Biomedical subjects

Jong-Won Park

Publications and source records attributed to Jong-Won Park.

At least 19 recordsLinked to original sources

PubMed2006

Quartz crystal microbalance immunosensors for environmental monitoring.

This paper presents discussion of quartz crystal microbalance (QCM) immunosensors for environmental monitoring. Factors limiting the practical application of antibodies to analytical problems are also presented. Among several candidates for the QCM immunosensor device, selected QCM devices and oscillating circuits were tested thoroughly and developed to obtain highly stable and sensitive frequency signals. The biointerface of QCM immunosensor was designed and controlled to immobilize antibody on the QCM surface, to reduce non-specific binding and to suppress denaturation of immobilizing antibody by self-assembled monolayer technique and artificial phospholipid (2-methacryloyloxyethyl phosphorylcholine (MPC)) polymer. MPC polymer as a antibody-stabilizing reagent was added to reduce non-specific binding of the antigen solution and stabilize the immunologic activity of the antibody-immobilized QCM. In addition, it provides examples for detection and quantitation of environmental samples using QCM immunosensors. The analytical results for fly ash extracted samples of dioxins using the QCM immunosensor indicated a good relationship with GC/MS methods. The integrating protocols of the competitive immunoassay and signal-enhancing step are for detecting low molecular analytes with extremely low detection limits using an QCM immunosensor. Furthermore, its detect limitation was extended from 0.1 to 0.01 ng/ml by the signal-enhancing step when the anti-bisphenol-A antibody conjugated MPC polymeric nanoparticles was used. The QCM immunosensor method has demonstrated its effectiveness as an alternative screening method for environmental monitoring because these results were compared with results obtained through environmental monitoring methods such as ELISA and GC/MS.

Biosensing Techniques↗

PubMed2006

Dioxin immunosensor using anti-2,3,7,8-TCDD antibody which was produced with mono 6-(2,3,6,7-tetrachloroxanthene-9-ylidene) hexyl succinate as a hapten.

To detect dioxin using a quartz crystal microbalance (QCM) immunosensor, anti-2,3,7,8-tetrachloro-p-dibenzodioxin (TCDD) monoclonal antibodies (MAbs) were produced as types of IgG1 and IgM, with mono 6-(2,3,6,7-tetrachloroxanthene-9-ylidene) hexyl succinate (as a hapten) conjugated with bovine serum albumin (dioxin-BSA). Furthermore, ScFv was generated from hybridoma-producing IgG1 MAb. Among these antibodies, ScFv showed excellent capability for dioxin detection using QCM immunosensors.

Animals↗

PubMed2006

The cysteine-histidine-rich region of the movement protein of Cucumber mosaic virus contributes to plasmodesmal targeting, zinc binding and pathogenesis.

Viral movement proteins (MPs) are central to the establishment of viral pathogenesis, and yet relatively little is understood about the structural and functional aspects of MPs or about the host factors on which they depend. Through chemical mutagenesis of transgenic Arabidopsis expressing Cucumber mosaic virus (CMV) MP fused with the green fluorescent protein, we have studied the function of a central region of the MP, defined by a number of conserved cysteine and histidine residues (Cys-His-rich region), which potentially functions as a zinc-binding domain. Transient expression of mutant MPs identified through an in planta screen for altered MP function or constructed with altered putative zinc ligands through site-directed mutagenesis showed that mutations in the Cys-His-rich region affected localization to and trafficking through plasmodesmata. In vitro zinc-binding analysis revealed that wild type (wt) CMV MP had the ability to bind zinc and that movement-defective mutants bound zinc with less affinity than wt MP. Furthermore, a correlation between the association of the MP with plasmodesmata and virus pathogenesis was shown. We discuss roles of the Cys-His region in biochemical and biological functions of the MP during virus movement.

Amino Acid Sequence↗

PubMed2006

A new eriophyid mite-borne membrane-enveloped virus-like complex isolated from plants.

