Sung Tae Kim

Inje University Paik Hospital, Sŏul, Seoul, South Korea

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Publications (280)958.77 Total impact

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    ABSTRACT: The N-end rule pathway is a proteolytic system, in which single N-terminal residues act as a determinant of a class of degrons, called N-degrons. In the ubiquitin (Ub)-proteasome system, specific recognition components, called N-recognins, recognize N-degrons and accelerate polyubiquitination and proteasomal degradation of the substrates. In this study, we show that the pathway regulates the activity of the macroautophagic receptor SQSTM1/p62 (sequestosome 1) through N-terminal arginylation (Nt-arginylation) of endoplasmic reticulum (ER)-residing molecular chaperones, including HSPA5/GRP78/BiP, CALR (calreticulin), and protein disulfide isomerases. The arginylation is co-induced with macroautophagy (hereafter autophagy) as part of innate immunity to cytosolic DNA and when misfolded proteins accumulate under proteasomal inhibition. Following cytosolic relocalization and arginylation, Nt-arginylated HSPA5 (R-HSPA5) is targeted to autophagosomes and degraded by lysosomal hydrolases through the interaction of its N-terminal Arg (Nt-Arg) with ZZ domain of SQSTM1. Upon binding to Nt-Arg, SQSTM1 undergoes a conformational change, which promotes SQSTM1self-polymerization and interaction with LC3, leading to SQSTM1 targeting to autophagosomes. Cargoes of R-HSPA5 include cytosolic misfolded proteins destined to be degraded through autophagy. Here, we discuss the mechanisms by which the N-end rule pathway regulates SQSTM1-dependent selective autophagy.
    No preview · Article · Jan 2016 · Autophagy
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    ABSTRACT: Progressed tissue culture techniques have allowed to easily obtain mass product of Tissue-Cultured Mountain Ginseng over 100 years old (TCMG-100). We investigated the effects of TCMG-100 extract on erectile function by in vitro and in vivo studies.
    Preview · Article · Nov 2015 · Journal of ginseng research
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    ABSTRACT: We assessed structural brain damage in obstructive sleep apnea syndrome (OSA) patients (21 males) and the effects of long-term continuous positive airway pressure (CPAP) treatment (18.2 ± 12.4 months; 8-44 months) on brain structures and investigated the relationship between severity of OSA and effects of treatment. Using deformation-based morphometry to measure local volume changes, we identified widespread neocortical and cerebellar atrophy in untreated patients compared to controls (59 males; Cohen's D = 0.6; FDR < 0.05). Analysis of longitudinally scanned magnetic resonance imaging (MRI) scans both before and after treatment showed increased brain volume following treatment (FDR < 0.05). Volume increase was correlated with longer treatment in the cortical areas that largely overlapped with the initial atrophy. The areas overlying the hippocampal dentate gyrus and the cerebellar dentate nucleus displayed a volume increase after treatment. Patients with very severe OSA (AHI > 64) presented with prefrontal atrophy and displayed an additional volume increase in this area following treatment. Higher impairment of working memory in patients prior to treatment correlated with prefrontal volume increase after treatment. The large overlap between the initial brain damage and the extent of recovery after treatment suggests partial recovery of nonpermanent structural damage. Volume increases in the dentate gyrus and the dentate nucleus possibly likely indicate compensatory neurogenesis in response to diminishing oxidative stress. Such changes in other brain structures may explain gliosis, dendritic volume increase, or inflammation. This study provides neuroimaging evidence that revealed the positive effects of long-term CPAP treatment in patients with OSA. Hum Brain Mapp, 2015. © 2015 Wiley Periodicals, Inc.
    No preview · Article · Oct 2015 · Human Brain Mapping
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    ABSTRACT: Objective: To determine the independent and synergistic effects of amyloid and small vessel disease (SVD) burden on longitudinal cognitive decline in patients with subcortical vascular dementia (SVaD). Methods: A longitudinal cohort study was conducted involving patients from outpatient clinics of 2 tertiary referral centers. Sixty-one patients with SVaD were prospectively recruited and underwent MRI, 11C-Pittsburgh compound B (PiB) PET at baseline, and a 3-year annual neuropsychological follow-up. Effects of PiB positivity and SVD markers (white matter hyperintensities [WMH], lacunes, and microbleeds) on longitudinal cognitive decline were evaluated using generalized estimation equation after controlling for age, sex, education, APOE4 allele, and follow-up interval. Results: When individual neuropsychological tests were used as outcome measures, PiB positivity was associated with faster cognitive decline in attention, visuospatial, visual memory, and global cognition function. Higher WMH burden was associated with faster cognitive decline in attention, visuospatial, visual recognition memory, and semantic/phonemic fluency function, whereas lacunes and microbleeds had no significant effects. When global dementia rating (Clinical Dementia Rating sum of boxes) was considered as an outcome measure, however, only PiB positivity was associated with faster cognitive decline. Significant interactions between PiB positivity and higher SVD burden were found to affect cognitive decline in semantic word fluency (from WMH burden) and global dementia rating (from microbleed burden). Conclusions: In SVaD patients, amyloid burden, independently or interactively with SVD, contributed to longitudinal cognitive decline. Amyloid deposition was the strongest poor prognostic factor.
    No preview · Article · Oct 2015 · Neurology
