Showing papers by "Hye Jin Lee published in 2012"

Nanoparticle-enhanced surface plasmon resonance detection of proteins at attomolar concentrations: comparing different nanoparticle shapes and sizes.

Abstract: The application of biofunctionalized nanoparticles possessing various shapes and sizes for the enhanced surface plasmon resonance (SPR) detection of a protein biomarker at attomolar concentrations is described. Three different gold nanoparticle shapes (cubic cages, rods and quasi-spherical) with each possessing at least one dimension in the 40–50 nm range were systematically compared. Each nanoparticle (NP) was covalently functionalized with an antibody (anti-thrombin) and used as part of a sandwich assay in conjunction with a Au SPR chip modified with a DNA-aptamer probe specific to thrombin. The concentration of each NP-antibody conjugate solution was first optimized prior to establishing that the quasi-spherical nanoparticles resulted in the greatest enhancement in sensitivity with the detection of thrombin at concentrations as low as 1 aM. When nanorod and nanocage antibody conjugates were instead used, the minimum target concentrations detected were 10 aM (rods) and 1 fM (cages). This is a significan...

Detection of Glaucoma Progression by Assessment of Segmented Macular Thickness Data Obtained Using Spectral Domain Optical Coherence Tomography

Abstract: PURPOSE. We evaluated the clinical use of segmented macular layer thickness measurement in terms of glaucoma diagnosis and the ability to detect progression, and to compare such outcomes to those by circumpapillary retinal nerve fiber layer (cRNFLT) and total macular thickness (TMT) measurements. METHODS. The study included 141 glaucomatous and 61 healthy eyes. All glaucomatous eyes were subjected to at least four spectral domain optical coherence tomography (SD-OCT) examinations (mean follow-up, 2.13 years). Segmented macular layers were the macular nerve fiber layer (NFL), ganglion cell and inner plexiform layer (GCA), and outer retinal layer (ORL; from outer plexiform layer to retinal pigment epithelium). Areas under receiver operating characteristic curves (AUCs) discriminating healthy from glaucomatous eyes were determined in baseline measurements. The sensitivity and specificity of these parameters in terms of glaucoma progression detection were determined, with reference to assessment of optic disc/retinal nerve fiber layer (RNFL) photographs/visual field (VF) deterioration as standard(s). RESULTS. GCA afforded the best diagnostic performance among three macular layers. The AUC of the GCA thickness (GCAT) was less than that of cRNFLT (0.869 vs. 0.953, P ¼ 0.018), but superior to that of TMT (0.790, P ¼ 0.05). Of the eyes, 38 showed progression during follow-up by standard methods. The sensitivities of TMT, GCAT, and cRNFLT values in terms of detection of progression were 14%, 8%, and 5%, respectively. CONCLUSIONS. Although baseline cRNFL measurement was optimal in terms of glaucoma diagnosis, the GCAT and TMT showed similar levels of sensitivity in progression detection. (Invest Ophthalmol Vis Sci. 2012;53:3817‐3826) DOI:10.1167/iovs.11-9369

IL-33 induces Th17-mediated airway inflammation via mast cells in ovalbumin-challenged mice.

Abstract: Allergic asthma is characterized by infiltration of eosinophils, elevated Th2 cytokine levels, airway hyperresponsiveness, and IgE. In addition to eosinophils, mast cells, and basophils, a variety of cytokines are also involved in the development of allergic asthma. The pivotal role of eosinophils in the progression of the disease has been a subject of controversy. To determine the role of eosinophils in the progression of airway inflammation, we sensitized and challenged BALB/c wild-type (WT) mice and eosinophil-deficient ΔdblGATA mice with ovalbumin (OVA) and analyzed different aspects of inflammation. We observed increased eosinophil levels and a Th2-dominant response in OVA-challenged WT mice. In contrast, eosinophil-deficient ΔdblGATA mice displayed an increased proportion of mast cells and a Th17-biased response following OVA inhalation. Notably, the levels of IL-33, an important cytokine responsible for Th2 immune deviation, were not different between WT and eosinophil-deficient mice. We also demonstrated that mast cells induced Th17-differentiation via IL-33/ST2 stimulation in vitro. These results indicate that eosinophils are not essential for the development of allergic asthma and that mast cells can skew the immune reaction predominantly toward Th17 responses via IL-33 stimulation.