A decade ago, a new mite-transmitted disease was described on wheat (Triticum aesativum) and maize (Zea mays) that due to its geographical location was referred to as High Plains Disease (HPD). To determine the etiology, we established colonies of HPD pathogen-transmitting eriophyid wheat curl mites (Aceria tosichella) on wheat plants for maintenance of a continuous source of infected material. Analyses of nucleic acid obtained from infected plants showed the presence of HPD-specific RNAs ranging from 1.5 to 8 kilobases, but comparisons between the sequence of cDNAs and the databases did not reveal any clear identity with known viruses. We demonstrate that a diagnostic HPD-specific 32-kDa protein that accumulates in plants is encoded by a small RNA species (RNA-s). Upon infestation of upper wheat parts with viruliferous mites, the RNA-s encoded protein becomes detectable within a few days in the roots, indicative of an effective virus-like mode of transport. Membranous particles, resembling those observed in thin sections of infected plants, were isolated and shown to envelope a thread-like ribonucleoprotein complex containing the RNA-s encoded 32-kDa protein. This complex was associated with single-stranded (-)-sense RNAs, whereas free (+)-sense RNA was only detected in total RNA of infected plants. Based on the collective properties, we conclude that HPD is caused by a newly emerged mite-borne virus, for which we propose the name Maize red stripe virus (MRStV).

Animals↗

PubMed2006

Plasma eosinophil cationic protein, interleukin-5, and ECP/Eo count ratio in patients with various eosinophilic diseases.

Hypereosinophilia is associated with clonal disorders, reactive conditions, and rarely with idiopathic hypereosinophilic syndrome (IHES). We investigated whether measurement of eosinophilic activity using the plasma eosinophil cationic protein (ECP) level, interleukin-5 (IL-5) level, and the ratio of eosinophilic cationic protein/eosinophil count (ECP/Eo) could improve the early differentiation among various eosinophilic diseases: IHES (n = 9), clonal disorder (n = 35), reactive eosinophilia with malignancy (n = 30), and reactive eosinophilia with inflammation (n = 46). The 120 eosinophilic patients had higher plasma ECP and IL-5 levels than the non-eosinophilic control group (p <0.05). The 9 patients with IHES had significantly higher plasma ECP and IL-5 levels than patients with other eosinophilic diseases (p <0.05). The plasma levels of ECP and the ECP/Eo ratio were higher in patients with non-haematologic malignancy than in those with other reactive eosinophilias (p <0.05). This study shows that levels of plasma ECP, IL-5, and ECP/Eo ratio may assist in the clinical differentiation of various eosinophilic diseases.

Biomarkers↗

PubMed2005

Piezoelectric immunosensor for bisphenol A based on signal enhancing step with 2-methacrolyloxyethyl phosphorylcholine polymeric nanoparticle.

An immunoassay in which BPA competed with a BPA-horseradish peroxidase conjugate for binding to anti-BPA antibodies, coupled to a piezoelectric (PZ) immunosensor, was able to detect 0.1 ng mL(-1) BPA. To enhance the sensitivity of the assay, we tested nanoparticles approximately 200 nm in diameter, coupled to anti-BPA antibodies, to increase the mass change on the surface of the immunosensor and thereby increase the frequency shift detected. This second step, using nanoparticles coated with anti-BPA antibodies, improved the sensitivity of the assay by approximately eight times at BPA concentrations below 10 ng mL(-1). Field emission-scanning electron microscopy (FE-SEM) showed that polymeric 2-methacrolyloxyethyl phosphorylcholine (MPC) nanoparticles coupled to antibodies remained monodisperse on the surface of the immunosensor and therefore produced stable signals in the immunosensors. Since the frequency shift detected in the assay mainly originated from the mass change on the surface of the PZ crystal, the colloidal stability of the antibody-conjugated particles used in the enhancement step played an extremely important role in achieving a stable and highly sensitive signal.

