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Search Results: 1 - 10 of 10048 matches for " Jung Kyu Choi "
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In Vitro Maturation of Cumulus-Oocyte Complexes for Efficient Isolation of Oocytes from Outbred Deer Mice
Jung Kyu Choi, Xiaoming He
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0056158
Abstract: Background The outbred (as with humans) deer mice have been a useful animal model of research on human behavior and biology including that of the reproductive system. One of the major challenges in using this species is that the yield of oocyte isolation via superovulation is dismal according to the literature to date less than ~5 oocytes per animal can be obtained so far. Objective The goal of this study is to improve the yield of oocyte isolation from outbred deer mice close to that of most laboratory mice by in vitro maturation (IVM) of cumulus-oocyte complexes (COCs). Methods Oocytes were isolated by both superovulation and IVM. For the latter, COCs were obtained by follicular puncture of antral follicles in both the surface and inner cortical layers of ovaries. Immature oocytes in the COCs were then cultured in vitro under optimized conditions to obtain metaphase II (MII) oocytes. Quality of the oocytes from IVM and superovulation was tested by in vitro fertilization (IVF) and embryo development. Results Less than ~5 oocytes per animal could be isolated by superovulation only. However, we successfully obtained 20.3±2.9 oocytes per animal by IVM (16.0±2.5) and superovulation (4.3±1.3) in this study. Moreover, IVF and embryo development studies suggest that IVM oocytes have even better quality than that from superovulation The latter never developed to beyond 2-cell stage as usual while 9% of the former developed to 4-cells. Significance We have successfully established the protocol for isolating oocytes from deer mice with high yield by IVM. Moreover, this is the first ever success to develop in vitro fertilized deer mice oocytes beyond the 2-cell stage in vitro. Therefore, this study is of significance to the use of deer mice for reproductive biology research.
Effective interactions of axion supermultiplet and thermal production of axino dark matter
Kyu Jung Bae,Kiwoon Choi,Sang Hui Im
Physics , 2011, DOI: 10.1007/JHEP08(2011)065
Abstract: We discuss the effective interactions of axion supermultiplet, which might be important for analyzing the cosmological aspect of supersymmetric axion model. Related to axino cosmology, it is stressed that three seemingly similar but basically different quantities, the Wilsonian axino-gluino-gluon coupling, the 1PI axino-gluino-gluon amplitude, and the PQ anomaly coefficient, should be carefully distinguished from each other for correct analysis of the thermal production of axinos in the early Universe. It is then noticed that the 1PI axino-gluino-gluon amplitude at energy scale p in the range M_\Phi < p < v_{PQ} is suppressed by (M_\Phi ^2)/(p^2) in addition to the well-known suppression by p/(16\pi^2 v_{PQ}), where M_\Phi is the mass of the heaviest PQ-charged and gauge-charged matter supermultiplet in the model, which can be well below the PQ scale v_{PQ}. As a result, axino production at temperature T>M_\Phi is dominated by the production by matter supermultiplet, not by the production by gauge supermultiplet. Still the axino production rate is greatly reduced if M_\Phi << v_{PQ}, which would make the subsequent cosmology significantly altered. This would be most notable in the supersymmetric DFSZ model in which M_\Phi corresponds to the Higgsino mass which is around the weak scale, however a similar reduction is possible in the KSVZ model also. We evaluate the relic axino density for both the DFSZ and KSVZ models while including the axino production in the processes involving the heaviest PQ-charged and gauge-charged matter supermultiplet.
The effectiveness of ultrasonography in verifying the placement of a nasogastric tube in patients with low consciousness at an emergency center
Hyung Min Kim, Byung Hak So, Won Jung Jeong, Se Min Choi, Kyu Nam Park
Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine , 2012, DOI: 10.1186/1757-7241-20-38
Abstract: The study included 47 patients who were all over 18?years of age. In all patients, tube placement was verified by chest X-rays. Auscultation, pH analysis of gastric aspirates, and ultrasonography were conducted on each patient in random order. The mean patient age was 57.62?±?17.24?years, and 28 males (59.6%) and 19 females (40.4%) were included. The NGT was inserted by an emergency room resident. For pH testing, gastric aspirates were dropped onto litmus paper, and the resulting color of the paper was compared with a reference table. Ultrasonography was performed by an emergency medicine specialist, and the chest X-ray examination was interpreted by a different emergency medicine specialist who did not conduct the ultrasonography test. The results of the auscultation, gastric aspirate pH, and ultrasonography examinations were compared with the results of the chest x-ray examination.The sensitivity and specificity were 100% and 33.3%, respectively, for auscultation and 86.4% and 66.7%, respectively, for ultrasonography. Kappa values were the highest for auscultation at 0.484 compared to chest x-rays, followed by 0.299 for ultrasonography and 0.444 for pH analysis of the gastric aspirate. The ultrasonography has a positive predictive value of 97.4% and a negative predictive value of 25%.Ultrasonography is useful for confirming the results of auscultation after NGT insertion among patients with low consciousness at an emergency center. When ultrasound findings suggest that the NGT placement is not gastric, additional chest X-ray should be performed.
