Seung Hoon Kim

Catholic University of Korea, Sŏul, Seoul, South Korea

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Publications (69)122.47 Total impact

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    ABSTRACT: Although influenza A (H1N1) virus leads to self-limiting illness, co-infection with bacteria may result in cases of severe respiratory failure due to inflammation and necrosis of intra-airway, as pseudomembranous tracheobronchitis. Pseudomembranous tracheobronchitis is usually developed in immunocompromised patients, but it can also occur in immunocompetent patients on a very rare basis. We report a case of pseudomembranous tracheobronchitis complicated by co-infection of inflenaza A and Staphylococcus aureus, causing acute respiratory failure in immunocompetent patients.
    Preview · Article · Oct 2015 · Tuberculosis and Respiratory Diseases
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    ABSTRACT: Mutation-specific antibodies have recently been developed for identification of epidermal growth factor receptor (EGFR) mutations by immunohistochemistry (IHC). This study was designed to investigate whether the type of specimen (biopsy vs. resection) would make a difference in determining mutation status by IHC, and to evaluate whether biopsies are suitable for detection of mutant EGFR protein. IHC was performed using mutation-specific antibodies for E746-A750 deletion (DEL) and L858R point mutation (L858R) in biopsies and tissue microarrays of resected tumors from 154 patients with pulmonary adenocarcinoma. were then compared with DNA sequencing data. Molecular-based assays detected EGFR mutations in 62 patients (40.3%), including 14 (9.1%) with DEL, and 31 (20.1%) with L858R. IHC with two mutation-specific antibodies showed a homogeneous staining pattern, and correctly identified EGFR mutation status in 89% (137/154). Overall (biopsy/resection) sensitivity, specificity, positive predictive value, and negative predictive value were 75.6% (78.3%/72.7%), 94.5% (90.9%/96.3%), 85% (78.3%/88.9%), and 90.4% (90.9%/89.7%), respectively. Our data showed that IHC using EGFR mutation-specific antibodies is useful for detection of EGFR mutations with high specificity and good sensitivity not only for resection specimens but also for biopsy materials. Therefore, IHC using EGFR mutation-specific antibodies may preclude a second biopsy procedure to obtain additional tissues for identification of EGFR mutations by molecular assays in biopsies from advanced cancer, particularly when tumor cells in the samples are limited.
    Preview · Article · Jan 2015 · Cancer Research and Treatment
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    ABSTRACT: This letter presents a multi-rate clock and data recovery circuit realized in a standard 65-nm CMOS technology, which operates from 3.125 Gb/s to 22 Gb/s. In order to cover the wide frequency range, a modified four- stage differential ring VCO is exploited, which provides not only the fast tracking ability from its coarse tuning, but also the precise tra cking from its fine tuning. Also, a voltage-regulated active filter is employed to reduce the ripples of the VCO control voltages. It helps to fasten the lock-in time of the proposed CDR circuit and improve the jitter characteristics against PVT variations. Measurements reveal that the CDR chip demonstrates very wide capture range of 3.125 similar to 22 Gb/ s, 3.3 ps(,rms) data jitter at 20 Gb/s, and 112-mW power dissipation from a single 1.2-V supply. The chip core occupies the area of 0.12 mm(2) only.
    No preview · Article · Nov 2014 · IEICE Electronics Express