Highly sensitive electrochemical detection of proteins using aptamer-coated gold nanoparticles and surface enzyme reactions

Abstract: A novel electrochemical detection methodology is described for the femtomolar detection of proteins which utilizes both DNA aptamer-functionalized nanoparticles and a surface enzymatic reaction. Immunoglobulin E (IgE) was used as a model protein biomarker, which possesses two distinct epitopes for antibody (anti-IgE) and DNA aptamer binding. A surface sandwich assay format was utilized involving the specific adsorption of IgE onto a gold electrode surface that was pre-modified with a monolayer of aptamer–nanoparticle conjugates followed by the specific interaction of alkaline phosphatase (ALP) conjugated anti-IgE. To clearly demonstrate the signal enhancement associated with nanoparticle use, anodic current measurements of the ALP catalyzed oxidation of the enzyme substrate 4-aminophenylphosphate (APP) were also compared with electrode surfaces upon which the aptamer was directly attached. The detection of an unlabelled protein at concentrations as low as 5 fM is a significant improvement compared to conventional electrochemical-based immunoassay approaches and provides a foundation for the practical use and incorporation of nanoparticle-enhanced detection into electrochemical biosensing technologies.

Neural stem cell-based dual suicide gene delivery for metastatic brain tumors

Abstract: In our previous works, we demonstrated that human neural stem cells (NSCs) transduced with the cytosine deaminase (CD) gene showed remarkable ‘bystander killer effect’ on glioma and medulloblastoma cells after administration of the prodrug 5-fluorocytosine (5-FC). In addition, herpes simplex virus thymidine kinase (TK) is a widely studied enzyme used for suicide gene strategies, for which the prodrug is ganciclovir (GCV). To apply this strategy to brain metastasis treatment, we established here a human NSC line (F3.CD-TK) expressing the dual suicide genes CD and TK. We examined whether F3.CD-TK cells intensified the antitumor effect on lung cancer brain metastases. In vitro studies showed that F3.CD-TK cells exerted a marked bystander effect on human lung cancer cells after treatment with 5-FC and GCV. In a novel experimental brain metastases model, intravenously administered F3 cells migrated near lung cancer metastatic lesions, which were induced by the injection of lung cancer cells via the intracarotid artery. More importantly, F3.CD-TK cells in the presence of prodrugs 5-FC and GCV decreased tumor size and considerably prolonged animal survival. The results of the present study indicate that the dual suicide gene–engineered, NSC-based treatment strategy might offer a new promising therapeutic modality for brain metastases.

Parts per trillion detection of Ni(II) ions by nanoparticle-enhanced surface plasmon resonance.

Abstract: This paper demonstrates the development of a novel nanoparticle-enhanced surface plasmon resonance (SPR) sensing platform for the selective and sensitive in situ detection of nickel(II) ions at concentrations as low as 50 parts per trillion (211 pM). An enhancement in selectivity was achieved by designing a surface sandwich assay involving two different ligands each selective toward nickel(II) ions, namely, N-[5-(3'-maleimidopropylamido)-1-carboxypentyl]iminodiacetic acid (NTA) and polyhistidine. Maleimido-modified NTA was first immobilized on an alkanedithiol-modified gold thin film, followed by the sequential adsorption of Ni(II) ions. Next, polyhistidine-functionalized quasispherical gold nanoparticles, designed to enhance the SPR sensitivity, were specifically adsorbed onto surface Ni(II)-NTA complexes. This process was monitored by real-time SPR. The ability to detect Ni(II) ions as low as 50 parts per trillion (ppt) is a remarkable improvement compared to other optical and colorimetric techniques utilizing nanoparticles and is comparable to what can be achieved by state-of-the-art inductively coupled plasma mass spectrometry (ICP-MS). The improved selectivity for Ni(II) ions by the sandwich assay approach was confirmed by comparing measurements involving other divalent cations such as Zn(II), Pb(II), and Cu(II), some of which individually possess binding affinities toward either the NTA or histidine moieties.

