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Search Results: 1 - 10 of 3154 matches for " Oh Kwang "
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Polymyxin B Alleviates Angiotensin II-Induced Stress Fiber Formation and Cellular Hypertrophy  [PDF]
Kwang-Seok Oh, Jeong Hyun Lee, Byung Koo Oh, Jihye Mun, Byung Kil Park, Byung Ho Lee
Pharmacology & Pharmacy (PP) , 2014, DOI: 10.4236/pp.2014.59101
Abstract:

Polymyxin B is widely used antibiotic in the clinic for resistant Gram-negative infections. In addition, polymyxin B-immobilized hemoperfusion cartridge has been used for endotoxin removal therapy in patients with septic shock. The aim of this study was to investigate the anti-fibrotic and anti-cellular hypertrophic effects of polymyxin B, and further to explore its possible mechanism. Polymyxin B (3, 10 μM) significantly inhibited stress fiber formation induced by angiotensin II (Ang II) in rat heart-derived H9c2 cells. Furthermore, polymyxin B (1 - 10 μM) showed a potent inhibitory effect on Ang II-induced cellular hypertrophy in H9c2 cells. Under the mechanism study, the inhibitory activities of polymyxin B against kinases involved in cellular hypertrophy such as AKT1, CAMK, GRK5, GSK3β, MLCK, PKC, PKD2, AMPK, ROCK2, p70S6K, SGK1were evaluated. Polymyxin B possesses a potent G protein related kinase 5 (GKR5) inhibitory activity with IC50 value of 1.1 μM, and has an ATP non-competitive inhibitory mode. Taken together, these results indicate that polymyxin B alleviates Ang II-induced stress fiber formation and cellular hypertrophy, and propose that one mechanism underlying these effects involves inhibition of the GRK5 pathway.

Three-level anterior cervical discectomy and fusion in elderly patients with wedge shaped tricortical autologous graft: A consecutive prospective series
Lee Suk,Oh Kwang,Yoon Kwang,Lee Sung
Indian Journal of Orthopaedics , 2008,
Abstract: Background: Treatment of multilevel cervical spondylotic myelopathy/radiculopathy is a matter of debate, more so in elderly patients due to compromised physiology. We evaluated the clinical and radiological results of cervical fusion, using wedge-shaped tricortical autologous iliac graft and Orion plate for three-level anterior cervical discectomy in elderly patients. Materials and Methods: Twelve elderly patients with mean age of 69.7 years (65-76 years) were treated between April 2000 and March 2005, for three-level anterior cervical discectomy and fusion, using wedge-shaped tricortical autologous iliac graft and Orion plate. Outcome was recorded clinically according to Odom′s criteria and radiologically in terms of correction of lordosis angle and intervertebral disc height span at the time of bony union. The mean follow-up was 29.8 months (12-58 months). Results: All the patients had a complete recovery of clinical symptoms after surgery. Postoperative score according to Odom′s criteria was excellent in six patients and good in remaining six. Bony union was achieved in all the patients with average union time of 12 weeks (8-20 weeks). The mean of sum of three segment graft height collapse was 2.50 mm (SD = 2.47). The average angle of lordosis was corrected from 18.2° (SD = 2.59°) preoperatively to 24.9° (SD = 4.54°) at the final follow-up. This improvement in the radiological findings is statistically significant (P < 0.05). Conclusion: Cervical fusion with wedge-shaped tricortical autologous iliac graft and Orion plate for three-level anterior cervical discectomy is an acceptable technique in elderly patients. It gives satisfactory results in terms of clinical outcome, predictable early solid bony union, and maintenance of disc space height along with restoration of cervical lordosis.
