length arr cDNA sequence. To clone the full length cDNA of arr gene, DD-PCR fragments were subjected to 5'- and 3'-Rapid Amplification of cDNA End (RACE) method. The cloned arr cDNA consisted of 770 bases and contained an open reading frame of 153 bases, encoding a protein of 51 amino acid with the molecular mass of 4 kDa by in vitro translation reactions. Northern blot analysis showed that a 770 bases transcript arr gene was overexpressed in adriamycin-resistant L1210 variant, but not in the parent suggesting that the arr gene may be involved in the adriamycin-resistant phenotypes.

We investigated electrical properties of transparent amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) with amorphous indium zinc oxide (a-IZO) transparent electrodes on a flexble thin glass substrate. The TFTs show a high field-effect mobility, a good subthreshold slope and a high on/off ratio owing to the high temperature thermal annealing process which cannot be applied to typical transparent polymer-based flexible substrates. Bias stress instability tests applying tensile stress concurrently with the bending radius of up to 40 mm indicated that mechanically and electrically stable a-IGZO TFTs can be fabricated on the transparent thin glass substrate.

Top of pageAbstract Hepatitis C virus (HCV) is the main etiological agent of chronic hepatitis, liver cirrhosis and hepatocellular carcinoma. Although the HCV infection causes worldwide health problem, efficient and specific antiviral therapy has not yet been developed. Thus, development of more specific and effective therapeutics against HCV is warranted. The RNA dependent RNA polymerase (NS5B) of HCV plays a central role in the viral replication. Therefore, NS5B is a good target for anti-HCV agents. Characteristics of RNAs which can adopt complex structures to bind target proteins with high affinities and encode amplificable genetic information make RNA a potentially very useful diagnostic and/or therapeutic lead compounds. Such short RNA ligands, termed RNA aptamers, have been identified from a random RNA library to bind several proteins with high affinity and specificity using in vitro selection techniques, called systemic evolution of ligands by exponential enrichment (SELEX). In the present study, we isolated RNA aptamers to NS5B from a combinatorial RNA library using SELEX techniques and analyzed the biochemical and biological functions of the RNA aptamers. The RNA aptamers were found to specifically and avidly bind NS5B with an apparent Kd of 1.3|[sim]|4 nM. Through enzymatic probing and footprinting analysis, critical regions of the RNAs for NS5B binding have been identified. Moreover, in vitro RNA synthesis by NS5B was significantly inhibited by the RNA aptamers. Interestingly, the RNA aptamers can be utilized as substrates for de-novo RNA synthesis by NS5B. Specific interaction between the RNAs and NS5B was confirmed by Maldi-Tof analysis of the aptamer-bound proteins in liver cells with HCV replicon. Importantly, the replication of HCV replicon in liver cells was efficiently inhibited by cytoplasmic expression of the RNA aptamers, but not by nuclear expression of the RNAs. In addition, we showed that these aptamers could function as decoys in HCV replicon cells, explaining the mechanism underlying inhibition phenomena of HCV replicon replication observed in cells by the specific RNA aptamers against HCV NS5B. These results suggest that the RNA aptamers could be useful not only as therapeutic and diagnostic agents of HCV infection but also as a powerful tool for the study of HCV replication mechanism.

We studied the bias stress instability of amorphous In–Ga–Zn–O (a-IGZO) thin-film transistors (TFTs) by varying the active layer thickness (t) from 6 to 100 nm. We found that the stretched exponential relationship between the threshold voltage shift and the stress time can be explained by oxygen dispersive diffusion which is absorbed near the back channel region during an oxygen annealing process in the active layer. For an a-IGZO TFT with t=6 nm, direct exposure of the channel layer to the ambient oxygen greatly increases the bias stress instability and induces hump like characteristics, indicating that the creation of acceptor-like states is the dominant mechanism of the instability of a-IGZO TFTs with a thin active layer.

