Hyung-Sun Kim

Hyung-Sun Kim

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Hyung-Sun Kim

Animal model research group, Korea Institute of Toxicology, Jeongup 53212, Korea

Research Focus & Metrics

Academic Career Length

19Years (2008-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 February 2011 in Journal of Clinical Microbiology
Verified
Journal Article
Open access
PDF file
DKDong-Min Kim
Dong-Min Kim
GPGeon Park
Geon Park
HKHyong Sun Kim
Hyong Sun Kim
JLJoo Young Lee
Joo Young Lee
GNGanesh Prasad Neupane
Ganesh Prasad Neupane
JSJohn Stenos
John Stenos
Orientia tsutsugamushi is the causative agent of scrub typhus. For the diagnosis of scrub typhus, we investigated the performances of conventional PCR (C-PCR), nested PCR (N-PCR), and real-time quantitative PCR (Q-PCR) targeting the O. tsutsugamushi -specific 47-kDa gene. To compare the detection sensitivities of the three techniques, we used two template systems that used plasmid DNA (plasmid detection sensitivity), including a partial region of the 47-kDa gene, and genomic DNA (genomic detection sensitivity) from a buffy coat sample of a single patient. The plasmid detection sensitivities of C-PCR, N-PCR, and Q-PCR were 5 × 10 4 copies/μl, 5 copies/μl, and 50 copies/μl, respectively. The results of C-PCR, N-PCR, and Q-PCR performed with undiluted genomic DNA were negative, positive, and positive, respectively. The genomic detection sensitivities of N-PCR and Q-PCR were 64-fold and 16-fold (crossing point [Cp], 37.7; 426 copies/μl), respectively. For relative quantification of O. tsutsugamushi bacteria per volume of whole blood, we performed real-time DNA PCR analysis of the human GAPDH gene, along with the O. tsutsugamushi 47-kDa gene. At a 16-fold dilution, the copy number and genomic equivalent (GE) of GAPDH were 1.1 × 10 5 copies/μl (Cp, 22.64) and 5.5 × 10 4 GEs/μl, respectively. Therefore, the relative concentration of O. tsutsugamushi at a 16-fold dilution was 0.0078 organism/one white blood cell (WBC) and 117 organisms/μl of whole blood, because the WBC count of the patient was 1.5 × 10 4 cells/μl of whole blood. The sensitivities of C-PCR, N-PCR, and Q-PCR performed with blood samples taken from patients within 4 weeks of onset of fever were 7.3% (95% confidence interval [CI], 1.6 to 19.9), 85.4% (95% CI, 70.8 to 94.4), and 82.9% (95% CI, 67.9 to 92.8), respectively. All evaluated assays were 100% specific for O. tsutsugamushi . In conclusion, given its combined sensitivity, specificity, and speed, Q-PCR is the preferred assay for the diagnosis of scrub typhus.

1 January 2012 in Journal of Korean Neurosurgical Society
Verified
Journal Article
Open access
PDF file
JKJin-Myung Kim
Jin-Myung Kim
Dong  Ah ShinDong Ah Shin
Dong Ah Shin
DBDong-Hak Byun
Dong-Hak Byun
HKHyung-Sun Kim
Hyung-Sun Kim
SKSohee Kim
Sohee Kim
HKHyoung-Ihl Kim
Hyoung-Ihl Kim
The purpose of this study is to find the optimal stiffness and volume of bone cement and their biomechanical effects on the adjacent vertebrae to determine a better strategy for conducting vertebroplasty. A three-dimensional finite-element model of a functional spinal unit was developed using computed tomography scans of a normal motion segment, comprising the T11, T12 and L1 vertebrae. Volumes of bone cement, with appropriate mechanical properties, were inserted into the trabecular core of the T12 vertebra. Parametric studies were done by varying the volume and stiffness of the bone cement. When the bone cement filling volume reached 30% of the volume of a vertebral body, the level of stiffness was restored to that of normal bone, and when higher bone cement exceeded 30% of the volume, the result was stiffness in excess of that of normal bone. When the bone cement volume was varied, local stress in the bony structures (cortical shell, trabecular bone and endplate) of each vertebra monotonically increased. Low-modulus bone cement has the effect of reducing strain in the augmented body, but only in cases of relatively high volumes of bone cement (>50%). Furthermore, varying the stiffness of bone cement has a negligible effect on the stress distribution of vertebral bodies. The volume of cement was considered to be the most important determinant in endplate fracture. Changing the stiffness of bone cement has a negligible effect on the stress distribution of vertebral bodies.

1 September 2008 in Journal of Clinical Microbiology
Verified
Journal Article
Closed access
HKHyong Sun Kim
Hyong Sun Kim
DKDong-Min Kim
Dong-Min Kim
GNGanesh Prasad Neupane
Ganesh Prasad Neupane
YLYu-Mi Lee
Yu-Mi Lee
NYNam-Woong Yang
Nam-Woong Yang
SLSun Hee Lee
Sun Hee Lee
We conducted a prospective study to target toxR in the blood of patients with skin and soft tissue infections who were admitted to four tertiary hospitals to assess the clinical usefulness of real-time quantitative PCR (Q-PCR) as a diagnostic technique. We performed conventional PCR (C-PCR), nested PCR (N-PCR), and Q-PCR assays and compared the results to those obtained using the “gold standard” of microbiological culture. The lower detection limit for the Q-PCR assay was 5 × 10 0 copies/μl. By use of blood samples of patients with skin and soft tissue infections, the sensitivities of the C-PCR and N-PCR assays against the target toxR gene of V. vulnificus as diagnostic tools were determined to be 45% and 86%, respectively. The C-PCR and N-PCR assays had specificities of 100% and 73%, respectively. When we adopted a crossing-point (cp) cutoff value of <38 cp as a positive result, the Q-PCR assay had 100% sensitivity and specificity. Q-PCR to detect V. vulnificus -specific genes is not only the most sensitive and specific of the techniques but also the most rapid diagnostic method. Therefore, the appropriate application of the Q-PCR assay using blood is useful for the rapid diagnosis and subsequent treatment of V. vulnificus sepsis.