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    ABSTRACT: The purpose of this study was to analyze outcomes in patients treated with gamma knife radiosurgery (GKS) for brain metastases from non-small cell lung cancer (NSCLC). We retrospectively reviewed the medical records of 817 patients who underwent GKS for brain metastases from NSCLC between January 2002 and December 2012. A total of 1363 GKS procedures were performed for 2970 lesions. The median overall survival time from the initial GKS was 13 months and the salvage treatment-free survival from the first GKS was 6.5 months. Younger age (≤65 years), female sex, better RPA class, higher DS-GPA score, adenocarcinoma, synchronous onset, and lower integrated value of the "numbers and cumulative volume of tumors" were associated with better outcomes. Among the 601 patients with an available follow up image, the pattern of the first progression after initial GKS was the development of new lesions in 356 patients (59.2 %), regrowth of treated lesions in 106 patients (17.6 %), and leptomeningeal seeding (LMS) in 51 patients (8.5 %). Among the deceased, the last MRI performed prior to death was evaluated in 409 patients and showed progression in 263 patients (64.3 %), despite multiple salvage treatments. LMS was identified in 63 patients (15.4 %); a rate much higher than the incidence at first progression. Intracranial tumor burden, defined as the integrated value of the "number of the lesions and cumulative tumor volume", is a new prognostic factor of greater significance than tumor volume or number alone when analyzed as separate factors. Although the cause of death was not progression of brain lesions in the majority of patients, the brain lesions tended to have been persistently progressive in most patients, despite repeated salvage treatment. LMS is an important pattern of treatment failure, in addition to local progression or development of new lesions, particularly in the terminal phase of the disease.
    No preview · Article · Sep 2015 · Journal of Neuro-Oncology
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    ABSTRACT: Friction in a post-tensioning system has a significant effect on the distribution of the prestressing force of tendons in prestressed concrete structures. However, attempts to derive friction coefficients using conventional electrical resistance strain gauges do not usually lead to reliable results, mainly due to the damage of sensors and lead wires during the insertion of strands into the sheath and during tensioning. In order to overcome these drawbacks of the existing measurement system, the Smart Strand was developed in this study to accurately measure the strain and prestressing force along the strand. In the Smart Strand, the core wire of a 7-wire strand is replaced with carbon fiber reinforced polymer in which the fiber Bragg grating sensors are embedded. As one of the applications of the Smart Strand, friction coefficients were evaluated using a full-scale test of a 20 m long beam. The test variables were the curvature, diameter, and filling ratio of the sheath. The analysis results showed the average wobble and curvature friction coefficients of 0.0038/m and 0.21/radian, respectively, which correspond to the middle of the range specified in ACI 318-08 in the U.S. and Structural Concrete Design Code in Korea. Also, the accuracy of the coefficients was improved by reducing the effective range specified in these codes by 27–34 %. This study shows the wide range of applicability of the developed Smart Strand system.
    No preview · Article · Sep 2015
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    ABSTRACT: The equipment and techniques associated with magnetic resonance imaging (MRI) have rapidly evolved. The development of 3.0 Tesla MRI has enabled high-resolution imaging of the intracranial vessel wall. High-resolution MRI (HRMRI) can yield excellent visualization of both the arterial wall and lumen, thus facilitating the detection of the primary and secondary features of intracranial arterial dissection. In the present report, we describe the manner in which HRMRI affected our endovascular treatment planning strategy in 2 cases with unruptured intracranial vertebral artery dissection aneurysm. HRMRI provides further information about the vessel wall and the lumen of the unruptured intracranial vertebral artery dissecting aneurysm, which was treated by an endovascular approach in the 2 current cases.
    Full-text · Article · Sep 2015 · Journal of Korean Neurosurgical Society
  • Mi-kyung Han · Sohwa Kim · Sung Tae Kim · Jong Chan Lee
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    ABSTRACT: An efficient bismuth tribromide catalyzed oxidation of various alcohols with aqueous hydrogen peroxide is described, leading to the corresponding carbonyl compounds.
    No preview · Article · Sep 2015 · Synlett
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    ABSTRACT: We aimed to investigate the relationship between education and cortical thickness in cognitively normal individuals to determine whether education attenuated the association of advanced aging and cortical thinning. A total of 1,959 participants, in whom education levels were available, were included in the final analysis. Cortical thickness was measured on high-resolution MRIs using a surface-based method. Multiple linear regression analysis was performed for education level and cortical thickness, after controlling for possible confounders. High levels of education were correlated with increased mean cortical thickness throughout the entire cortex (p = 0.003). This association persisted after controlling for vascular risk factors. Statistical maps of cortical thickness showed that the high levels of education were correlated with increased cortical thickness in the bilateral premotor areas, anterior cingulate cortices, perisylvian areas, right superior parietal lobule, left lingual gyrus, and occipital pole. There were also interactive effects of age and education on the mean cortical thickness (p = 0.019). Our findings suggest the protective effect of education on cortical thinning in cognitively normal older individuals, regardless of vascular risk factors. This effect was found only in the older participants, suggesting that the protective effects of education on cortical thickness might be achieved by increased resistance to structural loss from aging rather than by simply providing a fixed advantage in the brain. © 2015 American Academy of Neurology.
    Full-text · Article · Jul 2015 · Neurology