We demonstrate high operating voltage transparent thin-film transistors (HVTTFTs) using amorphous InGaZnO (a-IGZO) active layers by introducing a high resistance bulk region in the source/drain electrodes. The HVTTFTs are operated at above VDS = 100 V with a high on/off current ratio and a good subthreshold slope. The electrical characteristics of the HVTTFTs were dominantly affected by Schottky contact resistance for small off-set length, and bulk resistance for large off-set length, indicating that optimization of the off-set length is a key factor to realize high performance HVTTFTs.

The effects of back channel interfacial states (N bit ) that can be generated by passivation layer deposition for amorphous indium gallium zinc oxide thin-film transistors (a-IGZO TFTs) by using an ATLAS 2D device simulator are analysed. As N bit is increased, the positive shift of threshold voltage (V TH ) is observed for thin and thick active layer TFTs due to the acceptor-like characteristics of interfacial states. However, as N bit is further increased, the V TH shift of the thick active layer TFT is eventually saturated, while that of the thin active layer TFT is continuously increased. This is because the characteristics of the a-IGZO TFT with a thin active layer are strongly affected by N bit , which can be used for optimising the performance of a-IGZO TFTs.

We fabricated thin film transistors (TFTs) using HfInZnO thin films as active channel layers. The thin films of HfInZnO were deposited by co-sputtering from HfO 2 and InZnO targets. The HfInZnO TFTs were investigated according to the radio-frequency power applied to the HfO 2 target. The transistor on and off currents were greatly influenced by the composition of Hf atoms suppressing the formation of oxygen vacancies. The electrical characteristics of the TFTs show a field-effect mobility of 3.53 cm 2 V ―1 s ―1 , a threshold voltage of 1.28 V, an on/off ratio of 1.4 × 10 ―7 , and a subthreshold swing of 95 mV/dec.

Purpose: This cross-sectional study was designed to identify anger-expression types in late school-age children and to investigate the relation of anger and the anger-expression type to their eating disorders. Method: Two hundred fifty four children in elementary school were recruited from 14 to 25, April, 2008. The data were analyzed by using descriptive statistics, cluster analysis, t-test, ANOVA, and Tukey's multiple comparison test. Result: Three anger-expression types in late school-age children were found; Anger-in/out, Anger-control, and Low anger-expression types. Children frequently using the anger-out/in type among the three types and with a higher trait anger reported higher eating disorders. Particularly trait anger and unhealthy anger expression type were linked to eating disorders. Conclusion: This study suggests that a specific anger management program needs to be developed for late school-age children with high trait anger and frequently using the anger out/in expression type and Anger-control type than low anger-expression types. Further research needs to be done with large samples and discussed in terms of the role of gender in eating disorders.

Conventional Doherty amplifiers usually use a class-A or class-ABamplifier for the main amplifier to maintain high linearity while inher-ently showing low efficiency. Presented is a high efficiency Dohertyamplifier that employs a class-E amplifier as the main amplifier andalso improves the linearity using the g

Background : Obesity is the most common nutritional disorder in Western society as well as in Korea. Obesity results from a combination of genetic, environmental, and behavioral factors. Materials and Methods : In an attempt to investigate the association of obesity with its candidate genes, adrenergic receptor () and uncoupling protein 2 (UCP2), we analyzed polymorphisms of Trp64Arg and UCP2 -866G/A by PCR-RFLP analysis and the obesity-related phenotypes, including body mass index (BMI), fasting glucose concentration, and plasma lipid profiles in 750 subjects. Results : The Trp64Arg polymorphism in the gene was not statistically associated with the BMI. The UCP2 -866G/A polymorphism was significantly higher in obese than in non-obese subjects (P Trp64Arg polymorphism.

