Publications by authors named "Ji Woong Kim"

55 Publications

Cell Surface GRP94 as a Novel Emerging Therapeutic Target for Monoclonal Antibody Cancer Therapy.

Cells 2021 Mar 17;10(3). Epub 2021 Mar 17.

Biopharmaceutical Chemistry Major, School of Applied Chemistry, Kookmin University, Seoul 02707, Korea.

Glucose-regulated protein 94 (GRP94) is an endoplasmic reticulum (ER)-resident member of the heat shock protein 90 (HSP90) family. In physiological conditions, it plays a vital role in regulating biological functions, including chaperoning cellular proteins in the ER lumen, maintaining calcium homeostasis, and modulating immune system function. Recently, several reports have shown the functional role and clinical relevance of GRP94 overexpression in the progression and metastasis of several cancers. Therefore, the current review highlights GRP94's physiological and pathophysiological roles in normal and cancer cells. Additionally, the unmet medical needs of small chemical inhibitors and the current development status of monoclonal antibodies specifically targeting GRP94 will be discussed to emphasize the importance of cell surface GRP94 as an emerging therapeutic target in monoclonal antibody therapy for cancer.
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http://dx.doi.org/10.3390/cells10030670DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8002708PMC
March 2021

Fabrication of plasmonic arrays of nanodisks and nanotriangles by nanotip indentation lithography and their optical properties.

Nanoscale 2021 Mar;13(8):4475-4484

Interdisciplinary Materials Measurement Institute, Korea Research Institute of Standards and Science, Daejeon 34113, South Korea.

Fabrication of plasmonic nanostructures in a precise and reliable manner is a topic of huge interest because their structural details significantly affect their plasmonic properties. Herein, we present nanotip indentation lithography (NTIL) based on atomic force microscopy (AFM) indentation for the patterning of plasmonic nanostructures with precisely controlled size and shape. The size of the nanostructures is controlled by varying the indentation force of AFM tips into the mask polymer; while their shapes are determined to be nanodisks (NDs) or nanotriangles (NTs) depending on the shapes of the AFM tip apex. The localized surface plasmon resonance of the NDs is tailored to cover most of the visible-wavelength regime by controlling their size. The NTs show distinct polarization-dependent plasmon modes consistent with full-wave optical simulations. For the demonstration of the light-matter interaction control capability of NTIL nanostructures, we show that photoluminescence enhancement from MoS2 layers can be deliberately controlled by tuning the size of the nanostructures. Our results pave the way for the AFM-indentation-based fabrication of plasmonic nanostructures with a highly precise size and shape controllability and reproducibility.
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http://dx.doi.org/10.1039/d0nr08398dDOI Listing
March 2021

Metabolic Engineering of Extremophilic Bacterium for the Production of the Novel Carotenoid Deinoxanthin.

Microorganisms 2020 Dec 25;9(1). Epub 2020 Dec 25.

School of Environmental Engineering, University of Seoul, Seoul 02504, Korea.

Deinoxanthin, a xanthophyll derived from species, is a unique organic compound that provides greater antioxidant effects compared to other carotenoids due to its superior scavenging activity against singlet oxygen and hydrogen peroxide. Therefore, it has attracted significant attention as a next-generation organic compound that has great potential as a natural ingredient in a food supplements. Although the microbial identification of deinoxanthin has been identified, mass production has not yet been achieved. Here, we report, for the first time, the development of an engineered extremophilic microorganism, strain R1, that is capable of producing deinoxanthin through rational metabolic engineering and process optimization. The genes and were first introduced into the genome to reinforce the metabolic flux towards deinoxanthin. The optimal temperature was then identified through a comparative analysis of the mRNA expression of the two genes, while the carbon source was further optimized to increase deinoxanthin production. The final engineered strain R1 was able to produce 394 ± 17.6 mg/L (102 ± 11.1 mg/g DCW) of deinoxanthin with a yield of 40.4 ± 1.2 mg/g sucrose and a productivity of 8.4 ± 0.2 mg/L/h from 10 g/L of sucrose. The final engineered strain and the strategies developed in the present study can act as the foundation for the industrial application of extremophilic microorganisms.
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http://dx.doi.org/10.3390/microorganisms9010044DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7823818PMC
December 2020

Time-Dependent Anti-Demineralization Effect of Silver Diamine Fluoride.

Children (Basel) 2020 Nov 24;7(12). Epub 2020 Nov 24.

Department of Pediatric Dentistry, School of Dentistry, Chosun University, Gwangju 61452, Korea.

This study compared the demineralization resistance of teeth treated with silver diamine fluoride (SDF) to that treated with fluoride varnish. A total of 105 healthy bovine incisors were divided into control, fluoride varnish, and SDF groups. The enamel surface density change was then measured by micro-computed tomography (micro-CT) at three depths. The demineralized zone volume was measured on 3D micro-CT images to evaluate the total demineralization rate. The enamel surface morphology was assessed by scanning electron microscope. The enamel density had continuously decreased while demineralization increased in the control and fluoride varnish groups. The enamel density had increased in the SDF group till the 7th day of demineralization treatment and decreased thereafter. However, the decrease in the SDF group was less severe than that in the other groups ( < 0.05). The demineralized enamel volume had increased through treatment and was the highest in the control group, followed by the fluoride varnish and SDF group. The enamel surface morphology was the roughest and most irregular in the control group, followed by the fluoride varnish group and SDF groups.
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http://dx.doi.org/10.3390/children7120251DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7760551PMC
November 2020

Physiological and Biochemical Changes in Sugar Beet Seedlings to Confer Stress Adaptability under Drought Condition.

Plants (Basel) 2020 Nov 7;9(11). Epub 2020 Nov 7.