Antibodies, Monoclonal↗

PubMed2005

Automatic navigation path generation based on two-phase adaptive region-growing algorithm for virtual angioscopy.

In this paper, we propose a fast and automated navigation path generation algorithm to visualize inside of carotid artery using MR angiography images. The carotid artery is one of the body regions not accessible by real optical probe but can be visualized with virtual endoscopy. By applying two-phase adaptive region-growing algorithm, the carotid artery segmentation is started at the initial seed, which is located on the initially thresholded binary image. This segmentation algorithm automatically detects the branch position with stack feature. Combining with a priori knowledge of anatomic structure of carotid artery, the detected branch position is used to separate the carotid artery into internal carotid artery and external carotid artery. A fly-through path is determined to automatically move the virtual camera based on the intersecting coordinates of two bisectors on the circumscribed quadrangle of segmented carotid artery. In consideration of the interactive rendering speed and the usability of standard graphic hardware, endoscopic view of carotid artery is generated by using surface rendering algorithm with perspective projection method. In addition, the endoscopic view is provided with ray casting algorithm for off-line navigation of carotid artery. Experiments have been conducted on both mathematical phantom and clinical data sets. This algorithm is more effective than key-framing and topological thinning method in terms of automated features and computing time. This algorithm is also applicable to generate the centerline of renal artery, coronary artery, and airway tree which has tree-like cylinder shape of organ structures in the medical imagery.

Algorithms↗

PubMed2005

Quartz crystal microbalance immunosensor for highly sensitive 2,3,7,8-tetrachlorodibenzo-p-dioxin detection in fly ash from municipal solid waste incinerators.

A quartz crystal microbalance (QCM) immunosensor was developed for the detection of 2,3,7,8-tetrachlorodibenzo-p-dioxins (TCDD) in environmental pollutants. An anti-TCDD antibody was immobilized on the gold surface of the QCM via chemical coupling, and its immunologic activity was then maintained by treatment with an artificial stabilizing reagent such as poly(2-methacryloyloxyethyl phosphorylcholine-co-n-butyl methacrylate). A competitive immunoreaction with TCDD conjugated ovalbumin (TCDD-ovalbumin) was used to detect TCDD. A calibration curve was obtained through the competitive immunoreaction, and linearity was shown from 100 ng mL(-1) to 0.1 ng mL(-1). Also, the cross-reactivities of the anti-TCDD monoclonal antibody were thoroughly evaluated with several TCDD derivatives. The relationships between GC-MS, ELISA, and QCM were compared using fly ash samples from a municipal solid waste, which were prepared using an accelerated solvent extractor. For 23 samples, the experimental relationship between the TCDD concentration by QCM vs. the TCDD concentration by ELISA was y= 1.07x + 2.70, r= 0.99, and the TCDD concentration by QCM vs. the toxic equivalent quantity (TEQ) value by GC-MS was y= 2.46x - 14.98, r= 0.89.

Air Pollutants↗

PubMed2005

Visualization of the internal carotid artery using MRA images.

A virtual angioscopy system is implemented to visualize the inside of the internal carotid artery (ICA) for qualitative assessment of carotid artery stenosis using magnetic resonance angiography (MRA) images. The carotid artery is one of the body regions not accessible by real optical endoscopy but can be visualized with virtual endoscopy. In order to visualize the carotid artery, it is segmented using the region-growing algorithm after locating the initial seed on the presegmented binary image. The ICA is separated from the external carotid artery (ECA) using a priori knowledge of the anatomic structure after bifurcation. A fly-through path is computed based on the medial axis transform (MAT) to automatically move the virtual camera from the common carotid artery (CCA) to the ICA. Considering interactive rendering speed and usability of standard graphic hardware, the surface-rendering algorithm with the perspective projection method is used to generate an endoscopic view of the ICA. In addition, the endoscopic view with the raycasting algorithm is provided for off-line navigation of the carotid artery. Virtual angioscopy is highly recommended as a diagnostic tool for identifying the specific location of the stenosis and for analyzing the stenosis qualitatively. The virtual angioscopy system for carotid artery will benefit radiological diagnostics, medical education, surgical planning and postoperative assessment.

