Publications by authors named "Sun Yong Baek"

Visualizing gradual changes in neuromelanin distribution within the substantia nigra is an important metric used to monitor the progression of Parkinsonism. This study aimed to identify the origin of the mismatch region between magnetic resonance transverse relaxation times (T and T*) in the substantia nigra and investigate its feasibility and implications for in vivo detection of neuromelanin as a clinical biomarker. The relationships between neuromelanin distribution assessed by histological staining and the area of T and T* mismatch determined by high- and low-resolution magnetic resonance relaxometry at 7T were directly compared in two normal and one depigmented substantia nigra collected at postmortem.

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Background: Providing feedback on student performance in the clinical performance assessment (CPA) is meaningful in that it helps students understand their strengths and weaknesses. This study compared students' perception of their CPA scores before and after providing personalized video feedback.

Methods: Two identical online surveys of Year 1 medical students (N = 103) that had undergone CPA were conducted to evaluate students' perceptions about their CPA scores before and after video feedback.

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Background: Task-specific checklists, holistic rubrics, and analytic rubrics are often used for performance assessments. We examined what factors evaluators consider important in holistic scoring of clinical performance assessment, and compared the usefulness of applying holistic and analytic rubrics respectively, and analytic rubrics in addition to task-specific checklists based on traditional standards.

Methods: We compared the usefulness of a holistic rubric versus an analytic rubric in effectively measuring the clinical skill performances of 126 third-year medical students who participated in a clinical performance assessment conducted by Pusan National University School of Medicine.

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Lymphoma is a heterogeneous disease with a highly variable clinical course and prognosis. Improving the prognosis for patients with relapsed and treatment-resistant lymphoma remains challenging. Current drug testing models based on 2D cell culture lack natural tissue-like structural organization and result in disappointing clinical outcomes.

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Neuromelanin (NM) is an endogenous iron chelating molecule of pigmented neurons in the human substantia nigra (SN). Along with the increase in iron deposition, the reduction in NM-containing dopaminergic neurons and the variation of iron load on NM are generally considered to be important factors participating to pathogenesis of Parkinson's disease (PD). The aim of this study was to non-invasively delineate the spatial distributions of paramagnetic magnetic susceptibility perturbers, such as NM-iron complex and ferric iron in SN.

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It has been proposed that susceptibility-weighted imaging is a sensitive magnetic resonance imaging (MRI) technique for identifying white matter (WM) pathologic changes involving demyelination and iron accumulation. We identified the tree silhouette-like configuration with a paramagnetic phase shift in the frontal subcortical WM lesions of 4 patients with adult-onset leukoencephalopathy with axonal spheroids and pigmented glia who underwent 3T MRI. According to our postmortem 7T MRI and histologic correlation study to investigate the origin of the susceptibility-related phase contrast, changes in the subcortical WM architecture and central WM loss with the relative preservation of iron-rich U-fibers may contribute to the paramagnetic susceptibility.

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Skin diseases associated with inflammation or oxidative stress represent the most common problem in dermatology. The present study demonstrates that fish scale collagen peptides (FSCP) protect against CoCl-induced cytotoxicity and TNF--induced inflammatory responses in human HaCaT keratinocyte cells. Our study is the first to report that FSCP increase cell viability and ameliorate oxidative injury in HaCaT cells through mechanisms mediated by the downregulation of key proinflammatory cytokines, namely, TNF-, IL-1, IL-8, and iNOS.

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IL-7 signaling via IL-7R and common -chain (c) is necessary for the development and homeostasis of T cells. Although the delicate mechanism in which IL-7R downregulation allows the homeostasis of T cell with limited IL-7 has been well known, the exact mechanism behind the interaction between IL-7R and c in the absence or presence of IL-7 remains unclear. Additionally, we are still uncertain as to how only IL-7R is separately downregulated by the binding of IL-7 from the IL-7R/c complex.

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High field magnetic resonance imaging (MRI)-based delineation of the substantia nigra (SN) and visualization of its inner cellular organization are promising methods for the evaluation of morphological changes associated with neurodegenerative diseases; however, corresponding MR contrasts must be matched and validated with quantitative histological information. Slices from two postmortem SN samples were imaged with a 7 Tesla (7T) MRI with T1 and T2* imaging protocols and then stained with Perl's Prussian blue, Kluver-Barrera, tyrosine hydroxylase, and calbindin immunohistochemistry in a serial manner. The association between T2* values and quantitative histology was investigated with a co-registration method that accounts for histology slice preparation.

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Objective: to investigate the effectiveness of the Micro Expression Training Tool (METT) and the Subtle Expression Training Tool (SETT) to help improve the non-verbal communication skills of medical students.

Methods: In a randomized controlled trial, all participants were randomly allocated to either a training (n=41) or control group (n=41) and were pre-tested before education with METT and SETT at baseline. Then, training students took second tests after a 1-h class about interpreting micro and subtle expressions and control students took the second tests without the class.

