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Search Results: 1 - 10 of 10801 matches for " Yeo Seung-Gu "
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Up-regulated expression of l-caldesmon associated with malignancy of colorectal cancer
Kim Kyung-Hee,Yeo Seung-Gu,Kim Won Ki,Kim Dae Yong
BMC Cancer , 2012, DOI: 10.1186/1471-2407-12-601
Abstract: Background Caldesmon (CaD), a major actin-associated protein, is found in smooth muscle and non-muscle cells. Smooth muscle caldesmon, h-CaD, is a multifunctional protein, and non-muscle cell caldesmon, l-CaD, plays a role in cytoskeletal architecture and dynamics. h-CaD is thought to be an useful marker for smooth muscle tumors, but the role(s) of l-CaD has not been examined in tumors. Methods Primary colon cancer and liver metastasis tissues were obtained from colon cancer patients. Prior to chemoradiotherapy (CRT), normal and cancerous tissues were obtained from rectal cancer patients. Whole-tissue protein extracts were analyzed by 2-DE-based proteomics. Expression and phosphorylation level of main cellular signaling proteins were determined by western blot analysis. Cell proliferation after CaD siRNA transfection was monitored by MTT assay. Results The expression level of l-CaD was significantly increased in primary colon cancer and liver metastasis tissues compared to the level in the corresponding normal tissues. In cancerous tissues obtained from the patients showing poor response to CRT (Dworak grade 4), the expression of l-CaD was increased compared to that of good response group (Dworak grade 1). In line with, l-CaD positive human colon cancer cell lines were more resistant to 5-fluorouracil (5-FU) and radiation treatment compared to l-CaD negative cell lines. Artificial suppression of l-CaD increased susceptibility of colon cancer cells to 5-FU, and caused an increase of p21 and c-PARP, and a decrease of NF-kB and p-mTOR expression. Conclusion Up-regulated expression of l-CaD may have a role for increasing metastatic property and decreasing CRT susceptibility in colorectal cancer cells.
Whole-liver radiotherapy for end-stage colorectal cancer patients with massive liver metastases and advanced hepatic dysfunction
Seung-Gu Yeo, Dae Yong Kim, Tae Hyun Kim, Sun Young Kim, Yong Sang Hong, Kyung Hae Jung
Radiation Oncology , 2010, DOI: 10.1186/1748-717x-5-97
Abstract: Between June 2004 and July 2008, 10 colorectal cancer patients, who exhibited a replacement of over three quarters of their normal liver by metastatic tumors and were of Child-Pugh class B or C in liver function with progressive disease after undergoing chemotherapy, underwent whole-liver RT. RT was administered using computed tomography-based three-dimensional planning and the median dose was 21 Gy (range, 21-30) in seven fractions. Improvement in liver function tests, defined as a decrease in the levels within 1 month after RT, symptom palliation, toxicity, and overall survival were analyzed retrospectively.Levels of alkaline phosphatase, total bilirubin, aspartate transaminase, and alanine transaminase improved in 8, 6, 9, and all 10 patients, respectively, and the median reduction rates were 42%, 68%, 50%, and 57%, respectively. Serum carcinoembryonic antigen level decreased after RT in three of four assessable patients. For all patients, pain levels decreased and acute toxicity consisted of nausea/vomiting of grade ≤ 2. Further chemotherapy became possible in four of 10 patients. Mean survival after RT was 80 ± 80 days (range, 20-289); mean survival for four patients who received post-RT chemotherapy was 143 ± 100 days (range, 65-289), versus 38 ± 16 days (range, 20-64) for the six patients who did not receive post-RT chemotherapy (p = 0.127).Although limited by small case number, this study demonstrated a possible role of whole-liver RT in improving hepatic dysfunction and delaying mortality from hepatic failure for end-stage colorectal cancer patients with massive liver metastases. Further studies should be followed to confirm these findings.Most colorectal cancer deaths are attributable to distant metastases, frequently in the liver. At diagnosis, approximately 20% of colorectal cancer patients have liver metastases, and about half of patients initially diagnosed with localized disease develop metachronous liver metastases [1-3]. Curative resection of liver
Accelerated partial breast irradiation using multicatheter brachytherapy for select early-stage breast cancer: local control and toxicity
Seung-Gu Yeo, Juree Kim, Geum-Hee Kwak, Ji-Young Kim, Kyeongmee Park, Eun Seok Kim, Sehwan Han
Radiation Oncology , 2010, DOI: 10.1186/1748-717x-5-56