Adult↗

PubMed2005

The effect of low glucose degradation product dialysis solution on epithelial-to-mesenchymal transition in continuous ambulatory peritoneal dialysis patients.

BACKGROUND: Human peritoneal mesothelial cells (HPMCs) undergo a transition from an epithelial phenotype to a mesenchymal phenotype (EMT) during peritoneal dialysis (PD). That transition may be directly related to failure of peritoneal membrane function. OBJECTIVE: In a randomized prospective controlled study, we investigated the effect of low glucose degradation product (GDP) dialysis solution on the transition of HPMCs. METHODS: Among new continuous ambulatory PD patients, 60 patients completed a 12-month protocol (low-GDP solution group, n = 32; high-GDP solution group, n = 28). At the 1st, 6th, and 12th months, HPMCs drained from overnight effluent were cultured on T25. When they had nearly reached confluence, cell scores were measured blindly by the same person (score 1 = cobblestone-shaped HPMCs, score 2 = mixed, score 3 = fibroblast dominant). Cell scores and clinical indices, including peritoneal markers, were compared between the low-GDP and high-GDP groups at the 1st, 6th, and 12th months. The factors associated with EMT were analyzed with generalized estimating equations using STATA 7.0 (STATA Corp., College Station, Texas, USA). In addition, vimentin and cytokeratin 8/18 stains were used to verify EMT in cultured cells and peritoneal specimens in some patients. RESULTS: (1) The low-GOP group showed higher dialysate cancer antigen 125 levels from the 1st to 12th months (55.4 +/- 24.8 vs 8.8 +/- 1.7, 56.7 +/- 28.1 vs 22.1 +/- 11.3, and 54.2 +/- 28.2 vs 24.6 +/- 16.5 U/mL, at the 1st, 6th, and 12th months, respectively; all p = 0.000). (2) The low-GOP group showed lower cell scores at the 1st, 6th, and 12th months (1.22, 1.22, and 1.56 vs 1.61, 1.75, and 2.14; p < 0.05, p < 0.01, and p < 0.01, respectively). (3) At the 12th month, the number of fibroblast-dominant cultures (score 3) was significantly lower in the low-GOP group [4/32 (12.5%) patients vs 14/28 (50%), p < 0.05]. (4) Both cobblestone-shaped HPMCs and fibroblastoid cells were positively stained with cytokeratin and vimentin. (5) There were many cytokeratin- and vimentin-positive cells in the submesothelial area in the peritoneal biopsy specimens. (6) The consistent factor associated with EMT was only high-GOP solution (60 patients, n = 178, beta coefficient 0.312, p = 0.000; 46 patients, n = 137, beta coef: 0.228, p = 0.000) and not numbers of peritonitis episodes, duration of angiotensin-converting enzyme inhibitor and/or angiotensin receptor blocker medication, or diabetes. CONCLUSION: Low-GDP solution showed beneficial effects such as rapid remesothelialization and less EMT in the peritoneum with time on PD.

Adult↗

PubMed2004

Evaluation of a high-affinity QCM immunosensor using antibody fragmentation and 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer.