  • No preview · Article · Sep 2014
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    ABSTRACT: This paper introduces a four-channel optical receiver array implemented in a standard 1P4M 0.18 mu m CMOS technology for the applications of active optical HDMI cables. Each channel consists of a current-mirror transimpedance amplifier, a five-stage differential limiting amplifier, and an output buffer, demonstrating 81-dB Omega transimpedance gain, 1.8-GHz bandwidth even with 0.5-pF photodiode capacitance, -18.3-dBm optical sensitivity for 10(-12) BER & 0.6-A/ W responsivity, and 51.7-mW power dissipation from a single 1.8-V supply. The whole chip occupies the area of 1.35 x 2.46 mm(2) including pads. The measured eye-diagrams of the array confirms wide and clear eye-openings up to 4.0-Gb/s operations.
    No preview · Article · Jan 2014 · IEICE Electronics Express
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    Young Min Jang · Seung Hoon Kim · Sang Bock Cho · Sung Min Park
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    ABSTRACT: This paper presents multi-channel transimpedance amplifier(TIA) arrays in short-range LADAR systems for unmanned vehicles, by using a 0.18um CMOS technology. Two channel TIA arrays including a voltage-mode INV-TIA and a current-mode CG-TIA are introduced. First, the INV-TIA consists of a inverter stage with a feedback resistor and a CML output buffer with virtual ground so as to achieve low noise, low power, easy current control for gain and impedance. Second, the CG-TIA utilizes a bias from on-chip bandgap reference and exploits a source-follower for high-frequency peaking, yielding 1.26 times smaller chip area per channel than INV-TIA. Post-layout simulations demonstrate that the INV-TIA achieves 57.5-dB transimpedance gain, 340-MHz bandwidth, 3.7-pA/sqrt(Hz) average noise current spectral density, and 2.84mW power dissipation, whereas the CG-TIA obtains 54.5-dB transimpedance gain, 360-MHz bandwidth, 9.17-pA/sqrt(Hz) average noise current spectral density, and 4.24mW power dissipation. Yet, the pulse simulations reveal that the CG-TIA array shows better output pulses in the range of 200-500-Mb/s operations.
    Preview · Article · Dec 2013
  • Xiao Ying · Hanbyul Choi · Seung Hoon Kim · Sung Min Park
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    ABSTRACT: This paper presents a dual-channel current-mode optical receiver array which exploits the modified current-mirror(CM) transimpedance amplifiers and the gain-scaling limiting amplifiers. Each modified CM-TIA consists of a CM input configuration with a local feedback, a single-to-differential conversion circuit, a differential amplifier stage, and a 50Ω output buffer. Since the modified CM input effectively isolates the photodiode capacitance from the bandwidth determination, it provides considerable bandwidth enhancement. Also, the gain-scaling limiting amplifiers employ the Cherry-Hooper topology and the capacitive source-degeneration technique to maintain wide bandwidth. Test chips were fabricated by using a standard 0.18-μm CMOS technology, demonstrating 3.5Gb/s operation speed per channel even with 0.52pF total input parasitic capacitance (including 0.32pF photodiode capacitance), and 87mW power dissipation (including output buffer) in total from a single 1.8V supply.
    No preview · Conference Paper · Nov 2013
  • Saemi Park · Seung Hoon Kim · Tae Kwann Park · Young-Hoon Ohn
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    ABSTRACT: Purpose: To evaluate structural and functional changes in non-pathologic myopic fundus using multifocal electroretinogram (mfERG) and spectral domain-optical coherence tomography (SD-OCT). Methods: A total of 90 myopic subjects underwent mfERG and SD-OCT. The subjects were divided into four groups according to spherical equivalent refractive error: Group 1 (-0.50 to -2.75 D), Group 2 (-3.00 to -5.75 D), Group 3 (-6.00 to -9.75 D), and Group 4 (-10.0 to -15.0 D). Total retinal thickness, photoreceptor retinal thickness (PR), outer nuclear retinal thickness and mid-inner retinal thickness (MIR) were measured using SD-OCT in foveola and two perifoveal retinal regions 2.0 mm nasal and temporal from the foveola. The amplitude and implicit time of N1 and P1 mfERG responses were analyzed using six-concentric-ring grouping. Correlations between each retinal thickness, amplitude, and implicit time among the four myopic groups were analyzed. Results: PR thickness in the foveola and MIR thickness in the perifoveal retina were significantly reduced with increasing myopic refractive errors (p = 0.001, respectively). Significant correlations appeared between N1 amplitude, P1 amplitude, P1 implicit time, and refractive errors (p = 0.001, respectively). Significant correlations appeared between MIR thickness and N1, P1 amplitude (p = 0.001, respectively) as well as N1, P1 implicit time (p = 0.02 and 0.03, respectively) in the perifoveal retina corresponding to ring 4. Conclusions: The correlation between structural and functional changes in myopia should be considered when interpreting retinal structure and function using SD-OCT and mfERG, especially in high myopia.
    No preview · Article · Mar 2013 · Documenta Ophthalmologica