Long-term effect of stereotactic body radiation therapy for primary hepatocellular carcinoma ineligible for local ablation therapy or surgical resection. Stereotactic radiotherapy for liver cancer
Jung Kwon, Si Bae, Ji Kim, Byung Choi, Hong Jang, Jeong Jang, Jong Choi, Seung Yoon, Kyu Chung
BMC Cancer , 2010, DOI: 10.1186/1471-2407-10-475
Abstract: Forty-two HCC patients with tumors ≤ 100 cc and ineligible for local ablation therapy or surgical resection were treated with SBRT: 30-39 Gy with a prescription isodose range of 70-85% (median 80%) was delivered daily in three fractions. Median tumor volume was 15.4 cc (3.0-81.8) and median follow-up duration 28.7 months (8.4-49.1).Complete response (CR) for the in-field lesion was initially achieved in 59.6% and partial response (PR) in 26.2% of patients. Hepatic out-of-field progression occurred in 18 patients (42.9%) and distant metastasis developed in 12 (28.6%) patients. Overall in-field CR and overall CR were achieved in 59.6% and 33.3%, respectively. Overall 1-year and 3-year survival rates were 92.9% and 58.6%, respectively. In-field progression-free survival at 1 and 3 years was 72.0% and 67.5%, respectively. Patients with smaller tumor had better in-field progression-free survival and overall survival rates (<32 cc vs. ≥32 cc, P < 0.05). No major toxicity was encountered but one patient died with extrahepatic metastasis and radiation-induced hepatic failure.SBRT is a promising noninvasive-treatment for small HCC that is ineligible for local treatment or surgical resection.Hepatocellular carcinoma (HCC) is one of the most common malignant diseases [1-3]. Of the current therapeutic approaches for HCC, surgical resection and liver transplantation are used with curative intent for patients with small HCC [4]. However, the majority of HCC patients are ineligible for surgery because most have a cirrhotic liver with poor liver function or tumors are located in the central segments. Several modalities including radiofrequency ablation (RFA) and percutaneous ethanol injection (PEI) have been used to treat small HCC, but the optimal treatment remains controversial particularly for cases of small HCC ineligible for curative therapy.Cyberknife (Accuracy Inc., Sunnyvale, CA) is a new stereotactic body radiation therapy (SBRT) that delivers a high dose of radiation in a
Two Distinct Functional Patterns of Hepatitis C Virus (HCV)-Specific T Cell Responses in Seronegative, Aviremic Patients
Yoon Seok Choi, Jung Eun Lee, Seung Joo Nam, Jung Tak Park, Hyon-Suk Kim, Kyu Hun Choi, Beom Seok Kim, Eui-Cheol Shin
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0062319
Abstract: In hepatitis C Virus (HCV) high-risk groups, HCV-specific T cell responses have been detected in seronegative, aviremic persons who have no evidence of HCV infection. Herein, we investigated functional profiles of HCV-specific T-cell responses in seronegative, aviremic patients of a HCV high-risk group. Seventy seven hemodialysis patients with chronic renal disease were analyzed by IFN-γ ELISpot assays, and eight of 71 (11.3%) seronegative, aviremic patients displayed HCV-specific T-cell responses. Their HCV-specific memory T cells were characterized by assessing cytokine polyfunctionality, known to provide antiviral protection. By intracellular staining of IFN-γ, TNF-α, IL-2 and MIP-1β, we identified two distinct populations in the seronegative, aviremic patients: polyfunctional responders and TNF-α-predominant responders. In further analysis, occult HCV infection was excluded as a cause of the HCV-specific T cell response via secondary nested RT-PCR of HCV RNA in peripheral blood mononuclear cell samples. HCV-specific T cells targeted multiple epitopes including non-structural proteins in a single patient, implying that their T cells might have been primed by HCV proteins synthesized within the host. We conclude that HCV-specific memory T cells of seronegative, aviremic patients arise from authentic HCV replication in the host, but not from current occult HCV infection. By functional pattern of HCV-specific T cells, there are two distinct populations in these patients: polyfunctional responders and TNF-α-predominant responders.