This study evaluated construction of a highly affinitive quartz crystal microbalance (QCM) immunosensor using anti-C-reactive protein (CRP) antibody and its fragments for CRP detection. Three types of antibody were immobilized on the surface of a QCM via covalent-bounding. Then affinity was evaluated through antigen-antibody binding between CRP and its antibody. Affinity between antigen-antibody was shown to be highest when anti-CRP F(ab')2-IgG antibody (70 microg/mL) was immobilized on the QCM. In case of anti-CRP F(ab')2-IgG antibody, affinity which was attributable to antigen-antibody binding was almost twice that of anti-CRP IgG antibody, which is used conventionally for QCM immunosensors. In addition, when it was treated with 2-methacryloyloxyethyl phosphorylcholine-co-n-butyl methacrylate, so-called MPC polymer, highly affinitive and selective immunosensing for CRP was achieved without non-specific binding from plasma proteins in human serum. When anti-CRP F(ab')2-IgG antibody was immobilized on the QCM, the detection limit and the linearity of CRP calibration curve were achieved at concentrations from 0.001 to 100 microg/dL even during investigation in serum samples. Experimental results verified the successful construction of a highly affinitive and selective QCM-immunosensor which was modified with anti-CRP F(ab')2-IgG antibody and MPC polymer.

Antigen-Antibody Complex↗

PubMed2004

The multifunctional plant viral suppressor of gene silencing P19 interacts with itself and an RNA binding host protein.

Tomato bushy stunt virus (TBSV) is an RNA plant virus encoding a protein of approximately 19 kDa (P19) that is involved in various activities important for pathogenicity, including virus transport and suppression of gene silencing. In this study, we provide evidence in vivo and in vitro that P19 specifically interacts with itself to predominantly form dimers, and with a novel host protein, Hin19. Hin19 has a high degree of similarity with a class of RNA-binding proteins of which many are involved in RNA processing. The binding of P19 to itself and to Hin19 both depend on a structurally important central region of P19 that was previously shown critical for its biological function in plants. Our findings provide evidence for a model in which virus spread through suppression of defense-related gene silencing involves the formation of a complex that includes P19 dimers and a newly identified host RNA-binding protein.

Amino Acid Sequence↗

PubMed2004

Regional outbreak of mumps due to genotype H in Korea in 1999.

Serological and virological studies were carried out of a mumps outbreak which occurred in one region, Yoeju County, Southeast of Seoul in Korea from September to December, 1999. Sera from 736 children at 8-13 years of age of patients with mumps and healthy children were tested for mumps-specific antibodies by enzyme immunoassay. The overall IgM positive rate was 7.6% (56/736), compared with 69.8% (514/736) for IgG. Of the 49 children with both IgG and IgM, 32 were also confirmed by both clinical and serological diagnosis. IgM antibodies were detected even in the samples collected up to 3 months after the onset of symptoms. Although 436 children had been vaccinated before the outbreak, 27 (6.2%) were found to be IgM positive, particularly 6 (4.4%) of 136 were positive serologically despite a second-dose vaccinees. Sequence analysis of the small hydrophobic (SH) gene of 4 mumps viruses isolated from 42 saliva specimens revealed that these were related to the genotype H, but distinguishable from European strains. This is the first study on the outbreak due to mumps virus genotype H and provides information to assess the understanding of recent outbreaks of mumps in Korea.

Adolescent↗

PubMed2004

Computerized quantification of carotid artery stenosis using MRA axial images.

Currently, the North American symptomatic carotid endarterectomy trial, European carotid surgery trial, and common carotid method are used to measure the carotid stenosis for determining candidates for carotid endarterectomy using the projection angiography from different modalities such as digital subtraction angiography, rotational angiography, computed tomography angiography and magnetic resonance angiography. A new computerized carotid stenosis measuring system was developed using MR angiography axial image to overcome the drawbacks of conventional carotid stenosis measuring methods, to reduce the variability of inter-observer and intra-observer. The gray-level thresholding is one of the most popular and efficient methods for image segmentation. We segmented the carotid artery and lumen from three-dimensional time-of-flight MRA axial images using gray-level thresholding technique. Using the measured intima-media thickness value of common carotid artery for each case, we separated carotid artery wall from the segmented carotid artery region. After that, the regions of segmented carotid without artery wall were divided into region of blood flow and plaque. The calculation of carotid stenosis degree was performed as follows: carotid stenosis grading = (area measure of plaque/area measure of blood flow region and plaque) * 100%. No previous study has developed the carotid stenosis measuring method using MRA axial image. The new computerized stenosis measuring system has advantage over conventional caliper measuring methods; it will not only greatly increase the speed of stenosis measuring but also reduce the variability between readers. It should also reduce the variability between different institutions.

