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Endoscopy 02/2013; 45(2):155. · 5.21 Impact Factor
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ABSTRACT: Background and study aims: Endoscopic bilateral drainage for inoperable malignant hilar biliary strictures (HBS) using metal stents is considered to be technically difficult. Furthermore, endoscopic revision of bilateral stenting after occlusion can be challenging. This study was performed to evaluate the long-term efficacy of endoscopic bilateral stent-in-stent placement of cross-wired metallic stents in high-grade malignant HBS and planned endoscopic bilateral revision. Patients and methods: A total of 84 patients with inoperable high-grade malignant HBS were enrolled from three academic tertiary referral centers. Two cross-wired metal stents were inserted using a bilateral stent-in-stent placement method. Bilateral endoscopic revision was also performed during follow-up using either identical metal stents or plastic stents. The main outcome measurements were technical and functional success, complications, stent patency, and endoscopic revision efficacy. Results: The technical and clinical success rates of endoscopic bilateral stent-in-stent placement of cross-wired metallic stents were 95.2 % (80 /84) and 92.9 % (78 /84), respectively. Median patency (range) and survival were 238 days (10 - 429) and 256 days (10 - 1130), respectively. Obstruction of primary bilateral stents occurred in 30.8 % (24 /78) of patients with functionally successful stent placement. The technical and clinical success rates of planned bilateral endoscopic revision for occluded stents were 83.3 % (20 /24) and 79.2 % (19 /24), respectively. For revision, bilateral metallic stents were placed in 11 patients (55.0 %); the remaining patients received plastic stents. Conclusions: Palliative endoscopic bilateral stent-in-stent placement of cross-wired metallic stents was effective in patients with inoperable HBS. Revision endoscopic bilateral stenting may be feasible and successful in cases where the primary deployed metal stents are occluded.
Endoscopy 12/2012; · 5.21 Impact Factor
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ABSTRACT: The incidence of residual stones after mechanical lithotripsy for retained common bile duct (CBD) stones is relatively high. Peroral cholangioscopy using a mother-baby system may be useful for confirming complete extraction of stones, but has several limitations regarding routine use. We evaluated the role of direct peroral cholangioscopy (DPOC) using an ultraslim upper endoscope for the evaluation and removal of residual CBD stones after mechanical lithotripsy.
From August 2006 to November 2010, 48 patients who had undergone mechanical lithotripsy for retained CBD stones with no evidence of filling defects in balloon cholangiography were recruited. The bile duct was inspected by DPOC after balloon cholangiography. Detected residual CBD stones were directly retrieved with a basket or balloon catheter under DPOC. The incidence of residual stones detected by DPOC, and the success rate of residual stone retrieval under DPOC were investigated.
DPOC was successfully performed in 46 of the 48 patients (95.8%). Of these, 13 patients (28.3%) had residual CBD stones (mean number 1.4, range 1-3; mean diameter 4.5 mm, range 2.3-9.6). The residual stones were removed directly under DPOC in 11 of these patients (84.6%). There were no complications associated with DPOC or stone removal.
DPOC using an ultraslim upper endoscope is a useful endoscopic procedure for the evaluation and extraction of residual stones after mechanical lithotripsy for retained CBD stones.
Endoscopy 07/2012; 44(9):819-24. · 5.21 Impact Factor
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ABSTRACT: Moving bed bioreactors (MBBR) and fixed bed bioreactors (FBBR) were compared for biological phosphorus removal and denitrification. The sorption denitrification P-elimination (S-DN-P) process was selected for this study. Results indicated that all nutrients were removed by the FBBR process compared with the MBBR process: 19.8% (total COD), 35.5% (filtered COD), 27.6% (BOD(5)), 62.2% (acetate), 78.5% (PO(4)-P), and 54.2% (NO(3)-N) in MBBR; 49.7% (total COD), 54.0% (filtered COD), 63.2% (BOD(5)), 99.6% (acetate), 98.6% (PO(4)-P), and 75.9% (NO(3)-N) in FBBR. The phosphate uptake and NO(3)-N decomposition in the FBBR process during the denitrification phase were much higher than for the MBBR process despite being of shorter duration. Results obtained from this study are helpful in elucidating the practical implications of using MBBR and FBBR for the removal of bio-P and denitrification from wastewater.