  • No preview · Article · Sep 2012 · Acta ophthalmologica
  • Seung Hoon Kim · Kyung Seek Choi
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    ABSTRACT: To compare the infusion pressure shown by a vitrectomy device with the actual intraocular pressure (IOP) observed during pars plana vitrectomy. Furthermore, we evaluated the effects of variable parameters on the actual IOP during vitrectomy surgery. Porcine eyes were obtained within 24 h of slaughter. Actual IOP was measured by a digital manometer during vitrectomy using the vented gas forced infusion (VGFI) system, as well as the gravity system. We analyzed the actual IOP according to the groups divided by remnant volume of infusion fluid: (500 ml; control group, 250, 125, and 50 ml). Finally, actual IOP was determined after changing variable parameters such as cutting rate, vacuum pressure, and the VGFI setting. Settings for a VGFI system and pressure supplied by a gravity system significantly correlated with actual IOP (r = 0.99, p = 0.0001; r = 0.99, and p = 0.0001). Actual IOP declined with decreasing volume of infusion fluid. If the volume of infusion fluid was <125 ml, actual IOP decreased significantly compared with the control group and the difference in actual IOP reflected a significant difference in the VGFI setting of 30 mmHg. Cutting rate as well as VGFI setting and vacuum pressure affected actual IOP. Infusion pressure shown by the vitrectomy device was similar to actual IOP in porcine eyes. However, volume of infusion fluid and variable parameters could change the actual IOP during pars plana vitrectomy. Our results may help to optimize the ideal parameters such as infusion pressure, vacuum pressure, and cutting rate of vitrectomy systems used to treat vitreoretinal diseases.
    No preview · Article · May 2012 · Current eye research
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    ABSTRACT: To diagnose rectal cancer and monitor treatment response after preoperative concurrent chemoradiotherapy (CCRT) in rectal cancer patients using proton-1 magnetic resonance spectroscopy ((1)H-MRS). We enrolled 134 rectal cancer patients before treatment, of whom 34 underwent preoperative CCRT and follow-up MR spectroscopy before surgery. (1)H-MRS was performed using a six-channel phased-array coil at 3.0 T. We evaluated the presence of a choline peak at 3.2 ppm, and lipid peaks at 0.9 and 1.3 ppm, and glutamine and glutamate peaks at 2.1-2.3 and 2.7 ppm seen at two TEs (40 and 135 ms). We divided MR spectra patterns into two groups (A and B). A choline peak at 3.2 ppm seen in both TEs was characteristic for rectal cancer before treatment. Of 103 patients, 55 (53%) showed an elevated choline peak before treatment (type A). Type A spectra were seen in 68% of patients (23/34) before preoperative CCRT. After CCRT, the choline peak disappeared, resulting in only the lipid peak at 1.3 ppm (type B) in 97% of patients (33/34). We optimized a localized in vivo(1)H-MRS method for detection of rectal adenocarcinoma and monitoring treatment response after preoperative CCRT. The method appears to be a promising and feasible noninvasive modality.
    No preview · Article · Apr 2012 · Magnetic Resonance Imaging
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    Seung Hoon Kim · Sun Woong Kim · Bum-Tae Kim · Jee Ho Chang
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    ABSTRACT: Oculomotor disturbance is the common manifestation of intracavernous carotid aneurysm cases. Intracavernous carotid aneurysms causing compressive optic neuropathy with no oculomotor disturbance are relatively rare due to their anatomical characteristics. We experienced a case of intracavernous carotid aneurysm which resulted in a shifted supraclinoid segment of the internal carotid artery, presenting with visual loss and visual field defect with no oculomotor disturbance.
    Preview · Article · Jan 2012 · Journal of the Korean Ophthalmological Society
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    Seung Hoon Kim · Joo Youn Park · Tae Kwann Park · Young-Hoon Ohn
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    ABSTRACT: To investigate the correlation of macular retinal thickness and refractive error using spectral-domain optical coherence tomography (SD-OCT).
    Preview · Article · Nov 2011 · Journal of the Korean Ophthalmological Society