A new mode of clinical failure of porous tantalum rod
Oh Kwang-Jun,Pandher Dilbans
Indian Journal of Orthopaedics , 2010,
Abstract: The area of osteonecrosis of the head of femur affected by the disease process varies from a small localized lesion to a global lesion. Without specific treatment 80% of the clinically diagnosed cases will progress, and most will eventually require arthroplasty. Therefore the goal is to diagnose and treat the condition in the earliest stage. A number of surgical procedures have been described to retard or prevent progression of the disease and to preserve the femoral head. An implant made of porous tantalum has been developed to function as a structural graft to provide mechanical support to the subchondral plate of the necrotic femoral head, and possibly allow bone growth into the avascular region. Porous tantalum implant failure with associated radiological progression of the disease is reported in the literature; however, there is no report of clinical failure of the implant without radiological progression of the disease. We report a case of clinical failure of porous tantalum implant, seven months after surgery without any radiological progression of the disease, and with histopathological evidence of new bone formation around the porous tantalum implant. The patient was succesfully treated by total hip arthroplasty.
Optimal codes in deletion and insertion metric
Hyun Kwang Kim,Joon Yop Lee,Dong Yeol Oh
Mathematics , 2008,
Abstract: We improve the upper bound of Levenshtein for the cardinality of a code of length 4 capable of correcting single deletions over an alphabet of even size. We also illustrate that the new upper bound is sharp. Furthermore we will construct an optimal perfect code capable of correcting single deletions for the same parameters.
Structures and lower bounds for binary covering arrays
Soohak Choi,Hyun Kwang Kim,Dong Yeol Oh
Mathematics , 2011,
Abstract: A $q$-ary $t$-covering array is an $m \times n$ matrix with entries from $\{0, 1, ..., q-1\}$ with the property that for any $t$ column positions, all $q^t$ possible vectors of length $t$ occur at least once. One wishes to minimize $m$ for given $t$ and $n$, or maximize $n$ for given $t$ and $m$. For $t = 2$ and $q = 2$, it is completely solved by R\'enyi, Katona, and Kleitman and Spencer. They also show that maximal binary 2-covering arrays are uniquely determined. Roux found the lower bound of $m$ for a general $t, n$, and $q$. In this article, we show that $m \times n$ binary 2-covering arrays under some constraints on $m$ and $n$ come from the maximal covering arrays. We also improve the lower bound of Roux for $t = 3$ and $q = 2$, and show that some binary 3 or 4-covering arrays are uniquely determined.
Construction of optimal codes in deletion and insertion metric
Hyun Kwang Kim,Joon Yop Lee,Dong Yeol Oh
Mathematics , 2010,
Abstract: We improve Levenshtein's upper bound for the cardinality of a code of length four that is capable of correcting single deletions over an alphabet of even size. We also illustrate that the new upper bound is sharp. Furthermore we construct an optimal perfect code that is capable of correcting single deletions for the same parameters.
Development of Three Dimensional Automatic Body Fat Measurement Software from CT, and Its Validation and Evaluation  [PDF]
Young Jae Kim, Jun Yong Jeong, Su Youn Nam, Min Ju Kim, Jae Hwan Oh, Kwang Gi Kim, Dae Kyung Sohn
Journal of Biomedical Science and Engineering (JBiSE) , 2015, DOI: 10.4236/jbise.2015.810063
Abstract: Abdominal obesity describes the accumulation of excessive fat in the abdomen. It is known that depending on its distribution, visceral obesity presents a greater danger to health than subcutaneous obesity. To properly prevent and treat visceral obesity, accurate evaluation methods are necessary, and hence quantitative VAT estimation is extremely important. CT scans are the most accurate method for estimating VAT, but it requires a great deal of time and effort, limiting its use in studying or evaluating obesity in patients. This paper proposed automatic measurement software that could quickly differentiate between and measure VAT and SAT. The method was verified using a total of 100 abdominal CT data values; this paper measured the SAT and VAT in the entire abdomen using the automatic measurement software. Additionally, through a comparative evaluation between the automated measurements and manual measurements such as BMI and waist circumference, clinical reliability and viability were validated and evaluated. Between automated measurements and manual measurements, the TAT (r = 0.995, p = 0.01), SAT (r = 0.987, p = 0.01) and VAT (r = 0.993, p = 0.01) showed high correlation. Using BMI as the main metric, the TAT for automated measurements (r = 0.674, p = 0.01) and the TAT for manual measurements (r = 0.703, p = 0.01) showed the strongest correlation. When using waist circumference, the VAT for automated measurements (r = 0.826, p = 0.01) and the VAT for manual measurements (r = 0.822, p = 0.01) showed the strongest correlation. With these results, the reliability and viability of the automatic measurement software were confirmed. The software is expected to help greatly in reducing the time and in providing objective data of VAT measurements from CT scans for clinical research.