Department of Bio-Health Convergence, Kangwon National University, Chuncheon 24341, Korea.

The present study was conducted to examine the adaptability of 11 sugar beet cultivars grown under drought stress in the controlled glasshouse. The treatment was initiated on 30-day-old sugar beet plants where drought stress was made withholding water supply for consecutive 10 days while control was done with providing water as per requirement. It was observed that drought stress expressively reduced plant growth, photosynthetic pigments, and photosynthetic quantum yield in all the cultivars but comparative better results were observed in S1 (MAXIMELLA), S2 (HELENIKA), S6 (RECODDINA), S8 (SV2347), and S11 (BSRI Sugarbeet 2) cultivars. Besides, osmolytes like proline, glycine betaine, total soluble carbohydrate, total soluble sugar, total polyphenol, total flavonoid, and DPPH free radical scavenging activity were remarkably increased under drought condition in MAXIMELLA, HELENIKA, TERRANOVA, GREGOIA, SV2348, and BSRI Sugar beet 2 cultivars. In contrast, activities of enzymes like superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) were significantly decreased in all, while the cultivars SV2347, BSRI Sugar beet 1 and BSRI Sugar beet 2 were found with increased ascorbate peroxidase (APX) activity under drought condition. In parallel, polyphenol oxidase (PPO) was increased in all cultivars except HELENIKA. Overall, the cultivars HELENIKA, RECODDINA, GREGOIA, SV2347, SV2348, BSRI Sugar beet 1, and BSRI Sugar beet 2 were found best fitted to the given drought condition. These findings would help further for the improvement of stress adaptive sugar beet cultivars development in the breeding program for drought-prone regions.
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http://dx.doi.org/10.3390/plants9111511DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7695173PMC
November 2020

Feature optimization method for machine learning-based diagnosis of schizophrenia using magnetoencephalography.

J Neurosci Methods 2020 05 19;338:108688. Epub 2020 Mar 19.

Department of Psychiatry, Konyang University College of Medicine, Konyang University Hospital, Daejeon, Republic of Korea. Electronic address:

Background: When many features and a small number of clinical data exist, previous studies have used a few top-ranked features from the Fisher's discriminant ratio (FDR) for feature selection. However, there are many similarities between selected features. New method: To reduce the redundant features, we applied a technique employing FDR in conjunction with feature correlation. We performed an attention network test on schizophrenic patients and normal subjects with a 152-channel magnetoencephalograph. P300m amplitudes of event-related fields (ERFs) were used as features at the sensor level and P300m amplitudes of ERFs for 500 nodes on the cortex surface were used as features at the source level. Features were ranked using FDR criterion and cross-correlation measure, and then the highest ranked 10 features were selected and an exhaustive search was used to find combination having the maximum accuracy.

Results: At the sensor level, we found a single channel of the occipital region that distinguished the two groups with an accuracy of 89.7 %. At source level, we obtained an accuracy of 96.2 % using two features, the left superior frontal region and the left inferior temporal region.

Comparison With Existing Method: At source level, we obtained a higher accuracy than traditional method using only FDR criterion (accuracy = 88.5 %). We used only the P300 m amplitude (not latency) on a single channel and two brain regions at a fairly high rate.
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http://dx.doi.org/10.1016/j.jneumeth.2020.108688DOI Listing
May 2020

Artificial intelligence, robotics and eye surgery: are we overfitted?

Int J Retina Vitreous 2019 16;5:52. Epub 2019 Dec 16.

Wilmer Eye Institute, Johns Hopkins Hospital, Baltimore, MD 21287 USA.

Eye surgery, specifically retinal micro-surgery involves sensory and motor skill that approaches human boundaries and physiological limits for steadiness, accuracy, and the ability to detect the small forces involved. Despite assumptions as to the benefit of robots in surgery and also despite great development effort, numerous challenges to the full development and adoption of robotic assistance in surgical ophthalmology, remain. Historically, the first in-human-robot-assisted retinal surgery occurred nearly 30 years after the first experimental papers on the subject. Similarly, artificial intelligence emerged decades ago and it is only now being more fully realized in ophthalmology. The delay between conception and application has in part been due to the necessary technological advances required to implement new processing strategies. Chief among these has been the better matched processing power of specialty graphics processing units for machine learning. Transcending the classic concept of robots performing repetitive tasks, artificial intelligence and machine learning are related concepts that has proven their abilities to design concepts and solve problems. The implication of such abilities being that future machines may further intrude on the domain of heretofore "human-reserved" tasks. Although the potential of artificial intelligence/machine learning is profound, present marketing promises and hype exceeds its stage of development, analogous to the seventieth century mathematical "boom" with algebra. Nevertheless robotic systems augmented by machine learning may eventually improve robot-assisted retinal surgery and could potentially transform the discipline. This commentary analyzes advances in retinal robotic surgery, its current drawbacks and limitations, and the potential role of artificial intelligence in robotic retinal surgery.
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http://dx.doi.org/10.1186/s40942-019-0202-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6912992PMC
December 2019

Antagonizing Effects of DC. Extract against Benzo[a]pyrene-Induced Damage to Human Keratinocytes.

Oxid Med Cell Longev 2019 5;2019:2386163. Epub 2019 Nov 5.

Molecular Dermatology Laboratory and Biocosmetics Research Center, Department of Integrative Biotechnology, College of Biotechnology and Bioengineering, Sungkyunkwan University, Suwon City 16419, Gyunggi Do, Republic of Korea.