6 October 2016 in Biomedical Optics Express
Verified
Journal Article
Open access
PDF file
YSYounghoon Shin
Younghoon Shin
MYMinsu Yoo
Minsu Yoo
HKHyung-Sun Kim
Hyung-Sun Kim
SNSung-Ki Nam
Sung-Ki Nam
HKHyoung-Ihl Kim
Hyoung-Ihl Kim
HKHYUK SANG KWON
HYUK SANG KWON
Understanding light intensity and temperature increase is of considerable importance in designing or performing in vivo optogenetic experiments. Our study describes the optimal light power at target depth in the rodent brain that would maximize activation of light-gated ion channels while minimizing temperature increase. Monte Carlo (MC) simulations of light delivery were used to provide a guideline for suitable light power at a target depth. In addition, MC simulations with the Pennes bio-heat model using data obtained from measurements with a temperature-measuring cannula having 12.3 mV/°C of thermoelectric sensitivity enabled us to predict tissue heating of 0.116 °C/mW on average at target depth of 563 μm and specifically, a maximum mean plateau temperature increase of 0.25 °C/mW at 100 μm depth for 473 nm light. Our study will help to improve the design and performance of optogenetic experiments while avoiding potential over- and under-illumination.

29 January 2014 in Journal of Cerebral Blood Flow & Metabolism
Verified
Journal Article
Open access
HKHyung-Sun Kim
Hyung-Sun Kim
DKDonghyeon Kim
Donghyeon Kim
RKRa Gyung Kim
Ra Gyung Kim
JKJin-Myung Kim
Jin-Myung Kim
ECEuiheon Chung
Euiheon Chung
HKHyoung-Ihl Kim
Hyoung-Ihl Kim
We present a new method for inducing a circumscribed subcortical capsular infarct (SCI), which imposes a persistent motor impairment in rats. Photothrombotic destruction of the internal capsule (IC) was conducted in Sprague Dawley rats (male; n=38). The motor performance of all animals was assessed using forelimb placing, forelimb use asymmetry, and the single pellet reaching test. On the basis of the degree of motor recovery, rats were subdivided into either the poor recovery group (PRG) or the moderate recovery group (MRG). Imaging assessment of the impact of SCI on brain metabolism was performed using 2-deoxy-2-[18F]-fluoro-D-glucose ([18F]-FDG) microPET (positron emission tomography). Photothrombotic lesioning using low light energy selectively disrupted circumscribed capsular fibers. The MRG showed recovery of motor performance after 1 week, but the PRG showed a persistent motor impairment for >3 weeks. Damage to the posterior limb of the IC (PLIC) is more effective for producing a severe motor deficit. Analysis of PET data revealed decreased regional glucose metabolism in the ipsilesional motor and bilateral sensory cortex and increased metabolism in the contralesional motor cortex and bilateral hippocampus during the early recovery period after SCI. Behavioral, histologic, and functional imaging findings support the usefulness of this novel SCI rat model for investigating motor recovery.

29 October 2014 in Journal of Cerebral Blood Flow & Metabolism
Verified
Journal Article
Open access
DKDonghyeon Kim
Donghyeon Kim
RKRa Gyung Kim
Ra Gyung Kim
HKHyung-Sun Kim
Hyung-Sun Kim
JKJin-Myung Kim
Jin-Myung Kim
Sung Chan JunSung Chan Jun
Sung Chan Jun
HKHyoung-Ihl Kim
Hyoung-Ihl Kim
Strokes attributable to subcortical infarcts have been increasing recently in elderly patients. To gain insight how this lesion influences the motor outcome and responds to rehabilitative training, we used circumscribed photothrombotic capsular infarct models on 36 Sprague-Dawley rats (24 experimental and 12 sham-operated). We used 2-deoxy-2-[18F]-fluoro-D-glucose-micro positron emission tomography (FDG-microPET) to assess longitudinal changes in resting-state brain activity (rs-BA) and daily single-pellet reaching task (SPRT) trainings to evaluate motor recovery. Longitudinal FDG-microPET results showed that capsular infarct resulted in a persistent decrease in rs-BA in bilateral sensory and auditory cortices, and ipsilesional motor cortex, thalamus, and inferior colliculus ( P<0.0025, false discovery rate (FDR) q<0.05). The decreased rs-BA is compatible with diaschisis and contributes to manifest the malfunctions of lesion-specific functional connectivity. In contrast, capsular infarct resulted in increase of rs-BA in the ipsilesional internal capsule, and contralesional red nucleus and ventral hippocampus in recovery group ( P<0.0025, FDR q<0.05), implying that remaining subcortical structures have an important role in conducting the recovery process in capsular infarct. The SPRT training facilitated motor recovery only in rats with an incomplete destruction of the posterior limb of the internal capsule (PLIC) (Pearson's correlation, P<0.05). Alternative therapeutic interventions are required to enhance the potential for recovery in capsular infarct with complete destruction of PLIC.