Water Science & Technology 01/2012; 65(10):1834-8. · 1.12 Impact Factor
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Endoscopy 12/2011; 43 Suppl 2 UCTN:E390-1. · 5.21 Impact Factor
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ABSTRACT: The anti-human rhinovirus (HRV) activity of orobol 7-O-d-glucoside (O7G) from Lagerstroemia speciosa L. (Lythraceae) was evaluated in Hela cells.
We tested anti-HRV activity of O7G using a cytopathic effect (CPE) reduction method, which exhibited broad-spectrum anti-HRVs activity with a 50% inhibitory concentration (IC(50)) ranging from 0.58 to 8.80 microg ml(-1). The 50% cytotoxicity concentration (CC(50)) of O7G is more than 100 microg ml(-1), and the derived therapeutic indices are more than 12. Ribavirin didn't possess antiviral activity against HRV15, HRV3 and HRV5, but exhibited weak antiviral activity against HRV2 and HRV3, and showed strong anti-HRV6 and -14 activities.
These results suggest that O7G is a novel drug class with broad spectrum antiviral activity against HRV species A (HRV1B, HRV2, HRV15 and HRV40) and species B (HRV3, HRV6 and HRV14), as well as pleconaril-resistant virus (HRV5).
Therefore, these findings provide important information for the utilization of Q7G promising broad spectrum for human rhinovirus treatment.
Letters in Applied Microbiology 03/2010; 51(1):1-5. · 1.62 Impact Factor
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ABSTRACT: The anti-enterovirus 71 (EV71) activity of six Nepalese plants' extracts and gallic acid (GA) isolated from Woodfordia fruticosa Kurz (family; Lythaceae) flowers were evaluated in Vero cells.
The anti-EV71 activity of tested compounds was evaluated by a cytopathic effect reduction method. Our results demonstrated that flowers' extracts of W. fruticosa exerted strong anti-EV71 activity, with a 50% inhibitory concentration (IC(50)) of 1.2 microg ml(-1) and no cytotoxicity at a concentration of 100 microg ml(-1), and the derived therapeutic index (TI) was more than 83.33. Rivabirin showed no antiviral activity against EV71. Furthermore, GA isolated from W. fruticosa flowers exhibited a higher anti-EV71 activity than the extract of W. fruticosa flowers, with an IC(50) of 0.76 microg ml(-1) and no cytotoxicity at a concentration of 100 microg ml(-1), and the derived TI was 99.57.
This study demonstrated that flower extracts of W. fruticosa possessed anti-EV71 activity and GA isolated from these flowers showed stronger anti-EV71 activity than that the extracts.
Our results suggest that the GA from W. fruticosa flowers may be used as a potential antiviral agent.
Letters in Applied Microbiology 01/2010; 50(4):438-40. · 1.62 Impact Factor
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ABSTRACT: RNA viruses are a major source of respiratory diseases worldwide. The lack of effective therapeutical treatment underlines the importance of research for new antiviral compounds. Raoulic acid is a principal ingredient of the plant Raoulia australis Hook. F. Antiviral assay using cytopathic effect (CPE) reduction method showed that raoulic acid possessed strong antiviral activity against human rhinovirus 2 (HRV2) with a 50% inhibition concentration (IC(50)) value of less than 0.1mug/ml, human rhinovirus 3 (HRV3) with a IC(50) value of 0.19 microg/ml, coxsackie B3 (CB3) virus with IC(50) values of 0.33 microg/ml, coxsackie B4 (CB4) virus with IC(50) values of 0.40 microg/ml, and enterovirus 71 (EV71) virus with IC(50) values of less than 0.1 microg/ml. However, the compound did not possess antiviral activity against influenza A (Flu A/PR, Flu A/WS, H1N1) and B viruses at four concentrations ranging from 0.1 to 100 microg/ml.