. Benzo[a]pyrene (B[a]P), a polycyclic aromatic hydrocarbon present in the atmosphere, has cytotoxic and carcinogenic effects. There have been no reports to demonstrate involvement of DC. extract (CAE) in B[a]P-induced effects. This study was conducted to investigate the effect of CAE on B[a]P-induced effects and to elucidate its mechanism of action in HaCaT human keratinocytes. CAE inhibited aryl hydrocarbon receptor (AhR) signaling by decreasing both XRE reporter activity and expression of cytochrome P450 1A1 (CYP1A1) induced by B[a]P treatment in HaCaT cells. We also found that B[a]P-induced nuclear translocation of AhR and production of reactive oxygen species (ROS) and proinflammatory cytokines were attenuated by CAE treatment. CAE treatment suppressed B[a]P-induced phosphorylation of Src (Tyr416). In addition, dasatinib, a Src inhibitor, also inhibited B[a]P-induced nuclear translocation of AhR, similar to CAE treatment. In addition, CAE activated antioxidant response element (ARE) signaling by increasing ARE luciferase reporter activity and expression of ARE-dependent genes such as nuclear factor (erythroid-derived 2)-like 2 (Nrf2), NAD(P)H dehydrogenase [quinone] 1 (NQO1), and heme oxygenase-1 (HO-1). Nuclear translocation of Nrf2 by CAE was demonstrated by Western blot analysis and immunocytochemistry. The effects of CAE on ARE signaling were attenuated by knockdown of the Nrf2 gene. Inhibition of AhR signaling and activation of antioxidant activity by CAE operated in a reciprocally independent manner as evidenced by AhR and Nrf2 siRNA experiments. These findings indicate that CAE exerts protective effects against B[a]P by inhibiting AhR signaling and activating Nrf2-mediated signaling, suggesting its potential in protection from harmful B[a]P-containing pollutants.
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http://dx.doi.org/10.1155/2019/2386163DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6925742PMC
June 2020

Antibody-Based Targeting of Cell Surface GRP94 Specifically Inhibits Cetuximab-Resistant Colorectal Cancer Growth.

Biomolecules 2019 11 1;9(11). Epub 2019 Nov 1.

Biopharmaceutical Chemistry Major, School of Applied Chemistry, Kookmin University, Seoul 02707, Korea.

Colorectal cancer (CRC) is one of the leading causes of cancer death worldwide. Cetuximab, a human/mouse chimeric monoclonal antibody, is effective in a limited number of CRC patients because of cetuximab resistance. This study aimed to identify novel therapeutic targets in cetuximab-resistant CRC in order to improve clinical outcomes. Through phage display technology, we isolated a fully human antibody strongly binding to the cetuximab-resistant HCT116 cell surface and identified the target antigen as glucose-regulated protein 94 (GRP94) using proteomic analysis. Short interfering RNA-mediated GRP94 knockdown showed that GRP94 plays a key role in HCT116 cell growth. In vitro functional studies revealed that the GRP94-blocking antibody we developed strongly inhibits the growth of various cetuximab-resistant CRC cell lines. We also demonstrated that GRP94 immunoglobulin G monotherapy significantly reduces HCT116 cell growth more potently compared to cetuximab, without severe toxicity in vivo. Therefore, cell surface GRP94 might be a potential novel therapeutic target in cetuximab-resistant CRC, and antibody-based targeting of GRP94 might be an effective strategy to suppress GRP94-expressing cetuximab-resistant CRC.
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http://dx.doi.org/10.3390/biom9110681DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6920916PMC
November 2019

CFD analysis of the flow structure in a monkey upper airway validated by PIV experiments.

Respir Physiol Neurobiol 2020 01 20;271:103304. Epub 2019 Sep 20.

Faculty of Engineering Sciences, Kyushu University, Japan.

Inhalation exposure to airborne contaminants has adverse effects on humans; however, related research is typically conducted using in vivo/in vitro tests on animals. Extrapolating the test results is complicated by anatomical and physiological differences between animals and humans and a lack of understanding of the transport mechanism inside their respective respiratory tracts. This study determined the detailed air-flow structure in the upper airway of a monkey. A steady computational fluid dynamics simulation, which was validated by previous particle image velocimetry measurements, was adopted for flow rates of 4 L/min and 10 L/min to analyze the flow structure from the nasal/oral cavities to the trachea region in a monkey airway model. The low Reynolds number type k-ε model provided a reasonably accurate prediction of the airflow in a monkey upper airway. Furthermore, it was confirmed that large velocity gradients were generated in the nasal vestibule and larynx regions, as well as increased turbulent air kinetic energy and wall sheer stress.
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http://dx.doi.org/10.1016/j.resp.2019.103304DOI Listing
January 2020

Second-generation antipsychotics activate platelets in antipsychotic-naive and antipsychotic-free patients with schizophrenia: A retrospective study.

Int J Psychiatry Med 2020 03 5;55(2):105-113. Epub 2019 Sep 5.

Department of Psychiatry, College of Medicine, Konyang University, Daejeon, Republic of Korea.

Objective: Among the risk factors for cerebrovascular/cardiovascular disease or thromboembolic events caused by the administration of second-generation antipsychotics, clinicians have mainly focused on metabolic side effects, with little interest in the effects on platelet activity. Because excessive platelet activity can increase the risk for cerebrovascular/cardiovascular disease, the aim of this study was to investigate the effect of second-generation antipsychotics on platelet activity in patients with schizophrenia.

Methods: The medical records of patients with schizophrenia who were treated with second-generation antipsychotics were retrospectively reviewed. The degree of platelet activation was assessed by measuring the mean platelet component.

Results: Wilcoxon signed-rank test revealed that mean platelet component levels were significantly decreased by the administration of second-generation antipsychotics (V = 20; p < 0.05), suggesting that the administration of second-generation antipsychotics may increase platelet activation.