The determinants of stroke phenotypes were different from the predictors (CHADS2 and CHA2DS2-VASc) of stroke in patients with atrial fibrillation: a comprehensive approach
Semi Oh, Suk Kim, Soo-Kyoung Ryu, Gyeong-Moon Kim, Chin Chung, Kwang Lee, Oh Bang
BMC Neurology , 2011, DOI: 10.1186/1471-2377-11-107
Abstract: We analyzed data pertaining to consecutive AF patients admitted over a 6-year period with acute MCA territory infarcts. We divided the patients according to DWI (diffusion-weighted imaging) lesion volumes and patterns, and the relationship between stroke predictors (the CHADS2 and CHA2DS2-VASc score), systemic, and local factors and each stroke phenotype were then evaluated.The stroke phenotypes varied among 231 patients (admission INR median 1.06, interquartile range (IQR) 1.00-1.14). Specifically, (1) the DWI lesion volumes ranged from 0.04-338.62 ml (median 11.86 ml; IQR, 3.07-44.20 ml) and (2) 46 patients had a territorial infarct pattern, 118 had a lobar/deep pattern and 67 had a small scattered pattern. Multivariate testing revealed that the CHADS2 and CHA2DS2-VASc score were not related to either stroke phenotype. Additionally, the prior use of antiplatelet agents was not related to the stroke phenotypes. Congestive heart failure and diastolic dysfunction were not associated with stroke phenotypes.The results of this study indicated that the determinants of stroke phenotypes were different from the predictors (i.e., CHADS2 and CHA2DS2-VASc score) of stroke in patients with AF.Atrial fibrillation (AF) affects 3% to 5% of the population older than 65 years of age [1] and is a leading cause of fatal ischemic stroke [2,3]. Stroke in patients with AF is generally more severe and the outcome is markedly poorer than in patients with sinus rhythm [4]. Adjusted-dose warfarin is highly effective (~60% reduction), and aspirin is modestly effective (~20% reduction) for the prevention of stroke in AF [5,6]. Moreover, international normalized ratio (INR) levels at the time of stroke were recently reported to be associated with infarct volumes [7].However, the factors affecting stroke phenotypes are unknown among AF patients. Several studies have suggested that infarct patterns are better delineated by DWI than other imaging modalities, are correlated with the underlying st
A novel family VII esterase with industrial potential from compost metagenomic library
Chul-Hyung Kang, Ki-Hoon Oh, Mi-Hwa Lee, Tae-Kwang Oh, Bong Kim, Jung- Yoon
Microbial Cell Factories , 2011, DOI: 10.1186/1475-2859-10-41
Abstract: The estCS2 sequence encodes a protein of 570 amino acid residues, with a predicted molecular mass of 63 kDa, and based on amino acid identity it most closely matches (45%) the carboxylesterase from Haliangium ochraceum DSM 14365. EstCS2 belong to family VII, according to the lipolytic enzyme classification proposed by Arpigny and Jaeger, and it retains the catalytic triad Ser245-Glu363-His466 that is typical of an α/β hydrolase. The Ser245 residue in the catalytic triad of EstCS2 is located in the consensus active site motif GXSXG. The EstCS2 exhibits strong activity toward p-nitrophenyl caproate (C6), and it is stable up to 60°C with an optimal enzymatic activity at 55°C. The maximal activity is observed at pH 9, and it remains active between pH 6-10. EstCS2 shows remarkable stability in up to 50% (v/v) dimethyl sulfoxide (DMSO) or dimethylformamide (DMF). The enzyme has the ability to cleave sterically hindered esters of tertiary alcohol, as well as to degrade polyurethanes, which are widely used in various industries.The high stability of EstCS2 in organic solvents and its activity towards esters of ketoprofen and tertiary alcohols, and in polyurethane suggests that it