Abstract: Between 2002 and 2006, 48 prospectively selected patients with early-stage breast cancer received APBI using multicatheter brachytherapy following breast-conserving surgery. Their median age was 52 years (range 36-78). A median of 34 Gy (range 30-34) in 10 fractions given twice daily within 5 days was delivered to the tumor bed plus a 1-2 cm margin. Most (92%) patients received adjuvant systemic treatments. The median follow-up was 53 months (range 36-95). Actuarial local control rate was estimated from surgery using Kaplan-Meier method.Local recurrence occurred in two patients. Both were true recurrence/marginal miss and developed in patients with close (< 0.2 cm) surgical margin after 33 and 40 months. The 5-year actuarial local recurrence rate was 4.6%. No regional or distant relapse and death has occurred to date. Late Grade 1 or 2 late skin and subcutaneous toxicity was seen in 11 (22.9%) and 26 (54.2%) patients, respectively. The volumes receiving 100% and 150% of the prescribed dose were significantly higher in the patients with late subcutaneous toxicity (p = 0.018 and 0.034, respectively). Cosmesis was excellent to good in 89.6%.APBI using HDR multicatheter brachytherapy yielded local control, toxicity, and cosmesis comparable to those of conventional whole breast irradiation for select early-stage breast cancer. Patients with close resection margins may be ineligible for APBI.Over the last decades, breast-conserving surgery (BCS) followed by whole breast irradiation (WBI) became the standard of care for the treatment of early-stage breast cancer. However, the 5-6 weeks of conventional WBI are problematic for elderly patients, working women, and those who live a great distance from a radiotherapy facility [1]. In addition, controversies and logistical problems exist that are associated with integrating this prolonged course of WBI and systemic chemotherapy [2]. These make a barrier to the acceptance of breast conservation by patients or their physicians, an
Structural and electronic properties of uranium-encapsulated Au14 cage
Yang Gao,Xing Dai,Seung-gu Kang,Camilo Andres Jimenez Cruz,Minsi Xin,Yan Meng,Jie Han,Zhigang Wang,Ruhong Zhou
Physics , 2013,
Abstract: The structural properties of the uranium-encapsulated nano-cage U@Au14 are predicted using density functional theory. The presence of the uranium atom makes the Au14 structure more stable than the empty Au14-cage, with a triplet ground electronic state for U@Au14. Analysis of the electronic structure shows that the two frontier single-occupied molecular orbital electrons of U@Au14 mainly originate from the 5f shell of the U atom after charge transfer. Meanwhile, the bonding orbitals have both the 5f and 6d components of the U atom, along with the 5d and 6s components of the Au atoms, indicating the covalent nature of the interaction between the U and Au atoms. Moreover, the charge population analysis shows that this nanostructure displays some unique electronic properties where the encapsulated atom gains electrons while the outer shell loses electrons. Therefore, this designed U@Au14 nano-cage structure is stabilized by ionocovalent interactions. The current findings provide theoretical basis for future syntheses and further study of actinide doped gold nanoclusters, which might subsequently facilitate applications of such structure in radio-labeling, nanodrug carrier and other biomedical applications.
Selection of an HLA-C*03:04-Restricted HIV-1 p24 Gag Sequence Variant Is Associated with Viral Escape from KIR2DL3+ Natural Killer Cells: Data from an Observational Cohort in South Africa
Angelique H?lzemer?,Christina F. Thobakgale?,Camilo A. Jimenez Cruz?,Wilfredo F. Garcia-Beltran?,Jonathan M. Carlson?,Nienke H. van Teijlingen?,Jaclyn K. Mann?,Manjeetha Jaggernath?,Seung-gu Kang?,Christian K?rner
PLOS Medicine , 2015, DOI: 10.1371/journal.pmed.1001900
Abstract: Background Viruses can evade immune surveillance, but the underlying mechanisms are insufficiently understood. Here, we sought to understand the mechanisms by which natural killer (NK) cells recognize HIV-1-infected cells and how this virus can evade NK-cell-mediated immune pressure. Methods and Findings Two sequence mutations in p24 Gag associated with the presence of specific KIR/HLA combined genotypes were identified in HIV-1 clade C viruses from a large cohort of infected, untreated individuals in South Africa (n = 392), suggesting viral escape from KIR+ NK cells through sequence variations within HLA class I—presented epitopes. One sequence polymorphism at position 303 of p24 Gag (TGag303V), selected for in infected individuals with both KIR2DL3 and HLA-C*03:04, enabled significantly better binding of the inhibitory KIR2DL3 receptor to HLA-C*03:04-expressing cells presenting this variant epitope compared to the wild-type epitope (wild-type mean 18.01 ± 10.45 standard deviation [SD] and variant mean 44.67 ± 14.42 SD, p = 0.002). Furthermore, activation of primary KIR2DL3+ NK cells from healthy donors in response to HLA-C*03:04+ target cells presenting the variant epitope was significantly reduced in comparison to cells presenting the wild-type sequence (wild-type mean 0.78 ± 0.07 standard error of the mean [SEM] and variant mean 0.63 ± 0.07 SEM, p = 0.012). Structural modeling and surface plasmon resonance of KIR/peptide/HLA interactions in the context of the different viral sequence variants studied supported these results. Future studies will be needed to assess processing and antigen presentation of the investigated HIV-1 epitope in natural infection, and the consequences for viral control. Conclusions These data provide novel insights into how viruses can evade NK cell immunity through the selection of mutations in HLA-presented epitopes that enhance binding to inhibitory NK cell receptors. Better understanding of the mechanisms by which HIV-1 evades NK-cell-mediated immune pressure and the functional validation of a structural modeling approach will facilitate the development of novel targeted immune interventions to harness the antiviral activities of NK cells.