Conclusion: Because platelet activation is an additional risk factor for the occurrence of cerebrovascular/cardiovascular disease, results of this study suggest that clinicians should carefully monitor the degree of platelet activation after the administration of second-generation antipsychotics.
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http://dx.doi.org/10.1177/0091217419874277DOI Listing
March 2020

Advanced measurement and diagnosis of the effect on the underlayer roughness for industrial standard metrology.

Sci Rep 2019 Jan 31;9(1):1018. Epub 2019 Jan 31.

Division of Industrial Metrology, Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea.

In current nanoscale semiconductor fabrications, high dielectric materials and ultrathin multilayers have been selected to improve the performance of the devices. Thus, interface effects between films and the quantification of surface information are becoming key issues for determining the performance of the semiconductor devices. In this paper, we developed an easy, accurate, and nondestructive diagnosis to investigate the interface effect of hafnium oxide ultrathin films. A roughness scaling method that artificially modified silicon surfaces with a maximum peak-to-valley roughness range of a few nanometers was introduced to examine the effect on the underlayer roughness. The critical overlayer roughness was be defined by the transition of RMS roughness which was 0.18 nm for the 3 nm thick hafnium oxide film. Subsequently, for the inline diagnostic application of semiconductor fabrication, the roughness of a mass produced hafnium film was investigated. Finally, we confirmed that the result was below the threshold set by our critical roughness. The RMS roughness of the mass produced hafnium oxide film was 0.11 nm at a 500 nm field of view. Therefore, we expect that the quantified and standardized critical roughness managements will contribute to improvement of the production yield.
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http://dx.doi.org/10.1038/s41598-018-36991-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6355768PMC
January 2019

Biological activities and chemical components of Wight & Arn.

Nat Prod Res 2020 Nov 19;34(22):3262-3266. Epub 2019 Jan 19.

Department of Fine Chemistry, Cosmetic R&D Center Cosmetic Industry Coupled Collaboration Center Seoul National University of Science and Technology, Seoul, South Korea.

In this study, we investigated the antimicrobial, antioxidant, and cytoprotective activities of ethanol extract and the ethyl acetate (EtOAc) fraction of Wight & Arn. The EtOAc fraction exhibited antimicrobial effects against most of the microorganisms that were tested, including , , and, , but not . In addition to its excellent antioxidant activity, the EtOAc fraction attenuated the UVB-induced cell death via upregulation of caspase-3 expression in human keratinocytes. The HPLC/ESI-MS/MS analysis allowed identification of the components in the EtOAc fraction. Overall, our results suggest that is a valuable source of bioactive compounds for the development of pharmaceuticals and cosmetics.
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http://dx.doi.org/10.1080/14786419.2018.1557171DOI Listing
November 2020

Changes of auditory stimulus processing in sevoflurane-induced sedation.

Neurosci Lett 2019 04 9;698:121-125. Epub 2019 Jan 9.

Department of Pediatric Dentistry and Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea. Electronic address:

Despite the widespread use in clinical practice, little research has been done on mechanisms of sedation. In particular, little is known about the changes in the information processing of external stimuli in sedation. The aim of this study was to investigate the changes of event-related potential (ERP) in auditory passive oddball paradigm when the sedation was induced by sevoflurane inhalation. Electroencephalography (EEG) measurements were obtained for each subject using 32-channel EEG recording devices. Sevoflurane was administered at an initial concentration of 0.8 vol% to induce sedative state. Auditory stimulation based on the passive oddball paradigm was delivered to the subject via an earphone before and after sevoflurane administration. After ERP was extracted from the measured EEG, the topographic distribution of ERP, the temporal changes of ERP in each channel, and the statistical difference in ERP between awake and sedation were analyzed. In the awake state, P300 was observed at 320-360 ms latency, and P300 was concentrated in the frontal and central area. P300 amplitude was significantly decreased in sedation compared to awake. Sevoflurane-induced sedation caused a decrease in P300 amplitude. This result may reflect the weakening of the cognitive function governing attentional process and stimuli discrimination during sedation.
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http://dx.doi.org/10.1016/j.neulet.2019.01.018DOI Listing
April 2019

Negative Cellular Effects of Urban Particulate Matter on Human Keratinocytes Are Mediated by P38 MAPK and NF-κB-dependent Expression of TRPV 1.

Int J Mol Sci 2018 Sep 7;19(9). Epub 2018 Sep 7.

Molecular Dermatology Laboratory, Department of Integrative Biotechnology, College of Biotechnology and Bioengineering, Sungkyunkwan University, Suwon City, Gyunggi Do 16419, Korea.

Urban particulate matter (UPM) exerts negative effects on various human organs. Transient receptor potential vanilloid 1 (TRPV1) is a polymodal sensory transducer that can be activated by multiple noxious stimuli. This study aimed to explore the effects of the UPM 1648a on the expression of TRPV1, and its regulatory mechanisms in HaCaT cells. UPM enhanced TRPV 1 promoter-luciferase reporter activity. UPM also increased expression of the TRPV 1 gene as evidenced by increased mRNA and protein levels of TRPV 1. In addition, elucidation of the underlying mechanism behind the UPM-mediated effects on TRPV 1 expression revealed that UPM can upregulate expression of the TRPV1 gene by activating activator protein-1 (AP-1) and nuclear factor kappa B (NF-κB). The UPM treatment also altered Ca influx and cell proliferation, as well as production of interleukin-8 (IL-8), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β). In addition, these UPM-induced effects were attenuated by SB203580 and ammonium pyrrolidinedithiocarbamate (PDTC). However, SP600125 and PD98059 did not alter the UPM-induced effects. Taken together, these findings indicate that UPM upregulates expression of the TRPV 1 gene, which is mediated by the p38 mitogen-activated protein kinase (MAPK) and NF-κB signaling pathways and suggest that UPM is a potential irritant that can induce skin processes such as aging and inflammatory responses.
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http://dx.doi.org/10.3390/ijms19092660DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6163502PMC
September 2018

A modified new method beyond endoscopic muscularis dissection for an exophytic gastric tumor.