Adult↗

PubMed2003

Conventional detection method of fibrinogen and fibrin degradation products using latex piezoelectric immunoassay.

We developed a conventional immunosensor for fibrinogen and fibrin degradation products (FDP) to combine a quartz crystal microbalance (QCM) with the agglutination reaction of immunized latex beads. FDP induced an immunoreaction due to anti-FDP antibody immobilized latex particles. We successfully measured FDP concentration of in human serum within 10 min by QCM method. The detection range of QCM immunosensor is covered with screening concentration of FDP in serum (<10 microg/ml of FDP). The time course of latex agglutination obtained from QCM immunosensor is synchronized to that of latex photometric immunoassay. SEM was used to observe the surface of QCM that applied FDP serum. The size of latex particles agglutinated on the QCM electrode increased concomitant with FDP concentration. Frequency shift on immunoreaction explains the increased adsorption amount of agglutinated latex on QCM.

Biosensing Techniques↗

PubMed2003

Conventional detection of 2,4-dinitrophenol using quartz crystal microbalance.

We present conventional detection of 2,4-dinitrophenol (DNP) for using the competitive reaction between DNP and DNP-conjugated albumin onto DNP antibody immobilized quartz crystal microbalance (QCM). This QCM method allows detection of DNP concentration in the range of 0.01 to 100 ng/ml; linear correlation obtains DNP concentration from 1 to 100 ng/ml.

2,4-Dinitrophenol↗

PubMed2003

Stabilizing effect of artificial stabilizers for binding activity of QCM immunosensors.

We compare stabilizing effects of artificial and natural stabilizers for maintenance of binding activity of immobilized antibody on the gold surface of quartz crystal microbalance (QCM). Binding activity between immobilizing antibody and specific antigen was measured and considered as a calculated frequency shift with QCM-immunosensor after temperature increasing and long-term storage. According to the experimental results, one stabilizer among eight samples shows the best stabilizing effect for QCM-immunosensor.

Adsorption↗

PubMed2002

Tombusvirus P19-mediated suppression of virus-induced gene silencing is controlled by genetic and dosage features that influence pathogenicity.

The p19 protein (P19) of Tomato bushy stunt virus (TBSV) is a pathogenicity determinant with host-dependent effects on virus spread and symptom induction. In addition, results in this study confirm that Potato virus X-mediated delivery of P19 suppresses posttranscriptional gene silencing (PTGS). To study the relevance of this activity for TBSV biology, we evaluated whether TBSV activates virus-induced gene silencing (VIGS) and if this process is suppressed by P19. TBSV vectors with the green fluorescent protein (GFP) gene, either active or inactive for P19 expression, were inoculated onto GFP-transgenic Nicotiana benthamiana plants. In the absence of P19 expression, VIGS was activated, as evidenced by the disappearance of GFP mRNA and green fluorescence. Coexpression of GFP and P19 from the TBSV vector suppressed VIGS, except in the newly emerging leaves. The suppressor activity required a central P19 region that is also known to be essential for host-dependent virus spread and symptom induction. Defective interfering RNAs (DIs) that contained the 3' end of the GFP gene induced silencing very effectively. The concomitant DI-instigated reduction in P19 accumulation failed to suppress this process, analogous to the known P19 dosage effects for other biological activities. In conclusion, (i) TBSV and its DIs are very effective inducers of VIGS, (ii) P19 is a strong suppressor of PTGS, (iii) P19 is a moderate suppressor of VIGS, and (iv) the suppressor activity is influenced by genetic and dosage features that are also important for P19-associated pathogenesis.

Gene Expression Regulation, Viral↗