Phytomedicine: international journal of phytotherapy and phytopharmacology 01/2009; 16(1):35-9. · 2.17 Impact Factor
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ABSTRACT: The seroprevalence of hepatitis A virus (HAV) antibodies is low in young adults in Korea. From May to July 2005, 17 cases of HAV were reported from healthcare workers (HCWs) in a hospital intensive care unit (ICU). We looked for the presence of anti-HAV IgM from all patients in the medical-surgical ICU with elevated aspartate aminotransferase (AST) and alanine aminotransferase (ALT) and screened AST and ALT levels in all HCWs who came into contact with two suspected index cases. Once the outbreak was confirmed, the molecular subtypes of HAV from the blood of HCWs were determined. Index cases and a transmission route were identified, and intervention strategies applied to control the outbreak. The 17 HCW cases included 13 nurses and four doctors aged 22-32 years, who each suffered acute HAV infection during the study period. The possible transmission of HAV was via the faecal-oral route from bedridden patients with diarrhoea. All HCWs were positive for anti-HAV IgM and eight were positive for HAV RNA. Analysis of the VP1-2A region of each isolate showed genotype IA in five strains and co-circulation of genotypes IA and IB in the others. This HAV outbreak highlights the importance of standard infection control precautions within a hospital. Molecular study of patients' blood would be useful for clarifying the epidemiology of a suspicious HAV outbreak in a hospital.
Journal of Hospital Infection 11/2007; 67(2):175-81. · 3.39 Impact Factor
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ABSTRACT: Multi-walled carbon nanotube (MWNT) nanocomposites with poly(methyl methacrylate) were prepared via both an in situ bulk polymerization and a suspension polymerization using a radical initiator of 2,2-azobisisobutyronitrile (AIBN). Prior to the syn-thesis, the MWNT was purified in an acidic solution to remove impurities such as metallic catalysts and amorphous carbons. The AIBN induced PMMA was grafted on the MWNT, which was confirmed by a Fourier transform infrared spectrometer (FT-IR). The composite morphology of the MWNT was observed by scanning electron microscopy (SEM). Electrical characteristics were further examined via both a four-probe method and a rotational rheometer equipped with a high voltage generator.
80.Sg. 07/2004; 81.
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ABSTRACT: Ceramides are naturally occurring compounds recognized to mediate apoptosis. N-acylsphingosines, containing a double bond at carbons 4 and 5 of their sphingoid backbone, are thought to be the active form, because N-acylsphinganines with completely saturated sphingoid are inactive. In the present study, we synthesized a series of N-acyl-4D-ribo-phytosphingosines (phytoceramides) that contain a hydroxyl group at carbon 4 and investigated structure-cytotoxicity relationship of the presumed functional groups in ceramides. N-Acetylphytoceramide (PCer2) and N-hexanoylphytoceramide (PCer6) were found to be more cytotoxic than ceramides as determined by released lactate dehydrogenase activity and morphological criteria. This was not caused by intracellular conversion of phytoceramides to ceramides, because no N-hexanoylsphingosine was formed after incubation of cell lysate with PCer6. Among phytoceramides having acyl chains two to eight carbons long, the cytotoxicity was highest with five or six carbons. The carbonyl group of the amide bond did not seem to be critical, because substitution of the oxygen with sulfur did not influence the cytotoxicity. The phytoceramide-induced cell death was observed to be apoptotic in nature with the use of terminal deoxynucleotidyl transferase dUTP nick-end labeling and propidium iodide staining. Because phytoceramides can be readily synthesized from yeast sources, they may present a potential and economical alternative to ceramide in future studies and therapies.
Molecular Pharmacology 06/2001; 59(5):1249-55. · 4.88 Impact Factor
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ABSTRACT: We have investigated the structure and phase behavior of nonmolecularly layered silver stearate by means of temperature-dependent
diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. Upon heating the sample, remarkable spectral changes
took place. The first phase transition took place that might be associated with a premelting event characterized by the formation
of gauche conformers at 390-420 K. A second phase transition took place in which silver nanoparticles with a size of ∼4 nm
were formed by thermal decomposition of silver stearate at 520-550 K. These silver nanoparticles, derivatized by stearate,
were readily spread as a monolayer at air/water interface, and could be packed in 3-D assemblies by the Langmuir-Blodgett
method.