VideoGIE 2018 Jun 4;3(6):177-178. Epub 2018 Apr 4.

Division of Gastroenterology, Presbyterian Medical Center, Jeonju, South Korea.

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http://dx.doi.org/10.1016/j.vgie.2018.03.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6098666PMC
June 2018

Flow visualization through particle image velocimetry in realistic model of rhesus monkey's upper airway.

Respir Physiol Neurobiol 2018 05 10;251:16-27. Epub 2018 Feb 10.

Faculty of Engineering Sciences, Kyushu University, Japan.

Studies concerning inhalation toxicology and respiratory drug-delivery systems require biological testing involving experiments performed on animals. Particle image velocimetry (PIV) is an effective in vitro technique that reveals detailed inhalation flow patterns, thereby assisting analyses of inhalation exposure to various substances. A realistic model of a rhesus-monkey upper airway was developed to investigate flow patterns in its oral and nasal cavities through PIV experiments performed under steady-state constant inhalation conditions at various flow rates-4, 10, and 20 L/min. Flow rate of the fluid passing through the inlet into the trachea was measured to obtain characteristic flow mechanisms, and flow phenomena in the model were confirmed via characterized flow fields. It was observed that increase in flow rate leads to constant velocity profiles in upper and lower trachea regions. It is expected that the results of this study would contribute to future validation of studies aimed at developing in silico models, especially those involving computational fluid dynamic (CFD) analysis.
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http://dx.doi.org/10.1016/j.resp.2018.02.007DOI Listing
May 2018

Altered Functional Connectivity of the Default Mode Network in Low-Empathy Subjects.

Yonsei Med J 2017 Sep;58(5):1061-1065

Department of Psychiatry, Konyang University College of Medicine, Daejeon, Korea.

Empathy is the ability to identify with or make a vicariously experience of another person's feelings or thoughts based on memory and/or self-referential mental simulation. The default mode network in particular is related to self-referential empathy. In order to elucidate the possible neural mechanisms underlying empathy, we investigated the functional connectivity of the default mode network in subjects from a general population. Resting state functional magnetic resonance imaging data were acquired from 19 low-empathy subjects and 18 medium-empathy subjects. An independent component analysis was used to identify the default mode network, and differences in functional connectivity strength were compared between the two groups. The low-empathy group showed lower functional connectivity of the medial prefrontal cortex and anterior cingulate cortex (Brodmann areas 9 and 32) within the default mode network, compared to the medium-empathy group. The results of the present study suggest that empathy is related to functional connectivity of the medial prefrontal cortex/anterior cingulate cortex within the default mode network. Functional decreases in connectivity among low-empathy subjects may reflect an impairment of self-referential mental simulation.
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http://dx.doi.org/10.3349/ymj.2017.58.5.1061DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5552636PMC
September 2017

Neuroendocrine Tumors in the Stomach, Duodenum, and Pancreas Accompanied by Novel MEN1 Gene Mutation.

Korean J Gastroenterol 2017 Mar;69(3):181-186

Division of Gastroenterology, Department of Internal Medicine, Presbyterian Medical Center, Jeonju, Korea.

Multiple endocrine neoplasia type 1 (MEN1) syndrome is a relatively rare disease, characterized by the occurrence of multiple endocrine tumors in the parathyroid and pituitary glands as well as the pancreas. Here, we report a case of MEN1 with neuroendocrine tumors (NETs) in the stomach, duodenum, and pancreas. A 53-year-old man visited our hospital to manage gastric NET. Five years prior to his visit, he had undergone surgery for incidental meningioma. His brother had pancreatic nodules and a history of surgery for adrenal adenoma. His brother's daughter also had pancreatic nodules, but had not undergone surgery. The lesion was treated by endoscopic submucosal dissection and diagnosed as a grade 1 NET. Another small NET was detected in the second duodenal portion, resected by endoscopic submucosal dissection, which was also diagnosed as a grade 1 NET. During evaluation, three nodules were detected in the pancreas, and no evidence of pituitary, parathyroid tumors, or metastasis was observed. After surgery, the pancreatic lesions were diagnosed as NETs, with the same immunohistochemical patterns as those of the stomach and duodenum. Genetic testing was performed, and a heterozygous mutation was detected in the MEN1 gene, which is located on 11q13.
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http://dx.doi.org/10.4166/kjg.2017.69.3.181DOI Listing
March 2017

Open reduction and internal fixation for intraarticular fracture of metacarpal head.

Orthopade 2017 Jul;46(7):617-624

Department of Orthopaedic Surgery, CHA Bundang Medical Center, CHA University School of Medicine, 59 Yatap-ro, Bundang-gu, 463-712, Seongnam-si, Gyeonggi-do, Korea (Republic of).