  • No preview · Article · Jul 2015
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    ABSTRACT: Obesity is a common cause of hyperlipidemia, which is a major coronary risk factor. Previous studies have shown red yeast rice (RYR) effectiveness in lowering low-density lipoprotein cholesterol. The aim of this study was to investigate the effects of RYR on obesity and hyperlipidemia. Mice were randomly separated into five groups: the control group with a normal diet, the high-fat diet (HFD) group fed a HFD without any treatment, and HFD-fed groups supplemented with RYR (1 g/kg/day for 8 weeks, 1 g/kg/day for 12 weeks, and 2.5 g/kg/day for 8 weeks). Body weight was recorded twice and food intake thrice weekly. Liver and fat pads were surgically removed and weighed. The levels of lipid parameters, liver enzymes, and leptin levels were measured. The HFD feeding resulted in obesity, which was associated with increases in body weight, liver weight, fat pad weight, liver enzymes, and plasma leptin levels with the development of hyperlipidemia. RYR prevented weight gain and fat pad weight in mice fed a HFD. RYR alleviated blood lipid parameters, liver enzymes, and leptin levels, and improved atherogenic index. These findings suggest that RYR has therapeutic potential in treating obesity and hyperlipidemia.
    No preview · Article · Jul 2015 · Journal of medicinal food
  • Sung Tae Kim · S.-R. Cho · Minyung Song · Suk Tai Chang
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    ABSTRACT: Rectangular cellulose microfibers were synthesized by regenerating cellulose from an ionic liquid, l-ethyl-3- methylimidazolium acetate, in a hydrodynamic flow-focusing microfluidic device. This technique is a fast and single-step approach for producing natural polymer microfibers. The dimensions of the cellulose microfibers were readily controlled by a simple variation of the core-sheath flow rate and the viscosity of fluids.
    No preview · Article · Jul 2015 · Polymer Korea
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    ABSTRACT: Objective: To evaluate the differences between early-onset subcortical vascular cognitive impairment (EO-SVCI) and late-onset subcortical vascular cognitive impairment (LO-SVCI) with regard to pathologic burden, structural changes, and cognitive function. Methods: We prospectively recruited 142 patients from a single referral center. Patients were divided into EO-SVCI (n = 30, age at onset <65 years) and LO-SVCI (n = 112, age at onset ≥65 years) groups. All patients underwent neuropsychological tests, 3T brain MRI, and [(11)C] Pittsburgh compound B (PiB)-PET. We compared pathologic burden such as small vessel disease and amyloid burden; structural changes such as structural network, cortical thickness, and hippocampal volume; and cognitive function between EO-SVCI and LO-SVCI. Results: EO-SVCI patients had more lacunes, while LO-SVCI patients had higher PiB standardized uptake value ratios. EO-SVCI patients exhibited more severe structural network disruptions in the frontal area, while LO-SVCI patients exhibited more severe cortical and hippocampal atrophy. Although disease severity did not differ between the 2 groups, frontal-executive dysfunction was more severe in EO-SVCI patients. Conclusions: EO-SVCI patients showed more vascular related factors, while LO-SVCI patients exhibited more Alzheimer disease-related characteristics. The greater number of lacunes in EO-SVCI might account for the more severe frontal network disruption and frontal-executive dysfunction, while the greater amyloid burden in LO-SVCI might account for the more severe cortical and hippocampal atrophy. Our findings suggest that the age at onset is a crucial factor that determines distinct features in SVCI patients, such as pathologic burden, structural changes, and cognitive function.
    No preview · Article · Jul 2015 · Neurology
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    ABSTRACT: Background: Recent advances in resting-state functional MRI have revealed altered functional networks in Alzheimer's disease (AD), especially those of the default mode network (DMN) and central executive network (CEN). However, few studies have evaluated whether small vessel disease (SVD) or combined amyloid and SVD burdens affect the DMN or CEN. Objective: The aim of study was to evaluate whether SVD or combined amyloid and SVD burdens affect the DMN or CEN. Methods: In this cross-sectional study, we investigated the resting-state functional connectivity within DMN and CEN in 37 Pittsburgh compound-B (PiB)(+) AD, 37 PiB(-) subcortical vascular dementia (SVaD), 13 mixed dementia patients, and 65 normal controls. Results: When the resting-state DMN of PiB(+) AD and PiB(-) SVaD patients were compared, the PiB(+) AD patients displayed lower functional connectivity in the inferior parietal lobule while the PiB(-) SVaD patients displayed lower functional connectivity in the medial frontal and superior frontal gyri. Compared to the PiB(-) SVaD or PiB(+) AD, the mixed dementia patients displayed lower functional connectivity within the DMN in the posterior cingulate gyrus. When the resting-state CEN connectivity of PiB(+) AD and PiB(-) SVaD patients were compared, the PiB(-) SVaD patients displayed lower functional connectivity in the anterior insular region. Compared to the PiB(-) SVaD or PiB(+) AD, the mixed dementia patients displayed lower functional connectivity within the CEN in the inferior frontal gyrus. Conclusions: Our findings suggest that in PiB(+) AD and PiB(-) SVaD, there is divergent disruptions in resting-state DMN and CEN. Furthermore, patients with combined amyloid and SVD burdens exhibited more disrupted resting-state DMN and CEN than patients with only amyloid or SVD burden.
    No preview · Article · Jul 2015 · Journal of Alzheimer's disease: JAD
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    ABSTRACT: We conducted a phase 1 clinical trial in nine patients with mild-to-moderate Alzheimer's disease to evaluate the safety and dose-limiting toxicity of stereotactic brain injection of human umbilical cord blood–derived mesenchymal stem cells (hUCB-MSCs).
    Full-text · Article · Jul 2015