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    ABSTRACT: To report on the anatomical and functional changes to the macula in nine patients suffering from commotio retinae not accompanied by any other types of traumatic retinopathy. Nine injured eyes with commotio retinae were evaluated soon after ocular trauma with ophthalmic examination, including Spectral-domain optical coherence tomography (SD-OCT). In 12 eyes of 6 patients, Humphrey visual field (HVF) and multifocal electroretinogram (mfERG) were performed. Re-examinations were periodically performed for a mean of 26 days. Data from 9 injured eyes were collected and compared to data collected from the 9 non-affected eyes of the same patients. SD-OCT revealed no significant differences in the foveal thickness and total macular volume between traumatized and intact eyes in all 9 patients. Only 3 out of the 9 injured eyes showed abnormal findings in SD-OCT images such as discontinuity of the inner/outer segment (IS/OS) junction or abnormal hyper-reflectivity from the IS/OS and retinal pigment epithelium (RPE) lines in the macula. HVF and mfERG results did not show any functional deterioration in the injured eyes compared with intact eyes. During follow-up, the commotio retinae resolved in all 9 eyes. The changes to the outer retinal region detected in 3 patients by SD-OCT were also resolved. Acute retinal changes in commotio retinae, not associated with other retinal pathologies, were resolved without histological and functional sequelae. In a few cases of commotio retinae, SD-OCT revealed transient abnormalities mainly observed at the IS/OS and RPE complexes.
    Full-text · Article · Aug 2011 · Korean Journal of Ophthalmology
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    Joo Youn Park · Seung Hoon Kim · Tae Kwann Park · Young-Hoon Ohn
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    ABSTRACT: To evaluate the changes in multifocal electroretinogram (mfERG) and optical coherence tomography (OCT) after intravitreal bevacizumab injection in the treatment of age-related macular degeneration (AMD). Twenty-one eyes with choroidal neovascularization secondary to AMD were studied before and after intravitreal bevacizumab injection for best corrected visual acuity (BCVA), OCT, and mfERG. The BCVA improved, while central macular thickness and total macular volume in OCT decreased after intravitreal bevacizumab injection (p = 0.03, 0.01, and 0.01, respectively). In mfERG, the amplitude of P1, and implicit time of P1 and N1 indicated a statistically significant improvement of retinal response after intravitreal bevacizumab injection. There is a potential role for mfERG in evaluating the effect on retinal function of intravitreal bevacizumab injection.
    Preview · Article · Jun 2011 · Korean Journal of Ophthalmology
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    Seung Hoon Kim · Kyung Seek Choi · Sung Jin Lee
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    ABSTRACT: To evaluate the changes in macular thickness with regard to age and gender in normal subjects with emmetropia using spectral domain optical coherence tomography.
    Preview · Article · Mar 2011 · Journal of the Korean Ophthalmological Society
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    ABSTRACT: This study was designed to compare the diagnostic performance of gadoxetic acid-enhanced magnetic resonance imaging (MRI) with gadobenate dimeglumine-enhanced MRI for preoperatively detecting hepatocellular carcinoma (HCC). Eighteen consecutive patients (17 men and one woman, age range: 31-73 years) with 22 HCCs underwent examinations with gadoxetic acid enhanced MRI and gadobenate dimeglumine-enhanced MRI on a 3.0-Tesla unit. The diagnosis of HCC was established after surgical resection and pathological conformation. Three observers independently reviewed each MR image in a random order on a tumor-by-tumor basis. The diagnostic accuracy of these techniques for the detection of HCC was assessed by performing an alternative free-response receiver operating characteristic (ROC) analysis. The sensitivity and positive predictive values were evaluated. The average value of the area under the ROC curve (Az) for gadoxetic acid enhanced MRI (0.887) was not significantly different from the Az (0.899) for gadobenate dimeglumine-enhanced MRI (p > 0.05). The overall sensitivities of gadoxetic acid enhanced MRI and gadobenate dimeglumine-enhanced MRI were 80% and 83%, respectively, with no significant difference (p > 0.05). The differences of the positive predictive values for the two contrast agents for each observer were not statistically significant (p > 0.05). The diagnostic performance of gadoxetic acid-enhanced MRI and gadobenate dimeglumine-enhanced MRI for preoperatively detecting HCC is quite similar.
    Preview · Article · Jun 2010 · Korean journal of radiology: official journal of the Korean Radiological Society