Induction of Interleukin-8 from Nasal Epithelial Cells during Bacterial Infection: The Role of IL-8 for Neutrophil Recruitment in Chronic Rhinosinusitis
Bit-Na Yoon,Nan-Geum Choi,Hyun-Sun Lee,Kyu-Sup Cho,Hwan-Jung Roh
Mediators of Inflammation , 2010, DOI: 10.1155/2010/813610
Abstract: Objectives. The aim of this study was to elucidate the role of IL-8 for neutrophil recruitment in nonallergic CRS patients. Methods. After coculture of Streptococcus pneumoniae (SP) with the mucosal epithelial cells (MECs) from non-CRS patients, at three different SP/MEC (1/1, 10/1, 100/1) ratios, the expression of IL-8 mRNA and the concentration of IL-8 were measured by RT-PCR and ELISA. The expression of CD11b/CD18 on neutrophils and E-selectin/ICAM-1 on endothelial cells and the adherence between neutrophils and human umbilical vascular endothelial cells (HUVECs) were determined by flow cytometric analysis, ELISA, and RIA, respectively. Results. IL-8 concentration and IL-8 mRNA expression continued to increase from 3 hours after incubation in SP number-dependent manner. The expression of CD11b/CD18 on neutrophils and E-selectin/ICAM-1 on HUVECs, and the adherence between neutrophils and HUVECs were significantly increased in 10 SP/MEC-CM, and the increments were significantly blocked by anti-IL-8 antibody. Conclusion. MEC and IL-8 are major factors for neutrophil recruitment in nonallergic CRS. 1. Introduction Histopathologically, nonallergic chronic rhinosinusitis (CRS) is characterized by neutrophil infiltration into sinus mucosa and most of the cells in the sinus effusion and nasal discharge are neutrophils [1]. The neutrophils are known as not only terminal effector cells for tissue destruction and antibacterial defense but also as immunocompetent cells that play an active role in the up-regulation of the inflammatory response by secreting a variety of cytokines such as IL-1 , IL-1 , IL-6, interferon- , TNF, and IL-8 [2]. Interleukin-8 (IL-8) is an inflammatory cytokine that participates in the pathogenesis of several neutrophil-infiltrating chronic inflammatory diseases such as bronchiectasis, diffuse panbronchiolitis, and cystic fibrosis [3]. It can be secreted by any cell with toll-like receptors such as nasal epithelial cells, nasal gland duct cells, and recruited neutrophils [4]. Previous studies have shown that IL-8 and neutrophils are highly detected in the nasal discharge and sinus mucosa of CRS patients, and they have positive feedback interactions with each other [3, 5]. The recruitment of neutrophils from the circulation into the extravascular space involves several steps. Recent advances in sinusitis research have revealed two positive feedback mechanisms that explain chronic neutrophil accumulation in the sinus effusion [3]. One is the transendothelial migration of neutrophils to the inflammatory sinus mucosa. The other is the
A Novel Multiplex Real-Time PCR Assay for the Concurrent Detection of Hepatitis A, B and C Viruses in Patients with Acute Hepatitis
Yongjung Park, Beom Seok Kim, Kyu Hun Choi, Dong Ho Shin, Mi Jung Lee, Yonggeun Cho, Hyon-Suk Kim
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0049106
Abstract: A novel multiplex real-time PCR assay for concurrent detection of hepatitis viruses was evaluated for its clinical performance in screening patients with acute hepatitis. A total of 648 serum samples were collected from patients with acute symptoms of hepatitis. Concurrent detection of nucleic acids of HAV, HBV and HCV was performed using the Magicplex? HepaTrio Real-time Detection test. Serum nucleic acid levels of HBV and HCV were also quantified by the Cobas? AmpliPrep/Cobas? TaqMan? (CAP/CTM) HBV and HCV tests. Patients’ medical records were also reviewed. Concordance rates between the results from the HepaTrio and the CAP/CTM tests for the detection of HBV and HCV were 94.9% (k = 0.88) and 99.2% (k = 0.98), respectively. The cycle threshold values with the HepaTrio test were also correlated well with the levels of HBV DNA (r = ?0.9230) and HCV RNA (r = ?0.8458). The sensitivity and specificity of the HepaTrio test were 93.8% and 98.2%, respectively, for detecting HBV infection, and 99.1% and 100.0%, respectively, for HCV infection. For the HepaTrio test, 21 (3.2%) cases were positive for both HBV and HCV. Among the positive cases, 6 (0.9%) were true coinfections. This test also detected 18 (2.8%) HAV positives. The HepaTrio test demonstrated good clinical performance and produced results that agreed well with those of the CAP/CTM assays, especially for the detection of HCV. This assay was also able to detect HAV RNA from anti-HAV IgM-positive individuals. Therefore, this new multiplex PCR assay could be useful for the concurrent detection of the three hepatitis viruses.