has potential uses for many applications in biotransformation and bioremediation.Discovering microorganisms and their encoded enzymes, and characterizing their interactions, are one of the main purposes in studying microbial diversity. However, it is commonly thought that only 1-10% of the total microorganisms in most environmental samples can be cultured under laboratory conditions. The study of those remaining, known as "unculturables," is important to understand the genetic diversity, population structure, and ecological roles of microbes and to find ways of utilizing them as a novel source of molecules with unique properties [1]. In recent decades, the investigation by function- and sequence- based screening of the entire microbial genome collected directly from a specific environment, the so-c
Staging of Alzheimer's Pathology in Triple Transgenic Mice: A Light and Electron Microscopic Analysis
Kwang-Jin Oh,Sylvia E. Perez,Sarita Lagalwar,Laurel Vana,Lester Binder,Elliott J. Mufson
International Journal of Alzheimer's Disease , 2010, DOI: 10.4061/2010/780102
Abstract: The age-related pathological cascade underlying intraneuronal tau formation in 3xTg-AD mice, which harbor the human , , and gene mutations, remains unclear. At 3 weeks of age, AT180, Alz50, MC1, AT8, and PHF-1 intraneuronal immunoreactivity appeared in the amygdala and hippocampus and at later ages in the cortex of 3xTg-AD mice. AT8 and PHF-1 staining was fixation dependent in young mutant mice. 6E10 staining was seen at all ages. Fluorescent immunomicroscopy revealed CA1 neurons dual stained for 6E10 and Alz50 and single Alz50 immunoreactive neurons in the subiculum at 3 weeks and continuing to 20 months. Although electron microscopy confirmed intraneuronal cytoplasmic Alz50, AT8, and 6E10 reaction product in younger 3xTg-AD mice, straight filaments appeared at 23 months of age in female mice. The present data suggest that other age-related biochemical mechanisms in addition to early intraneuronal accumulation of 6E10 and tau underlie the formation of tau filaments in 3xTg-AD mice. 1. Introduction During the last several years numerous transgenic animal models of Alzheimer’s disease (AD) have been engineered to examine the effects of the two major AD neuropathological hallmarks, amyloid plaques, and neurofibrillary tangles (NFT) on neurodegeneration. The vast majority of these AD transgenic mice overexpress a mutant human amyloid-beta (A ) precursor protein (APP) gene alone or in combination with a mutated presenilin (PS) gene resulting in the presence of brain extracellular amyloid plaques, which are mainly formed by the accumulation of insoluble A species [1–6]. Since overexpression of amyloid-beta peptide did not recapitulate all of the neuropathological features of AD, additional models were created adding mutant tau transgenes. For example, to further evaluate the pathogenic mechanisms underlying NFT formation, transgenic mouse models have been generated to harbor a mutant human tau gene found in frontotemporal dementia or Pick’s disease (P301L or P301S). These mutant mouse models display NFT-like structures consisting of abnormal cytoskeletal tau protein aggregates in the central and peripheral nervous systems [4, 7–10]. Recently, a triple transgenic mouse (3xTg-AD) harboring the human , , and gene mutations was developed, displaying accumulation of both intracellular A and tau in an age-dependent manner within the cortex, hippocampus, and amygdala [11–14], and to a lesser degree, in the brainstem [15]. Immunohistochemical studies using immersion-fixed 3xTg-AD mouse tissue have shown that intracellular A precedes the appearance of tau pathology,
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