The European Physical Journal D 01/2001; 16(1):293-296. · 1.48 Impact Factor
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ABSTRACT: The underlying cause of the selective death of the nigral dopaminergic neurons in Parkinson's disease is not fully understood. Tetrahydrobiopterin (BH4) is synthesized exclusively in the monoaminergic, including dopaminergic, cells and serves as an endogenous and obligatory cofactor for syntheses of dopamine and nitric oxide. Because BH4 contributes to the syntheses of these two potential oxidative stressors and also undergoes autoxidation, thereby producing reactive oxygen species, it was possible that BH4 may play a role in the selective vulnerability of dopaminergic cells. BH4 given extracellularly was cytotoxic to catecholamine cells CATH. a, SK-N-BE(2)C, and PC12, but not to noncatecholamine cells RBL-2H3, CCL-64, UMR-106-01, or TGW-nu-1. This was not caused by increased dopamine or nitric oxide, because inhibition of their syntheses did not attenuate the damage and BH4 did not raise their cellular levels. Dihydrobiopterin and biopterin were not toxic, indicating that the fully reduced form is responsible. The toxicity was caused by generation of reactive oxygen species, because catalase, superoxide dismutase, and peroxidase protected the cells from the BH4-induced demise. Furthermore, thiol agents, such as reduced glutathione, dithiothreitol, beta-mercaptoethanol, and N-acetylcysteine were highly protective. The BH4 toxicity was initiated extracellularly, because elevation of intracellular BH4 by sepiapterin did not result in cell damage. BH4 was spontaneously released from the cells of its synthesis to a large extent, and the release was not further enhanced by calcium influx. This BH4-induced cytotoxicity may represent a mechanism by which selective degeneration of dopaminergic terminals and neurons occur.
Molecular Pharmacology 10/2000; 58(3):633-40. · 4.88 Impact Factor
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S. Baang,
S.H. Baek, H.J. Choi,
E.J. Chung,
Y.B. Chang,
J.H. Kim,
J.S. Kim,
K. Kim,
M.K. Kim,
S.B. Kim,
Y.J. Kim,
S.I. Lee,
S.Y. Lee,
Y.H. Lee,
H. Park,
K.R. Park,
C. Winter,
C.S. Yoon
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ABSTRACT: SSTF (Samsung Superconductor Test Facility) has been built with
the primary goal of testing the KSTAR TF (Toroidal Field) and PF
(Poloidal Field) magnets as well as CICC (Cable-in-Conduit Conductor)
and superconducting strands in the most relevant manner. The facility is
located at SAIT (Samsung Advanced Institute of Technology) near the
KSTAR project home site. Two helium liquefiers of 120 liter/hr capacity
have been utilized as refrigerators demonstrating simultaneous double
mode operation of refrigeration and liquefaction. A forced flow
supercritical helium cooling circuit allows the test facility to be
operated at temperatures down to 4.5 K. Other major SSTF components are
a large vacuum vessel (6 m diameter and 7.3 m height) with liquid
nitrogen temperature shield, data acquisition and control system with
EPICS (Experimental Physics and Industrial Control System), current
leads, and 50 kA modular power supply with fast dump quench protection
circuitry. SSTF has been used for the first test-phase of KSTAR CICC
sample. The current status of SSTF as the KSTAR magnet test facility for
components and qualification test is presented in detail
IEEE Transactions on Appiled Superconductivity 04/2000; · 1.04 Impact Factor
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ABSTRACT: Polymer-induced turbulent drag reduction in a rotating disk apparatus was investigated using nonionic poly(ethylene oxide)
(PEO) in a synthetic saline solution with novel application to ocean thermal energy conversion technology. A maximum total
(skin friction plus form) drag reduction of 30% was obtained with 50 wppm of PEO with molecular weight 5.0 × 106. The concentration dependence of the percentage drag reduction for the PEO/saline solution system is found to fit Virk's
empirical correlation, and a universal correlation for various molecular weights and Reynolds numbers is also presented. Furthermore,
hydrodynamic volume fraction was introduced to correlate drag reduction efficiency with molecular parameters in this PEO/saline
solution system.
Colloid and Polymer Science 01/2000; 278(7):701-705. · 2.33 Impact Factor
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ABSTRACT: GTP cyclohydrolase I (GTPCH) catalyzes the first and rate-limiting reaction in the synthesis of tetrahydrobiopterin (BH4), an obligatory co-factor for monoamines and nitric oxide syntheses. Roles of calcium influx on transcript, protein and activity levels of GTPCH and BH4 availability were studied using primary cultured bovine adrenal medullary cells. Bovine GTPCH cDNA was isolated and used in Northern blot analyses. Ionomycin, A23187 and BayK8644 dramatically up-regulated GTPCH mRNA level. Depolarization by potassium or veratridine also induced GTPCH expression, which was abolished by EGTA. A23187 elevated GTPCH protein level, enzyme activity, and BH4 levels. Thus, calcium influx up-regulates GTPCH gene expression and BH4 levels which may contribute to neurotoxicity directly and/or via elevation of dopamine and nitric oxide.