3,3′-Diethylthiatricarbocyanine Iodide: A Highly Sensitive Chiroptical Reporter of DNA Helicity and Sequence
Jung Kyu Choi,Alessandro D’Urso,Mitch Trauernicht,Murtaza Shabbir-Hussain,Andrea E. Holmes,Milan Balaz
International Journal of Molecular Sciences , 2011, DOI: 10.3390/ijms12118052
Abstract: Using UV-vis absorption and circular dichroism (CD) spectroscopies, we explored the binding interactions of 3,3′-diethylthiatricarbocyanine iodide ( Cy7) with polynucleotides of different sequences and helicity. CD showed to be a very diagnostic tool giving different spectroscopic chiroptical signatures for all explored DNA sequences upon Cy7 binding. Cy7 was able to spectroscopically discriminate between the right handed B-DNA of poly(dG-dC) 2 and its left handed Z-DNA counterpart induced by spermine or Co(III)hexamine via nearly opposite induced circular dichroic signal.
Reevaluating of the feasibility of ground-based earth-mass microlensing planet detections
Youn Kil Jung,Hyuk Park,Cheongho Han,Kyu-Ha Hwang,In-Gu Shin,Joon-Young Choi
Physics , 2014, DOI: 10.1088/0004-637X/786/2/85
Abstract: One important strength of the microlensing method in detecting extrasolar planets is its high sensitivity to low-mass planets. However, it is often believed that microlensing detections of Earth-mass planets from ground-based observation would be difficult due to the limit set by finite-source effects. This view comes from the previous estimation of the planet detection probability based on the fractional deviation of planetary signals, but proper probability estimation requires to additionally consider the source brightness, which is directly related to the photometric precision. In this paper, we reevaluate the feasibility of low-mass planet detections considering photometric precision for different populations of source stars. From this, it is found that contribution of the improved photometric precision to the planetary signal of a giant-source event is big enough to compensate the decrease of the magnification excess caused by finite-source effects. As a result, we find that giant-source events are suitable targets for Earth-mass planet detections with significantly higher detection probability than events involved with source stars of smaller radii and predict that Earth-mass planets would be detected by prospective high-cadence surveys.
Restoration of an Inner-City Stream and Its Impact on Air Temperature and Humidity Based on Long-Term Monitoring Data

Kyu Rang KIM,Tae Heon KWON,Yeon-Hee KIM,Hae-Jung KOO,Byoung-Cheol CHOI,Chee-Young CHOI,

大气科学进展 , 2009,
Abstract: Spatiotemporal changes in air temperature and humidity associated with the restoration of an inner-city stream in Seoul, Korea, are investigated based on long-term monitoring data. The Cheonggye stream, covered under a concrete structure for 46 years, was restored in 2005 and runs 5.8 km eastward through a central region of Seoul. Long-term monitoring of the air temperature and relative humidity was made along the stream throughout the restoration and across the stream after the restoration. The area along the stream had a higher air temperature than the entire metropolitan area. The temperature anomaly between the monitoring area and the surrounding metropolitan area was 0.13oC lower on average at the center of the stream after the restoration. The stream's effect on the air temperature was also evident in the temperature distribution along a street traversing the stream. The relative and specific humidities were increased due to the restoration. The restored stream modified the nearby urban climate in the opposite direction compared to urbanization. The results could be used as a model case in mitigating urban climate by a stream in future urban planning practices.
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