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  • No preview · Article · Jul 2015
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    ABSTRACT: Bioorthogonal catalysis broadens the functional possibilities of intracellular chemistry. Effective delivery and regulation of synthetic catalytic systems in cells are challenging due to the complex intracellular environment and catalyst instability. Here, we report the fabrication of protein-sized bioorthogonal nanozymes through the encapsulation of hydrophobic transition metal catalysts into the monolayer of water-soluble gold nanoparticles. The activity of these catalysts can be reversibly controlled by binding a supramolecular cucurbit[7]uril 'gate-keeper' onto the monolayer surface, providing a biomimetic control mechanism that mimics the allosteric regulation of enzymes. The potential of this gated nanozyme for use in imaging and therapeutic applications was demonstrated through triggered cleavage of allylcarbamates for pro-fluorophore activation and propargyl groups for prodrug activation inside living cells.
    No preview · Article · Jun 2015 · Nature Chemistry
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    ABSTRACT: Prestressed concrete (PSC) is one of the most reliable, durable and widely used construction materials, which overcomes the weakness of concrete in tension by the introduction of a prestress force. Smart strands enabling measurement of the prestress force have recently been developed to maintain PSC structures throughout their lifetime. However, the smart strand cannot give a representative indication of the whole prestress force when used in multi-strand systems since each strand sustains a different prestress force. In this paper, the actual distribution of the prestress force in a multi-strand system is examined using elastomagnetic (EM) sensors to develop a method for tracking representative indicators of the prestress force using smart strands.
    Preview · Article · Jun 2015 · Sensors
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    ABSTRACT: Bacterial biofilms are widely associated with persistent infections. High resistance to conventional antibiotics and prevalent virulence makes eliminating these bacterial communities challenging therapeutic targets. We describe here the fabrication of a nanoparticle-stabilized capsule with a multicomponent core for the treatment of biofilms. The peppermint oil and cinnamaldehyde combination that comprises the core of the capsules act as potent antimicrobial agents. An in situ reaction at the oil/water interface between the nanoparticles and cinnamaldehyde structurally augments the capsules to efficiently deliver the essential oil payloads, effectively eradicating biofilms of clinically isolated pathogenic bacteria strains. In contrast to their antimicrobial action, the capsules selectively promoted fibroblast proliferation in a mixed bacteria/mammalian cell system making them promising for wound healing applications.
    No preview · Article · Jun 2015 · ACS Nano