Background : Up-regulation of the hepatocyte growth factor (HGF), its transmembrane tyrosine kinase receptor (c-Met), and urokinase type plasminogen activator (uPA), is associated with the development and metastasis of various types of cancers. However, the mechanisms by which HGF/c-Met signaling mediates cancer progression and metastasis are unclear. Methods : We investigated the roles of HGF/c-Met in tumor progression and metastasis in NUGC-3 and MKN-28 stomach cancer cell lines. Results : Treatment with HGF increased c-Met phosphorylation in a dose-dependent manner, as well as increasing cell proliferation. HGF treatment also increased the protein level and the activity of uPA in NUGC-3 and MKN-28 cells. A monoclonal antibody against human uPA receptor (uPAR), mAb 3936, inhibited HGF-mediated tumor cell invasion in a dose-dependent manner. Down-regulation of uPA using uPA-shRNA induced a decrease in in vitro cell invasion in NUGC-3 cells. Conclusions : These results suggest that NUGC-3 and MKN-28 cells express functional c-Met, which may provide a therapeutic target for interfering with metastases of cancer cells by inhibiting uPA and uPAR-mediated proteolysis.

Background: Doxorubicin has proved to be a useful chemotherapeutic agent especially for osteogenic sarcoma. It induces cancer cell death via apoptosis. Materials and Methods: To explore and analyze the changes of gene expression during doxorubicin induced apoptosis on human osteogenic sarcoma, Saos-2 cell, cDNA microarray was performed. After treatment with doxorubicin, total RNA was purified and expressed genes were investigated with a 17k human cDNA microarray. Results: For analysis of the cDNA microarray, the genes were filtered using the sum of the median value of Cy3 and Cy5 signal intensity of greater than 800. Expression of 264 genes was changed by more than 2 fold, and the expression of 35 genes was changed more than 3 fold after treatment with doxorubicin. The genes were primarily related to cell death, cell growth and maintenance, signal transduction, cellular component, transport, and metabolism. Conclusion: Treatment with doxorubicin induced expressional change of many genes. Some of the genes might be related with apoptosis directly or indirectly. Further study is now needed to characterize these genes.

Glutathione (GSH) is a well-known antioxidative cellular component which is ubiquitous in nature. Several enzymes involved in GSH metabolism and recycling have been found to play important roles in detoxification of xenobiotics and free radicals. In this study, total GSH content, activity of GSH peroxidase and GSH reductase were measured in liver and kidney of cisplatin treated rats. Total GSH content (mM/g protein) of liver was higher in cisplatin treated rats () than of nontreated control (), and in kidney, it was also higher in cisplatin treated rats () than that of control (). The activity of GSH peroxidase ( protein/min) was lower in liver of cisplatin treated rats () than that of control (), in kidney it was increase din cisplatin treated rats () compared to control (). The activity of GSH reductase ( protein/min) was higher in liver of cisplatin treated rats () than that of control (), in kidney it was also higher in cisplatin treated rats () than that of control (). In summary, detoxification of ciplatin was revealed lesser effect in kidney as show increasion of GSH peroxidase and reductase and detoxification of cisplatin was expressed effectively in liver by increasing of GSH content and decreasing GSH peroxidase.

GTP binding protein (G-protein) associated with membrane and involved in signal transduction was isolated from bovine brain, and molecular weight of G protein was observed. As the results, cell membranes were homogenized from bovine brain tissues and proteins of membrane were gained using 1% cholate, and progressed the chromatography. The purification process was performed by step, DEAE-Sephacel, Ulttrogel AcA 34 and heptylamine-Sepharose column chromatography. The chromatographic fractions were confirmed by GTP binding assay and SDS-polyacrylamide gel electrophoresis. Molecular weight of was revealed 39,000 dalton and 36,000 dalton. One more step of heptylamine-Sepharose was enforced to purify the GTP binding protein. Finally I gained the GTP binding protein isolated subtype of and .

Multidrug resistance(MDR) phenotype is frequently observed in animal and human cancer cell lines selected for in vitro resistance to a single chemotherapeutic agent. It is characterized by the diminished drug accumulation and is related to the drug efflux mechanism in resistant cells. In the present study, adriamycin resistant cells(L1210- : adriamycin, : ) and vincristine resistant cells (L1210- : vincristine, : ) were produced from mouse lymphoblastic leukemia cell line L1210. Growth profiles of survived cells were observed for 5 days with MTT(thiazolyl blue) assay and resistance was compared with (drug concentration of 50% survival reduction in absorbance). Resistant cells proliferated more slowly than sensitive cell. Doubling times were 29.7hr in L1210, 68.7hr in L1210- and 58.2hr in . MDRs expressed as resistance factor were as follows, L1210- was 76.4 times for vincristine, L1210- was 96.4 times for adriamycin. The cell membrane proteins with three different M.W. were recognized to be related resistance, 220, 158, and 88 kd in L1210-, 158, 140 and 88 kd in L1210- by SDS-PAG electrophoresis. Cell surface membrane proteins were identified by radio-iodination and autoradiogram, their molecular weights were 158, 72.8, and 42.4 Kd in L1210-.