Neuroreport 12/1999; 10(17):3611-4. · 1.66 Impact Factor
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ABSTRACT: We have previously reported that the cAMP/protein kinase A (PKA) pathway is important in the gene regulation of both induction and basal expressions of the catecholamine synthesizing enzymes tyrosine hydroxylase (TH) and dopamine beta-hydroxylase (DBH). The neuropeptide pituitary adenylate cyclase activating polypeptide (PACAP) has been shown to activate the intracellular cAMP/PKA pathway. In the present study, using primary cultured bovine adrenal medullary cells, we determined whether the basal activity of the PACAP receptor might play a role in the maintenance of the basal expression of these enzyme genes via the cAMP/PKA pathway. The potent PACAP receptor antagonist PACAP (6-38) caused a reduction of TH and DBH mRNA levels in a dose dependent manner as well as their enzyme activities and TH protein level. The effects of PACAP (6-38) and the PKA inhibitor H-89 exhibited generally similar trends, and were not additive in the reduction of TH and DBH gene expression and activities, suggesting that they take a common intracellular signaling pathway. The antagonist also caused decreases in the intracellular norepinephrine and epinephrine levels similar to the effect of H-89. Taken together, the data suggests that PACAP is involved in the regulation of maintenance of the catecholamine synthesizing enzymes TH and DBH by utilizing the cAMP/PKA pathway.
Molecules and Cells 05/1999; 9(2):146-51. · 2.18 Impact Factor
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ABSTRACT: The generation of nitric oxide (NO) aggravates neuronal injury. (6R)-5,6,7,8-Tetrahydro-L-biopterin (BH4) is an essential cofactor in the synthesis of NO by nitric oxide synthase (NOS). We attempted to attenuate neuron degeneration by blocking the synthesis of the cofactor BH4 using N-acetyl-3-O-methyldopamine (NAMDA). In vitro data demonstrate that NAMDA inhibited GTP cyclohydrolase I, the rate-limiting enzyme for BH4 biosynthesis, and reduced nitrite accumulation, an oxidative metabolite of NO, without directly inhibiting NOS activity. Animals exposed to transient forebrain ischemia and treated with NAMDA demonstrated marked reductions in ischemia-induced BH4 levels, NADPH-diaphorase activity, and caspase-3 gene expression in the CA1 hippocampus. Moreover, delayed neuronal injury in the CA1 hippocampal region was significantly attenuated by NAMDA. For the first time, these data demonstrate that a cofactor, BH4, plays a significant role in the generation of ischemic neuronal death, and that blockade of BH4 biosynthesis may provide novel strategies for neuroprotection.
Journal of Neuroscience 03/1999; 19(3):878-89. · 7.11 Impact Factor
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ABSTRACT: Roles of protein kinase A (PKA) and protein kinase C (PKC) in regulation of tyrosine hydroxylase, dopamine beta-hydroxylase, and phenylethanolamine N-methyltransferase expression by pituitary adenylate cyclase-activating polypeptide (PACAP) were determined in primary cultured bovine chromaffin cells. DBH up-regulation by PACAP was reduced by H-89 and not further increased by forskolin showing involvement of cAMP/PKA. It was not mediated by PKC, as 12-O-tetradecanoylphorbol-13-acetate and sphingosine exerted no effect. Tyrosine hydroxylase induction by PACAP was mediated by both kinases. The PACAP-activated PKA up-regulated phenylethanolamine N-methyltransferase expression whereas PKC caused down-regulation. PACAP increased tyrosine hydroxylase and dopamine beta-hydroxylase activities, but slightly lowered phenylethanolamine N-methyltransferase activity, resulting in a preferential rise in norepinephrine over epinephrine.
Peptides 02/1999; 20(7):817-22. · 2.43 Impact Factor
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ABSTRACT: The turbulent drag reduction characteristics of the rod-like polysaccharide xanthan gum dissolved in water was investigated using a rotating disk apparatus. The ultrasonic degradation method was adopted to obtain polymer fractions of different molecular weights of xanthan gum for this study. The drag reduction curve was then plotted to observed the universal characteristics of xanthan gum, and the intrinsic concentration was found to be an extremely useful quantity in normalizing the drag reduction data for different molecular weights.
Macromolecular Rapid Communications 12/1998; 19(8):419 - 422. · 4.60 Impact Factor
