Publications by authors named "Chulwon Choi"

Neurodegenerative disorders, particularly Alzheimer's and Parkinson's diseases, continue to challenge modern medicine despite therapeutic advances. Orphan G-protein-coupled receptors (GPCRs) have emerged as promising targets in the central nervous system, offering new avenues for drug development. This review focuses on the structural biology of orphan GPCRs implicated in these disorders, providing a comprehensive analysis of their molecular architecture and functional mechanisms.

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Structural and mechanistic studies on human odorant receptors (ORs), key in olfactory signaling, are challenging because of their low surface expression in heterologous cells. The recent structure of OR51E2 bound to propionate provided molecular insight into odorant recognition, but the lack of an inactive OR structure limited understanding of the activation mechanism of ORs upon odorant binding. Here, we determined the cryo-electron microscopy structures of consensus OR52 (OR52), a representative of the OR52 family, in the ligand-free (apo) and octanoate-bound states.

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Background: A chemotherapy of rituximab, fludarabine and cyclophosphamide (R-FC) has been accepted as a promising frontline chemotherapy in selected patients with chronic lymphocytic leukemia (CLL). Although R-FC regimen is a relatively dose-dense regimen and neutropenia incidence is more than 50%, primary prophylactic pegfilgrastim was not fully recommended in the clinical field. Therefore, the study evaluated the prophylactic effectiveness of pegfilgrastim to reduce the incidence of febrile neutropenia associated with R-FC of patients with CLL.

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Neuropeptide Y (NPY) and its receptors are expressed in various human tissues including the brain where they regulate appetite and emotion. Upon NPY stimulation, the neuropeptide Y1 and Y2 receptors (YR and YR, respectively) activate G signaling, but their physiological responses to food intake are different. In addition, deletion of the two N-terminal amino acids of peptide YY (PYY(3-36)), the endogenous form found in circulation, can stimulate YR but not YR, suggesting that YR and YR may have distinct ligand-binding modes.

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Epstein-Barr virus-infected B cells are found at high frequency in peripheral T cell lymphoma. Herein, we report a case involving excessive EBV-positive B cells accompanying peripheral T cell lymphoma, not otherwise specified in the nasopharynx masquerading as nasopharyngeal extranodal NK/T cell lymphoma. A large number of Epstein-Barr virus-infected B cells infiltrate in between CD3-positive cytotoxic tumor T cells, as if EBV was infecting tumor T cells.

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Composite lymphoma is very rare and a combination of Hodgkin lymphoma and non-Hodgkin lymphoma and even histiocytic tumors can occur. Because of the unfamiliarity, not only can this cause diagnostic problems, but can also affect treatment plan. We report a case of composite lymphoma in a 40-year-old male.

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Objective: To report treatment outcomes of stereotactic ablative radiation therapy (SABR) for non-spinal bone metastases in a single institution, and to compare assessments of Response Evaluation Criteria in Solid Tumors (RECIST) v. 1.1 and the University of Texas MD Anderson Cancer Center (MDA) criteria.

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DegP, a member of the highly conserved HtrA family of proteases, performs a regulated proteolysis of toxic misfolded proteins in the periplasm of Gram-negative bacteria. The allosteric switch between inactive and active conformations is a central mechanism to carefully control proteolytic activity of DegP and to maintain the optimal cellular fitness, but few other molecules than substrates are known to allosterically control DegP activity. Here, we demonstrate that a mutant variant of an outer-membrane lipoprotein, Lpp, can function as a novel allosteric effector that changes the dynamic range of DegP activity.

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The Lin28/let-7 axis plays an important role in tumor initiation and developmental processes. Lin28B is upregulated in a variety of cancers, and its overexpression enhances cancer cell proliferation and radioresistance through the suppression of let-7 micro RNA expression. In this study, we investigated the role of the Lin28/let7 axis as a target for radiosensitization of melanoma cancer cells.

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Aim: To evaluate local control and patient survival for recurrent or oligometastatic uterine cervical cancer treated with stereotactic body radiotherapy (SBRT) using CyberKnife, and to demonstrate the safety of SBRT.

Patients And Methods: Between 2002 and 2013, 100 recurrent or oligometastatic lesions in 85 patients were treated with SBRT at three Institutions. SBRT sites were within the previous RT field in 59 and partially overlapped in nine.

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Purpose: We reviewed survival, local control, and toxicity in patients with locally recurrent nasopharyngeal carcinoma (NPC) who had been treated with fractionated stereotactic radiotherapy (FSRT).

Materials And Methods: Between June 2002 and March 2008, we retrospectively reviewed 35 patients with locally recurrent NPC treated using FSRT with CyberKnife. Gross tumor volumes ranged from 2.

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Purpose: To investigate the clinical application of a stereotactic body radiation therapy (SBRT) boost in locally advanced pancreatic cancer patients with a focus on local efficacy and toxicity.

Methods And Materials: We retrospectively reviewed 30 patients with locally advanced and nonmetastatic pancreatic cancer who had been treated between 2004 and 2006. Follow-up duration ranged from 4 to 41 months (median, 14.

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Objective: To investigate the clinical applications of stereotactic body radiation therapy (SBRT) using the CyberKnife system for pelvic recurrence from rectal cancer with a focus on survival and toxicity.

Methods: Between 2002 and 2006, 23 patients with recurrent rectal cancer were treated with SBRT at our institution. The median follow-up was 31 months.

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A 39-year-old woman presented with acute onset of arthralgia in both wrists. Although her primary gastric cancer was in remission after previous treatment, carcinomatous arthritis was suggested by the osteolytic radiographic findings and refractoriness to nonsteroidal anti-inflammatory drugs, which was then confirmed by synovial fluid cytopathology. In view of the high incidence of gastric cancer in Korea, gastric cancer involving the carpal bones should be considered when we encounter a patient presenting with inflammatory peripheral joint arthritis, which might be the first sign of recurrence.

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Background: Advanced biliary tract carcinoma is among the most prevalent fatal diseases in Korea. However, to our knowledge, to date no effective therapeutic modality has been shown to prolong the survival of patients in the inoperable stages of this disease.

Methods: This Phase II study was conducted to determine the efficacy and toxicity of a combined regimen of epirubicin, cisplatin, and uracil/tegafur (UFT) modulated by leucovorin in patients with advanced or recurrent biliary tract carcinoma.

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