In rat kidney, the changes in concentrations of nucleotides and their derivatives during ischemia induced by renal artery ligation was measured quantitatively with high performance liquid chromatography(HPLC). After the ligation of renal artery for 60minutes, the concentrations of the nucleotides and derivatives were measured. In ischemic tissue, IDP was significantly decreased from in control to (p to (p to (P, to (P to (P to (p to (P to (P to (P

The development of multi drug-resistant tumor cell population is a major problem in the chemotherapy of human cancer. These cells are often cross resistant to unrelated drugs and the precise mechanisms of multidrug resistant phenotype of tumor cells has not been fully elucidated. Cisplatin resistant tumor cell(SNU-1/) was induced from human stomach cancer cell line(SNU-1) in vitro. Growth profiles of survival cells were observed during 5 days by thiazolyl blue (MTT) assay. To investigate the cross resistance of various anticancer drugs in SNU-1 and SNU-1/, We compared the value of - drug concentration at 50% survival of control and gained relative resistances (RR). The RR for SNU-1/ were as follows; vinblastine, > 43.0 ; epirubicin, 22.9 ; dactinomycin, 16.0 ; etoposide, 15.0 ; vincristine, 9.2 ; adriamycin, 5.7 ; aclarubicin, 5.3. But 5-fluorouracil, methotrexate, daunorubicin have not cross resistance with cisplatin. Resistant inhibition values of verapamil for SNU-1/ were as follows; vincristine, 13.1 ; epirubicin, 10.0 ; etoposide, 6.3 ; vinblastine, 4.4 ; dactinomycin, 3.6 ; daunorubicin, 2.4. Membrane proteins of 51,400 and 81,300 daltons were identified by radioiodination with SDS-PAGE, which might represented the drug resistance.

The objective of the present study was to identify the characteristics of phospholipase C (PLC) isozymes purified from bovine brain and to investigate their interrelationship with G protein. The purified PLC isozymes , and were obtained and the characteristics of PLC activity on various concentrations of free were observed. The activity of PLC was increased with increasing concentration and the activity PLC was increased higher in the presence of phosphatidyl choline(PC) than in the abscence of PC. For vesicle formation as the structure of cell membrane, cholic acid and deoxycholic acid as detergent on phosphatidylinositol bisphosphate() substrate containing PC were used, and then the activity of PLC isozymes were increased with increasing concentration of cholate, from 0.2% to 1% and were increased slightly in deoxycholate. In the containing phospholipid and glycolipid as brain extract, the activity of PLC isozymes were checked in 0.2%-1% cholic acid. The activities of PLC isoyzmes were continuously increased up to 1% cholic acid. The quantitation of PLC isozymes from several bovine organs by radioimmunoassay was made. Brain was the most sufficient organ in terms of amount of PLC and . A large amount of PLC was existed in adrenal gland. The binding capacity of GTPrS and G protein was observed and other observations of the binding effect of GTPrS-G protein and PLC monoclonal Ab-Protein A from tissue homogenate with PLC were made. From the observation the binding capacity was revealed the range of 0.11%-1.49%. The effects of each type of G protein on the percent activity of purified PLC isozymes were observed. From the observation, activities of isozymes were increased in & Gmix, and the activities of PLC and were increased in and . Activities of PLC and were decreased in but PLC increased.

p62 is a cytoplasmic ubiquitin chain binding protein. Upon a variety of extracellular signals, both transcript and protein levels of p62 were rapidly increased. These signals include phorbol 12-myristate 13-acetate (PMA) and calcium ionomycin for peripheral blood mononuclear cells, serum or PDGF for serum-starved NIH3T3 cells, IL-3 for the G1 arrested pre-B cell line Ba/F3, and PMA for a human promyelocyte line U937. The elevation of p62 transcript level is due to temporal stabilization of mRNA and rapid activation of the p62 gene. Cycloheximide-induced enhanced transcription suggests the immediate early response of the p62 gene. The rapid induction of p62 indicates the presence of a novel ubiquitination-mediated regulatory mechanism during cell proliferation and differentiation.