High-risk Human Papillomavirus Infection in Low Risk Women: Incidence, Patient Characteristics, and Clinical Meaning for Cervical Cancer
Sung Jong Lee, Seung Geun Yeo, Dong Choon Park
International Journal of Medical Sciences , 2012,
Abstract: Objective: To investigate the incidence of high-risk human papillomavirus (HPV) infection and its clinical meaning. Methods: Total 28,339 women attending our hospital for routine gynecologic care underwent Papanicolaou test (PAP test) and high-risk HPV tests. Biopsies were taken from some women and their results were compared. Results: The prevalence of high-risk HPV infection is 24.15%. And the women aged 20-29 years had the highest prevalence (32.3%) compared to 30-70 years (P<0.05). Of the 28,339 women, 1369 (4.83%) had positive PAP test (ASCUS, LSIL, HSIL). Of the 1369 PAP-positive patients, only 16 (1.17%) were negative for HPV test. Of the 1353 patients positive on both tests, 510 (37.7%) had lesions higher than CINII on histology. Of the 1,611 patients who underwent biopsies, 350 underwent the loop electrical excision procedure, with 339 (96%) being positive for HPV test, including 16 with CINI, 48 with CINII/III, 74 with CIS, and 16 with cervical cancer. HPV test had a positive predictive value of 40.7% and a negative predictive value of 100% for higher than CINII. Conclusion: Although HPV test has a burden of cost, considering its high negative predictive value, HPV test should be considered for more useful screening test.
Electrochemical Investigation of Anthraquinone-Based Chemodosimeter for Cu2+ Metal Ion
Yeo Woon Yoon,Jong Seung Kim,Tae Hyun Kim
Journal of Chemistry , 2013, DOI: 10.1155/2013/830981
Abstract: The electrochemical properties of an anthraquinone-containing Cu2+-promoted desulfurization chemodosimeter (AQCD) in the presence of various metal ions were investigated by voltammetry. AQCD showed voltammetric changes toward divalent metal ions (M2+), which are similar to those of anthraquinone (AQ) and 1-aminoanthraquinone (AQNH2) with the metal ions except Cu2+. This can be explained on the electrostatic interaction (AQCD-M2+) and chemodosimetric reaction (AQCD-Cu2+). 1. Introduction Chemodosimeters are used for sensing an analyte through a usually rapid response, highly selective, and irreversible chemical reaction between dosimeter molecule and the target material, leading to an observable signal [1–5]. Most have been utilized as optical sensors to monitor the target by UV/Vis and fluorescence spectroscopic measurements [1, 2]. These methods are usually sensitive, easy to perform, and inexpensive, but they have limitations in portability and mobility in terms of practical sensor devices. Alternatively, analytical techniques based on electrochemical detection are suitable for the development of convenient, sensitive, selective, and low cost tools that could be exploited for rapid monitoring, ultimately applicable to hand-held or autonomous operation. However, only a few examples of electrochemical sensors using chemodosimeters have been reported [6–11]. These studies utilized ferrocene [6, 7], iridium(III) complex [8, 9], and pyridine-4-thione [10] as redox units. Previously, we reported an anthraquinone-containing chemodosimeter (AQCD) responsible for Cu2+ ion-induced desulfurization to exhibit highly selective UV and fluorescence changes (Scheme 1) [12]. Scheme 1: Anthraquinone-based chemodosimeter (AQCD) and its reaction mechanism upon Cu 2+ ion addition. The anthraquinone unit can serve not only as a chromofluorescent unit but also as a redox center. It has largely proved to be an effective, remarkable and promising redox-signaling unit for electrochemical applications due to its robust electrochemistry [13–15]. Here, we report now the redox properties as well as cation sensing behavior of AQCD in the absence and the presence of alkali, alkaline earth, Cu2+, and other metal ions by voltammetry. The present study aims to investigate the electrochemical influence of various metal ions on AQCD behavior in terms of chemodosimetric reaction confirmed previously by optical methods [12] and consequently to check the feasibility of anthraquinone-based chemodosimeter as an electrochemical sensor for metal ions. In the pursuit of this goal,
Expression of CYLD and NF- B in Human Cholesteatoma Epithelium
Jae Yong Byun,Tae Young Yune,Jee Youn Lee,Seung Geun Yeo,Moon Suh Park
Mediators of Inflammation , 2010, DOI: 10.1155/2010/796315