Intraarticular fracture of the metacarpophalangeal (MP) joint presents complex problems related to the sophisticated functional aspects of the hand. Injury to the metacarpal head may have a severe effect on hand function but few studies have investigated the management of this condition. In this study, we applied open reduction and internal fixation for the displaced fracture of the metacarpal head and report the clinical and radiographic outcomes of our experience. Thirteen patients (12 men, 1 woman; mean age 21 years) were included in this study, and medical records and radiographs were reviewed retrospectively. The average follow-up period was 12.5 months. Range of motion (ROM) and Disabilities of the Arm, Shoulder, and Hand (DASH) scores were analyzed, and functional results and serial radiographs were investigated for the maintenance of articular congruity and fracture union. The injured fingers were 5 long, 4 small, 2 ring, and 2 index. Five cases were fixed with K‑wires, 5 cases with headless screws, and 3 cases with screw and K‑wire. The average range of injured MP joint motion was 89°, total active range of motion (TAM) was 265°, and the average DASH score was 3.8 at the last follow-up. All patients showed fracture union on the radiographs and no patient showed significant articular surface incongruence or degenerative change. Open reduction and internal fixation of the metacarpal head fracture had favorable outcomes in our study. The authors suggest accurate reduction and stable fixation for better functional results in metacarpal head fractures.
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http://dx.doi.org/10.1007/s00132-017-3392-8DOI Listing
July 2017

Risk factors and management for pyloric stenosis occurred after endoscopic submucosal dissection adjacent to pylorus.

Medicine (Baltimore) 2016 Dec;95(50):e5633

Division of Gastroenterology, Department of Internal Medicine, Presbyterian Medical Center, Jeonju, Korea.

Endoscopic submucosal dissection (ESD) has been widely accepted as a curative treatment for gastric neoplasm. Pyloric stenosis is a chronic complication that can be caused by ESD. The aim of this study is to clarify the risk factors and management for pyloric stenosis. From January 2004 to January 2014, a total of 126 patients who underwent ESD adjacent to pylorus were reviewed retrospectively. Pyloric mucosal defect was defined as when any resection margin of ESD was involved in the pyloric ring. Pyloric stenosis was defined as when a conventional endoscope could not be passed to the duodenum. Among the 126 patients, pyloric stenosis was identified in 9. In a univariate analysis, pyloric stenosis was more common in older patients (P < 0.05) and in lesions with resections over 75% of the pyloric ring circumference (P < 0.001). In a multivariate analysis, the factor that was associated with pyloric stenosis was the extent of the pyloric ring dissection (P < 0.001). Four of the 9 patients with pyloric stenosis had mild dyspepsia, and the others had gastric outlet obstruction symptoms. The 5 symptomatic patients underwent endoscopic balloon dilation (EBD), and the frequency of EBD was 1 to 8 times. The asymptomatic patients were treated conservatively. The incidence of pyloric stenosis was higher in lesions with resections over 75% of the pyloric ring circumference. Although EBD was an effective treatment for pyloric stenosis, conservative management was also helpful in patients who had mild symptoms.
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http://dx.doi.org/10.1097/MD.0000000000005633DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5268054PMC
December 2016

Effects of Ganodermanondiol, a New Melanogenesis Inhibitor from the Medicinal Mushroom Ganoderma lucidum.

Int J Mol Sci 2016 Oct 27;17(11). Epub 2016 Oct 27.

Department of Biomedical Chemistry, Konkuk University, Chungju 27478, Korea.

, a species of the Basidiomycetes class, has been attracting international attention owing to its wide variety of biological activities and great potential as an ingredient in skin care cosmetics including "skin-whitening" products. However, there is little information available on its inhibitory effect against tyrosinase activity. Therefore, the objectives of this study were to investigate the chemical composition of and its inhibitory effects on melanogenesis. We isolated the active compound from using ethanol extraction and ethyl acetate fractionation. In addition, we assayed its inhibitory effects on tyrosinase activity and melanin biosynthesis in B16F10 melanoma cells. In this study, we identified a bioactive compound, ganodermanondiol, which inhibits the activity and expression of cellular tyrosinase and the expression of tyrosinase-related protein-1 (TRP-1), TRP-2, and microphthalmia-associated transcription factor (MITF), thereby decreasing melanin production. Furthermore, ganodermanondiol also affected the mitogen-activated protein kinase (MAPK) cascade and cyclic adenosine monophosphate (cAMP)-dependent signaling pathway, which are involved in the melanogenesis of B16F10 melanoma cells. The finding that ganodermanondiol from exerts an inhibitory effect on tyrosinase will contribute to the use of this mushroom in the preparation of skin care products in the future.
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http://dx.doi.org/10.3390/ijms17111798DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5133799PMC
October 2016

An Intractable Caustic Esophageal Stricture Successfully Managed with Sequential Treatment Comprising Incision with an Insulated-Tip Knife, Balloon Dilation, and an Oral Steroid.

Clin Endosc 2016 Nov 12;49(6):560-563. Epub 2016 Aug 12.

Division of Gastroenterology, Department of Internal Medicine, Presbyterian Medical Center, Jeonju, Korea.

Bougie or balloon dilation is a good short-term treatment for caustic esophageal strictures, although recurrence after dilation occurs in approximately 30% of these cases. Therefore, long-term treatment options are required in some cases, and endoscopic incisional therapy has been used for patients with an anastomotic stricture in the gastrointestinal tract. A 58-year-old woman presented with severe swallowing difficulty because of a caustic esophageal stricture, which was caused by accidental exposure to anhydrous acetic acid at infancy. She had undergone several previous bougie and balloon dilations but the stricture did not improve. We performed sequential treatment comprising incision with an insulated-tip knife, balloon dilation, and an oral steroid, which resulted in the patient's symptoms markedly improving. Thus, we report this case of an intractable caustic esophageal stricture, which was successfully treated using combined endoscopic sequential treatment.
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http://dx.doi.org/10.5946/ce.2016.048DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5152773PMC
November 2016

The result of surgical treatment of medial epicondylitis: analysis with more than a 5-year follow-up.

J Shoulder Elbow Surg 2016 Oct 1;25(10):1704-9. Epub 2016 Aug 1.