Publication Stats

3k Citations
958.77 Total Impact Points

Institutions

  • 2014-2015
    • Inje University Paik Hospital
      • • Department of Neurosurgery
      • • Department of Radiology
      Sŏul, Seoul, South Korea
  • 2012-2015
    • University of Massachusetts Amherst
      • Department of Chemistry
      Amherst Center, Massachusetts, United States
    • Inje University
      • Department of Medicine and Premedicine
      Kŭmhae, Gyeongsangnam-do, South Korea
    • Chung-Ang University
      • • College of Pharmacy
      • • School of Chemical Engineering and Materials Science
      Sŏul, Seoul, South Korea
  • 2011-2015
    • University of Pittsburgh
      • • Pharmaceutical Sciences
      • • School of Pharmacy
      Pittsburgh, Pennsylvania, United States
    • University of Nebraska at Lincoln
      • Department of Management
      Lincoln, Nebraska, United States
  • 2010-2015
    • Korea Institute of Construction Technology
      Kōyō, Gyeonggi-do, South Korea
    • Woosong University
      Onyang, South Chungcheong, South Korea
    • Konkuk University Medical Center
      • Department of Neurology
      Changnyeong, South Gyeongsang, South Korea
  • 2006-2015
    • Samsung Medical Center
      • • Department of Radiology
      • • Department of Physical and Rehabilitation Medicine
      • • Department of Neurology
      Sŏul, Seoul, South Korea
  • 2005-2015
    • Sungkyunkwan University
      • Department of Radiology
      Sŏul, Seoul, South Korea
  • 2007-2014
    • Washington University in St. Louis
      • • Department of Obstetrics and Gynecology
      • • Department of Anesthesiology
      • • Department of Medicine
      San Luis, Missouri, United States
    • National Fisheries Research and Development Institution
      Sŏul, Seoul, South Korea
    • Korea Institute of Machinery and Materials
      Sŏul, Seoul, South Korea
    • Korea National Police University
      Sŏul, Seoul, South Korea
  • 2002-2014
    • Korea University
      • • College of Medicine
      • • Department of Internal Medicine
      Sŏul, Seoul, South Korea
    • DePaul University
      Chicago, Illinois, United States
  • 2006-2013
    • Hanyang University
      • Department of Biomedical Engineering
      Sŏul, Seoul, South Korea
  • 2009-2010
    • Community Tissue Services
      Fresno, California, United States
    • University of Ulsan
      Ulsan, Ulsan, South Korea
    • Konyang University
      • College of Medicine
      Ronsan, Chungcheongnam-do, South Korea
    • Yonsei University
      • Department of Prosthodontics
      Sŏul, Seoul, South Korea
    • Hyundai Motor Company
      Sŏul, Seoul, South Korea
  • 2008-2009
    • Dongguk University
      Sŏul, Seoul, South Korea
  • 2005-2009
    • Ulsan University Hospital
      Urusan, Ulsan, South Korea
  • 2001-2009
    • Seoul National University
      • • College of Pharmacy
      • • College of Engineering
      • • Division of Chemistry and Molecular Engineering
      Sŏul, Seoul, South Korea
  • 2005-2007
    • Inha University
      • Department of Polymer Science and Engineering
      Chemulpo, Incheon, South Korea
  • 1996-2007
    • LG Electronics
      Sŏul, Seoul, South Korea
  • 2003-2005
    • Konyang University Hospital
      Gaigeturi, Jeju-do, South Korea
    • Inha University Hospital
      Sinhyeon, Gyeongsangnam-do, South Korea
  • 2004
    • Yonsei University Hospital
      Sŏul, Seoul, South Korea
  • 1996-1998
    • University of Cambridge
      • Department of Chemistry
      Cambridge, England, United Kingdom