Band 3, the predominent 95,000 dalton anion transport protein, is the major intrinsic glycoprotein of the human erythrocyte membrane. This anion carrier exists as a dimer and binds the cytoskeletons such as spectrin, ankyrin and actin. And the liposomes are vesicular structures which form spontaneouly upon hydration of phospholipids. These artificial lipid vesicles have been investigated as model of the biological membranes and as a mean of improving the delivery of nucleic acids, drugs, proteins and biological substances to specific target tissues and cells. In this study, we were purified Band 3 from the human erythrocyte membrane(ghost) was prepared by hemolysis of intact human erythrocyte with weak alkali-hypotonic solution. Band 6 was removed from ghost by extracting with solution of an ionic strength of 0.15. Band 3 and Band 4 were solubilized selectively by extracting Band 6-depleted ghosts with Triton X-100 under nondenaturing conditions. Band 3 was then purified from Triton X-100 extract treated with p-chloromercuribenzoate by sucrose density gradient ultracentrifugation. This purified Band 3 was incorporated into liposomes prepared by reverse-phase evaporation. Phosphatidyl L-serine and cholesterol(1 : 1 molar ratio) were dissolved in chloroform and then chloroform was removed by rotatory evaporation under reduced pressure. Band 3 solution without Triton X-100 was introduced into a mixture of lipids and diethylether. Diethylether was subsequently removed by evaporation. This purified Band 3 and its incorporation into liposomes were confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

Cytochrome P-450(CP-450) is one of the three components of the liver microsomal enzyme system which hydroxylates fatty acids, hydrocarbons and a variety of drugs and other foreign compounds. Female Balb/c mice were immunized with purified polychlorinated bipheny(PCB)-induced CP-450 LMII. The spleen cells derived from immunized mice were fused with myeloma cells using polyethylene glycol(PEG 3500). The hybrid cells were selected by hypoxanthine-aminopterine and thymidine(HAT) medium and the culture fluid were screened by enzyme-linked immunosorbent assay to CP450 LMII. The hybrid cess() were innoculated into intraperitoneal cavity of Balb/c mice for the purpose of production of ascitic fluids. Monoclonal antibody(Mab) was purified from ascitic fluid by DEAE cellulose ion exchange chromatography and -labeled Mab was also confirmed by autoradiography and SDS-polyacrylamide gel electrophoresis (MW : 55,000 and 110,000).

The soil bacterium Agrobacterium tumefaciens is a plant pathogen that cause3 crown gall tumors by infecting the wounded dicotyledonous plants and subsequent integration of bacterial DNA into plant nuclear DNA. Virulent A. tumefaciens strains harbor a large Ti (tumor-inducing) plasmid that carries genes essential for tumorigenesis. In the present study, 13 strains (Malus pumila Mill; , Populus monilifera; , Populus tomentiglandlosa; and Rosa species; ) of Agrobacterium isolated in korean crown gall tumors and plasmids were observed in 6 strains (, , , , and ). The test for crown gall tumor formation was resulted only in ATCC15955 and strains inoculated into the stem of sun flower and the development was observed for 4 and 6 weeks after inoculation. Above two Ti plasmids (pTi) were purified by cesium chloride-ethidium bromide density gradient centrifugation and digested with restriction enzyme and fragments of pTiATCC 15955 and observed by EcoR I ; 25&27, Hind III; 23&21, BamH I ; each 20 and Hpa I ; 12&27, and sizes of pTiATCC15955 and and calculated as 200 and 87 kbases. Octopine was isolated from tumor tissue ( and ) and these strains confirmed as octopine type.