Department of Orthopaedic Surgery, CHA Bundang Medical Center, School of Medicine, CHA University, Gyeonggi, Republic of Korea.

Background: Angiofibroblastic changes of a musculotendinous origin at the medial epicondyle characterize medial epicondylitis of the elbow. Although nonsurgical treatment is the primary approach for medial epicondylitis, surgical treatment should be considered when conservative therapy fails. This study reports the results of surgical treatment of medial epicondylitis monitored for more than 5 years.

Methods: This study included 55 patients with 63 cases of medial epicondylitis between 2000 and 2010. The conservative treatment periods lasted for a minimum of 1 year, and steroid injections were administered more than twice before surgery. One surgeon conducted the surgical procedures. The Nirschl and Pettrone grades, visual analog scale (VAS) scores, Disabilities of the Arm, Shoulder and Hand (DASH) scores, Mayo Elbow Performance scores, and grip strengths were analyzed. Statistical analyses were performed using paired t tests.

Results: The mean VAS score improved from 8.5 to 2.4 (P <.001). Nirschl and Pettrone grades rated 43% (27 elbows) as excellent and 51% (32 elbows) as good. The Mayo Elbow Performance scores improved from 72 to 88 (P <.001) and DASH scores from 57 to 23 (P <.001). The mean grip strength of the affected side improved from 30 to 43 lb (P <.001). The mean time required to return to work and exercise was 2.8 months and 4.8 months, respectively. One case of heterotrophic ossification, which had no functional instability afterward, was seen.

Conclusion: The results indicate that surgical treatment of medial epicondylitis could be an effective and safe treatment when conservative treatment fails.
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http://dx.doi.org/10.1016/j.jse.2016.05.010DOI Listing
October 2016

Estimating functional connectivity using 2D tangential components in MEG sensor space.

J Neurosci Methods 2016 Jan 21;257:64-75. Epub 2015 Sep 21.

Center for Biosignals, Division of Convergence Technology, Korea Research Institute of Standards and Science, Daejeon 305-340, Republic of Korea; Department of Medical Physics, University of Science and Technology, Daejeon 305-350, Republic of Korea.

Background: Connectivity analysis in magnetoencephalography (MEG) sensor space is commonly used for the preliminary estimation of the functional relationship between cortical areas, but the results are difficult to interpret due to the field spread effect. To improve the interpretability of sensor-level connectivity analysis, we introduce and test a new connectivity measure based on imaginary coherence in this study.

New Method: MEG signals from axial gradiometers are subjected to a wavelet transform at a frequency of interest, and are used to reconstruct 2D tangential magnetometer signals. The Euclidean norm of imaginary coherence values obtained from four available pairs between 2D tangential components at two locations is then used to estimate functional connectivity between sensor locations. The use of this new connectivity measure can be extended to 2D planar gradiometer signals or 3D source signals, where the functional relationship between multi-dimensional signals at different locations needs to be quantified as scalar variables.

Results: The proposed method was applied to measured and simulated auditory evoked MEG data. The Euclidean norm of imaginary coherence reliably eliminated the field spread effect and showed increased inter-hemispheric coherence between sensors above the left and the right auditory cortex. The significance of the results was tested by introducing variability in spontaneous brain activities in multi-trial evoked data simulations.

Comparison With Existing Method: The distribution of imaginary coherence among axial gradiometer signals shows peaks not at the sensors directly above the neuronal current sources, but at sensors with field extreme.
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http://dx.doi.org/10.1016/j.jneumeth.2015.09.012DOI Listing
January 2016

Efficiency of Non-Contrast-Enhanced Liver Imaging Sequences Added to Initial Rectal MRI in Rectal Cancer Patients.

PLoS One 2015 8;10(9):e0137320. Epub 2015 Sep 8.

Department of Chiropractic, Graduate School of Health promotion, Hanseo University, Seosan-Si, Korea.

Purpose: The purpose of this study was to estimate the value of addition of liver imaging to initial rectal magnetic resonance imaging (MRI) for detection of liver metastasis and evaluate imaging predictors of a high risk of liver metastasis on rectal MRI.

Methods: We enrolled 144 patients who from October 2010 to May 2013 underwent rectal MRI with T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI) (b values = 50, 500, and 900 s/mm2) of the liver and abdominopelvic computed tomography (APCT) for the initial staging of rectal cancer. Two reviewers scored the possibility of liver metastasis on different sets of liver images (T2WI, DWI, and combined T2WI and DWI) and APCT and reached a conclusion by consensus for different analytic results. Imaging features from rectal MRI were also analyzed. The diagnostic performances of CT and an additional liver scan to detect liver metastasis were compared. Multivariate logistic regression to determine independent predictors of liver metastasis among rectal MRI features and tumor markers was performed. This retrospective study was approved by the Institutional Review Board, and the requirement for informed consent was waived.

Results: All sets of liver images were more effective than APCT for detecting liver metastasis, and DWI was the most effective. Perivascular stranding and anal sphincter invasion were statistically significant for liver metastasis (p = 0.0077 and p = 0.0471), while extramural vascular invasion based on MRI (mrEMVI) was marginally significant (p = 0.0534).

Conclusion: The addition of non-contrast-enhanced liver imaging, particularly DWI, to initial rectal MRI in rectal cancer patients could facilitate detection of liver metastasis without APCT. Perivascular stranding, anal sphincter invasion, and mrEMVI detected on rectal MRI were important imaging predictors of liver metastasis.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0137320PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4562629PMC
May 2016

Bedside Endoscopic Ultrasound-guided Transgastric Gallbladder Aspiration and Lavage in a High-risk Surgical Case Due to Acute Cholecystitis Accompanied by Multiorgan Failure.