Voltammetric Studies of Anion Transfer Reactions Across a Microhole Array-Water/PVC-NPOE Gel Interface

Abstract: Laboratoire d’Electrochimie Physique et Analytique, Station 6, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne, SwitzerlandReceived December 18, 2011, Accepted February 27, 2012Voltammetric characterization of hydrophilic anion transfer processes across a 66 microhole array interfacebetween the water and polyvinylchloride-2-nitrophenyloctylether gel layer is demonstrated. Since the transferof hydrophilic anions including Br

Synthesis and Characterization of H3PO4 Doped Poly(benzimidazole-co-benzoxazole) Membranes for High Temperature Polymer Electrolyte Fuel Cells

Abstract: E-mail: hjkim25@kist.re.krReceived March 27, 2012, Accepted July 11, 2012Poly(benzimidazole-co-benzoxazole)s (PBI-co-PBO) are synthesized by polycondensation reaction with 3,3'-diaminobenzidine, terephthalic acid and 3,3'-dihydroxybenzidine or 4,6-diaminoresorcinol in polyphosphoricacid (PPA). All polymer membranes are prepared by the direct casting method (in-situ fabrication). Theintroduction of benzoxazole units (BO units) into a polymer backbone lowers the basic property and H

Epidemiologic Features of Parainfluenza Virus Type 1, 2 and 3 Infection in Seoul and a Neighboring Area, 2008-2011

Abstract: pes. The most common diagnosis among all PIV subtypes was pneumonia. Lower respiratory tract in- fections constituted the majority (76.3%) of PIV infections. The most common diagnosis of PIV type I and II was croup and that of PIV type III was pneumonia. A difference in seasonal variation be- tween subtypes was observed. PIV I (62.2%) was mainly isolated from July to September while PIV type III (86.8%) was isolated from April to July. Conclusion: Lower respiratory infection was most commonly found in hospitalized patients with PIV infection. Clinical features of PIV infection were sim- ilar those seen in Western PIV reports, with the ex- ception of the seasonal outbreak pattern. (Korean J Clin Microbiol 2012;15:54-59)

High-Density Nanoporous Structures for Enhanced Electrocatalysis

Abstract: A novel method to create a high-density nanopore structure between the neighboring pores of anodic alumina template is developed via applying a simple consecutive three-step anodization process. As a demonstration, the nanostructure comprising more numbers of individually addressable Pd nanorods was utilized to enhance the electrocatalysis of ethanol in alkaline media, which is due to a dramatic increment in surface reactive sites.

Quantitative analysis method using a nanotube having integrated enzymes

Abstract: The present invention relates to a quantitative analysis method which involves analyzing an object using an enzyme, aptamer, antibody, nanotube, and a magnetic bead or a substrate More particularly, a binding aptamer or antibody to be bonded to an analysis object is bonded to a magnetic bead or a substrate, and the resultant structure is placed into a solution to be analyzed, bonded to the analysis object, and separated from the analysis object by magnetic force; another aptamer or antibody to be selectively bonded to the analysis object is bonded to the surface of the nanotube, on which enzymes are integrated, so as to prepare for a quantitative analysis of the analysis object; and the quantitative analysis is performed, through an enzyme reaction, on a composite body which is prepared by binding the resultant structure to the magnetic bead or substrate to which the aptamer or antibody is bonded Thus, a low concentration analysis object can be diagnosed, and difficulties in quantitative analysis according to conventional detection methods can be overcome using the signal-amplification effects of a nanotube having integrated enzymes

Chromosomal Abnormalities in Myelodysplastic Syndrome with Near-tetraploidy: A Case Report

Abstract: eISSN 2093-6338 자들의 결함들이 축적되어서 급성골수성백혈병으로 전환되는 것 으로 여겨지고 있다[2]. 클론성 세포유전학적 이상은 새로(de novo) 발생한 골수형성이 상증후군에서 40%, 이차성 골수형성이상증후군에서는 80%가 발 견된다고 보고되었다[3]. International Prognostic Scoring System (IPSS)에서는 세포유전학적 이상을 급성골수성백혈병의 생존과 예후를 판정해주는 독립적인 인자로 인정하였으며, 그 중에서도 3 가지 이상의 세포유전학적 이상이 존재하는 복잡형 핵형(complex karyotype)은 골수형성이상증후군 중에서도 나쁜 예후를 시 사하는 소견이라고 정의하였다[4]. 여러 염색체 이상 중에서 50개 이상의 염색체수를 보이는 중과 이배수체증(massive hyperdiploidy)과 네배수체증(tetraploidy)은 골수성 종양에서 드물게 관찰되는 세포유전학적 이상으로 알려져 있으며[5], 이러한 세포유전학적 이상은 골수형성이상증후군에서 나쁜 예후와 관련이 있다고 하나 아직까지 보고된 예가 적어 임상 적인 의미가 확실하지 않다[5-9]. 저자들은 골수형성이상증후군을 진단받고 염색체 검사에서 근네배수체증(near-tetraploidy)을 보인 환자를 경험하여 문헌 고찰과 함께 보고하는 바이다. 서 론