Abstract: The tumor suppressor CYLD is a deubiquitinating enzyme that inhibits activation of the NF-B, which has key roles in inflammation and apoptosis. We hypothesized that CYLD may regulate the NF-B signaling pathway in cholesteatoma. We conducted immunohistochemistry to examine the expression of CYLD and NF-B in 16 cases of cholesteatoma and paired cases of retroauricular (RA) skin. In cholesteatoma epithelium, activated NF- B expression was significantly higher than in RA skin, whereas CYLD expression was significantly lower in cholesteatoma epithelium than in RA skin (<.05). Furthermore, a significant inverse correlation was detected between CYLD and activated NF-B expression in cholesteatoma epithelium (=?0.630). We found that CYLD reduced and activated increased NF-B in cholesteatoma epithelium in comparison to RA skin. The inverse correlation between CYLD and activated NF-B in cholesteatoma may be involved in cholesteatoma epithelial hyperplasia.
Effects of Female Sex Hormones on Clusterin Expression and Paclitaxel Resistance in Endometrial Cancer Cell Lines
Yong Sung Won, Sung Jong Lee, Seung Geun Yeo, Dong Choon Park
International Journal of Medical Sciences , 2012,
Abstract: Objective: We have analyzed the association between clusterin expression in endometrial cancer cells and their resistance to paclitaxel. We also analyzed whether the effects of female sex hormones on clusterin expression by these cell lines affect their resistance to paclitaxel. Methods: The expression of estrogen receptors α and β, progesterone receptors AB and B, and clusterin mRNA and protein was assayed in the ECC-1 and KLE endometrial cancer cell lines by RT-PCR and Western blotting, respectively. The IC50 of paclitaxel was measured in each cell line by XTT assay. Using clusterin siRNA, we analyzed the association between clusterin expression and paclitaxel IC50 in each cell line. We also examined the effects of hormone treatment on cellular resistance to paclitaxel. Results: Paclitaxel IC50 was significantly higher in KLE cells, which expressed higher levels of clusterin, than in ECC-1 cells, which expressed lower levels of clusterin. Conversely, incubation with clusterin siRNA significantly decreased the viability of KLE cells (P<0.001), but did not alter the viability of ECC-1 cells. Incubation with estrogen tended to increase the level of clusterin expression in these endometrial cancer cell lines, although the level of clusterin expression did not correlate with that of estrogen receptors. Incubation with progesterone did not alter the levels of expression of clusterin and clusterin receptor. Incubation with estrogen and paclitaxel significantly increased the viability of ECC-1 (P<0.001) but not KLE cells. Conclusion: Estrogen increases the paclitaxel resistance of endometrial cancer cell lines, by increasing clusterin expression.
Reconstruction of the Head and Neck Region Using Lower Trapezius Musculocutaneous Flaps
Soo Kwang Yoon,Seung Han Song,Nakheon Kang,Yeo-Hoon Yoon
Archives of Plastic Surgery , 2012, DOI: http://dx.doi.org/10.5999/aps.2012.39.6.626
Abstract: Background Recent literature has indicated that free flaps are currently considered thepreferred choice for head and neck reconstruction. However, head and neck cancer patients arefrequently treated with chemoradiotherapy, which is often associated with a poor general andlocal condition, and thus, such patients are ineligible for free flap reconstruction. Therefore,other reconstruction modalities should be considered.Methods We used lower trapezius musculocutaneous (LTMC) flap based on the dorsal scapularartery to reconstruct head and neck defects that arose from head and neck cancer in 8 patients.All of the patients had undergone preoperative chemoradiotherapy.Results There were no complications except one case of partial flap necrosis; it was treatedwith secondary intention. Healing in the remaining patients was uneventful without hematoma,seroma, or infection. The donor sites were closed primarily.Conclusions The LTMC flap is the preferred flap for a simple, reliable, large flap with a widearc of rotation and minor donor-site morbidity. The authors recommend this versatile islandflap as an alternative to microvascular free tissue transfer for the reconstruction of defects inthe head and neck region, for patients that have undergone preoperative chemoradiotherapy.
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