Korean J Gastroenterol 2015 Jun;65(6):370-4

Department of Gastroenterology, Presbyterian Medical Center, Seonam University College of Medicine, Jeonju, Korea.

Cholangitis and cholecystitis are intra-abdominal infections that show poor prognosis upon progression to sepsis and multiorgan failure. Administration of antibiotics with high antimicrobial susceptibility and removal of infected bile at the initial treatment are important. After undergoing ERCP for diagnostic purposes, a 58-year-old man developed acute cholangitis and cholecystitis accompanied by rhabdomyolysis, multi-organ failure, and severe sepsis. Broad-spectrum antibiotics with bedside endoscopic nasobiliary drainage were administered, but clinical symptoms did not improve. Therefore, bedside EUS-guided transgastric gallbladder aspiration and lavage was performed, resulting in successful treatment of the patient. We report the above described case along with a discussion of relevant literature.
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http://dx.doi.org/10.4166/kjg.2015.65.6.370DOI Listing
June 2015

Proximal Segment Changes After Bilateral Sagittal Split Ramus Osteotomy in Facial Asymmetry Patients.

J Oral Maxillofac Surg 2015 Aug 26;73(8):1592-605. Epub 2015 Feb 26.

Assistant Professor, Department of Orthodontics, Dental Research Institute, Pusan National University Dental Hospital, Yangsan, South Korea.

Purpose: To investigate the 3-dimensional postoperative changes in the proximal segments in patients with facial asymmetry according to the anteroposterior skeletal patterns.

Materials And Methods: A total of 51 patients with facial asymmetry who had undergone Le Fort I osteotomy and sagittal split ramus osteotomy (SSRO) with rigid fixation were classified according to their anteroposterior skeletal patterns. Cone-beam computed tomography (CBCT) data were obtained before (T0) and 6 months (T1) after surgery. The position, angulation, and distance of the proximal segment were measured from the CBCT superimposition.

Results: Comparing the T0 and T1 CBCT data, almost no significant differences were found in the condylar head position in any of the groups (P > .05), except for the axial condylar head position on the deviated side in the skeletal Class I group (P < .05) and the sagittal condylar head position on the deviated side in the skeletal Class III group (P < .05). However, the changes in the coronoid process and ramus down varied (P < .05), and these movements were related to changes in the ramal plane. Comparing the deviated and nondeviated sides, significant differences were found only in the skeletal Class I group (P < .05).

Conclusions: The most influential factors affecting differences between the deviated and nondeviated sides in patients with facial asymmetry after bilateral SSRO could be the direction of the surgical movement of the distal segment of the mandible rather than its extent.
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http://dx.doi.org/10.1016/j.joms.2015.02.021DOI Listing
August 2015

Intramural gastric abscess caused by a toothpick presenting as a subepithelial tumor.

Clin Endosc 2014 May 31;47(3):254-7. Epub 2014 May 31.

Division of Gastrointestinology, Department of Internal Medicine, Presbyterian Medical Center, Jeonju, Korea.

In the present report, we describe an unusual case of an intramural gastric abscess caused by a foreign body, detected in the form of a subepithelial tumor. A 64-year-old woman was referred to our gastroenterology clinic for further evaluation of a gastric subepithelial tumor. The patient presented with a 1-month history of sustained dull epigastric pain. Esophagogastroduodenoscopy revealed an ill-demarcated, round, smooth, protruding lesion with a small central erosion on the great curvature of the proximal antrum. Endoscopic ultrasonography indicated the presence of an ovoid, heterogeneous, hypoechoic lesion with small echogenic foci located in the submucosa and muscularis propria layers. An abdominal computed tomography scan showed focal gastric wall thickening and regional lymph node enlargement. Endoscopic submucosal dissection was performed for definite diagnosis and management. Thus, we detected a toothpick and removed it using grasping forceps. The final diagnosis was an intramural gastric abscess caused by a toothpick.
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http://dx.doi.org/10.5946/ce.2014.47.3.254DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4058544PMC
May 2014

The effect of word imagery on priming effect under a preconscious condition: an fMRI study.

Hum Brain Mapp 2014 Sep 1;35(9):4795-804. Epub 2014 Apr 1.

Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Korea.

Semantic priming is affected by the degree of association and how readily a word is imagined. In the association effect, activity in the perisylvian structures including the bilateral inferior frontal gyrus, the left middle temporal gyrus, and the supramarginal gyrus was correlated. However, little is known about the brain regions related to the effect of imagery word under the preconscious condition. Forty word pairs for high (HA)-, low (LA)-, and nonassociation (NA), nonword (NW) conditions were presented. Each 40 association word pairs (HA and LA) included 20 high (HI) and 20 low (LI) imagery prime stimuli, using a visually presented lexical decision task. A trial consisted of 30 ms prime, 30 ms mask, 500 ms probe, and 2-8 s stimulus onset asynchrony. Brain activation was measured using functional magnetic resonance imaging during word discrimination. Behavioral data indicated that the shortest response time (RT) was given for HA words, followed by LA and NA, and NW showed the longest RT (P < 0.01). RT was faster in HI than LI within HA, but not LA conditions (P < 0.01). Functional neuroimaging showed that differential brain regions for high imagery (HI) and low imagery (LI) words within low prime-target word association were observed in the left precuneus, left posterior cingulate gyrus, and right cuneal cortex. The present findings demonstrate that the effect of the degree of imagery on semantic priming occurs during the early stage of language processing, indicating an "automatic imagery priming effect." Our paradigm may be useful to explore semantic deficit related to imagery in various psychiatric disorders.
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http://dx.doi.org/10.1002/hbm.22512DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4312897PMC
September 2014