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    ABSTRACT: We compared the diagnostic performance of gadoxetic acid-enhanced MRI with that of triple-phase 16-, 40-, and 64-MDCT in the preoperative detection of hepatocellular carcinoma (HCC). Sixty-two consecutively registered patients (54 men, eight women; age range, 31-67 years) with 83 HCCs underwent triple-phase (arterial, portal venous, equilibrium) CT at 16-, 40-, or 64-MDCT and gadoxetic acid-enhanced 3-T MRI. The diagnosis of HCC was established after surgical resection. Three observers independently and randomly reviewed the MR and CT images on a tumor-by-tumor basis. The diagnostic accuracy of these techniques in the detection of HCC was assessed with alternative free response receiver operating characteristic (ROC) analysis. Sensitivity, positive and negative predictive values, and sensitivity according to tumor size were evaluated. For each observer, the areas under the ROC curve were 0.971, 0.959, and 0.967 for MRI and 0.947, 0.950, and 0.943 for CT. The differences were not statistically significant between the two techniques for each observer (p > 0.05). The differences in sensitivity and positive and negative predictive values between the two techniques for each observer were not statistically significant (p > 0.05). Among 10 HCCs 1 cm in diameter or smaller, each of the observers detected seven tumors with MRI. With CT, one observer detected five, one observer detected four, and one observer detected three HCCs with no statistically significant difference (p > 0.05). Gadoxetic acid-enhanced MRI and triple-phase MDCT have similar diagnostic performance in the preoperative detection of HCC, but MRI may be better than MDCT in the detection of HCC 1 cm in diameter or smaller.
    No preview · Article · Jul 2009 · American Journal of Roentgenology
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    ABSTRACT: Purpose The aim of this study was to describe pancreatic involvement in von Hippel-Lindau (VHL) disease and to document the changes that occur in pancreatic lesions. Methods We retrospectively analyzed the medical records and CT scans of 18 VHL patients who were diagnosed between 1994 and 2007 at the Samsung Medical Center. The clinical history with a detailed family history, biochemical test results, and imaging studies of the pancreas, adrenal glands, and kidneys were reviewed. Genetic analysis was performed in 12 patients. The changes in pancreatic lesions, such as an increase in cystic lesions, calcifications, and dilatation of the pancreatic duct, were analyzed in patients who had CT scans at least 1 year apart. Results Pancreatic lesions existed in 89% (16/18) of the patients. All 16 patients had multiple cystic lesions. Two patients had co-existing neuroendocrine tumors (NET), and two patients had co-existing serous cystadenomas (SCA). At least one of three features of pancreatic lesions (cystic lesions, calcifications, and dilatation of the pancreatic duct) progressed in all nine patients who had CT scans 1 year apart. Conclusion Pancreatic involvement in VHL disease was relatively common in Korean patients. The most common type of pancreatic involvement was a multiple cystic lesion. NET and SCA existed in approximately 10% of VHL patients with pancreatic involvement. Pancreatic lesions in VHL disease progressed, at least according to radiological images.
    Preview · Article · May 2009 · Journal of Gastroenterology
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    ABSTRACT: To compare the in vivo gastric injury observed during radiofrequency (RF) ablation of the liver abutting the stomach before and after the intragastric administration of chilled saline. Twenty RF ablation zones were created in the livers of 10 pigs with a 1-cm-exposed active tip of an internally cooled electrode under ultrasound guidance for 10 min. Ten RF ablation zones were created before (non-saline group) and after (saline group) the intragastric administration of approximately 1000 mL of chilled saline, and 20 RF ablation zones were made in the posterior part of the left lobe abutting the stomach. The frequency and severity of the thermal injury observed in the stomach of the two groups were compared histologically. All the resected gastric specimens showed thermal injuries of varying degrees of severity. The largest diameter of the gastric injury was significantly smaller in the saline group (mean 1.5 cm; range 1.3-1.8 cm) than in the non-saline group (mean 2.1cm; range 1.8-2.4 cm) (p=0.000). The saline group showed significantly less thermal injury to the muscular layer of the gastric wall by the histopathology (p=0.033). The intragastric administration of chilled saline might be a useful technique for reducing the severity of gastric injury during RF ablation of the liver abutting the stomach.
    No preview · Article · Sep 2008 · European journal of radiology

Publication Stats

2k Citations
122.47 Total Impact Points

Institutions

  • 2001-2015
    • Catholic University of Korea
      • • Department of Internal Medicine
      • • Research Institute of Immunobiology
      Sŏul, Seoul, South Korea
    • Inje University
      Kŭmhae, South Gyeongsang, South Korea
  • 2013-2014
    • Ewha Womans University
      • Department of Electronics Engineering
      Sŏul, Seoul, South Korea
  • 2011-2013
    • Soonchunhyang University
      • College of Medicine
      Onyang, Chungcheongnam-do, South Korea
  • 2002-2012
    • Sungkyunkwan University
      • • Samsung Medical Center
      • • Department of Radiology
      Sŏul, Seoul, South Korea
  • 2002-2008
    • Samsung Medical Center
      • Department of Radiology
      Sŏul, Seoul, South Korea
  • 2004
    • Seonam University
      Onyang, South Chungcheong, South Korea