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Thymic epithelial cells (TECs) play a critical role in T-cell development through their intercellular interactions and by producing various soluble proteins, such as growth factors, cytokines and chemokines. In this study, we report a new role for epidermal growth factor-like domain 8 (EGFL8) in the regulation of the survival and proliferation of mouse thymocytes. Mouse recombinant EGFL8 (rEGFL8) protein was produced using an E.

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Increasing evidence indicates the potentially crucial roles of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in the pathological process underlying endometriosis. The present study aimed to investigate the effects of a hexane extract of aged black garlic (HEABG) on the proliferation and expression of ICAM-1 and VCAM-1 in tumor necrosis factor-α (TNF-α)-activated human endometrial stromal cells (HESCs) isolated from patients with endometriosis. HESCs were isolated from endometriotic tissues obtained from women with advanced endometriosis who underwent laparoscopic surgery for ovarian endometrioma (n=18).

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Unlike epidermal growth factor-like protein 7 (EGFL7), which is a secreted protein implicated in the regulation of blood vessel formation and cell migration, little is known about the physiological function of EGFL8. Thymic epithelial cells (TECs) play a pivotal role in T-cell development by regulating cellular interactions and expression of growth factors, cytokines, and chemokines. In order to investigate the functional role of EGFL8 in TECs, we transfected TECs with an EGFL8-expressing vector to overexpress EGFL8 protein and with an EGFL8 siRNA to knockdown EGFL8 expression.

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Background: Lamina-associated polypeptides 2 (LAP2) is a nuclear protein that connects the nuclear lamina with chromatin. Although its critical roles in genetic disorders and hematopoietic malignancies have been described, its expression and roles in digestive tract cancers have been poorly characterized.

Methods: To examine the expression of LAP2 in patient tissues, we performed immunohistochemistry and real-time PCR.

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Objective: Capsaicin, a noxious stimulant and main component of the hot flavor of red peppers, has an analgesic effect when administered to humans. We investigated the expression of proopioimelanocortin (POMC) mRNA in the arcuate nucleus of Sprague-Dawley (SD) rats after administering capsaicin, hypothesizing that administering capsaicin activates the central opioid system.

Methods: SD rats were divided randomly into two groups; one group received a saline injection and the other received a capsaicin injection.

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Background: Questioning is one of the essential techniques used by lecturers to make lectures more interactive and effective. This study surveyed the perception of questioning techniques by medical school faculty members and analyzed how the questioning technique is used in actual classes.

Methods: Data on the perceptions of the questioning skills used during lectures was collected using a self-questionnaire for faculty members (N = 33) during the second semester of 2008.

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Nuclear protein-1 (NUPR1) is a small nuclear protein that is responsive to various stress stimuli. Although NUPR1 has been associated with cancer development, its expression and roles in cholangiocarcinoma have not yet been described. In the present study, we found that NUPR1 was over-expressed in human cholangiocarcinoma tissues, using immunohistochemistry.

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Article Synopsis
  • * The study found that vitamin D3 significantly reduced the viability of gastric cancer and cholangiocarcinoma cells and worked well in combination with other anti-cancer drugs like paclitaxel and adriamycin.
  • * Vitamin D3 treatment decreased the expression of certain genes linked to cancer progression, indicating it may regulate cell growth through the hedgehog signaling pathway, suggesting a potential therapeutic role for vitamin D3 in these types of cancers.
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The thymus is a central lymphoid organ for T cell development. Thymic epithelial cells (TECs) constitute a major component of the thymic stroma, which provides a specialized microenvironment for survival, proliferation, and differentiation of immature T cells. In this study, subsets of TECs were examined immunohistochemically to investigate their cytokeratin (CK) expression patterns during thymus regeneration following thymic involution induced by cyclophosphamide treatment.

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Cancer stem cells have been hypothesized to drive the growth and metastasis of tumors. Because they need to be targeted for cancer treatment, they have been isolated from many solid cancers. However, cancer stem cells from primary human gastric cancer tissues have not been isolated as yet.

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Glioblastoma is the most common type of astrocytoma in the brain. Due to its high invasiveness and chemoresistance, patients with advanced stage of glioblastoma have a poor prognosis. SNAI1, an important regulator of epithelial-mesenchymal transition, has been associated with metastasis in various carcinoma cells.

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Intrahepatic cholangiocarcinoma is the second most common subtype of primary hepatobilliary cancer. Despite advances in surgical and medical therapy, its survival rate remains poor. Compared to hepatocellular carcinoma (HCC), the most common liver malignancy, the underlying mechanisms of cholangiocarcinoma carcinogenesis are poorly characterized.

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Purpose: Problem-based learning (PBL) is an educational approach in which complex authentic problems serve as the context and stimulus for learning. PBL is designed to encourage active participation during learning. The goal of this study was to study the effects of PBL on academic motivation and self-directed learning readiness in medical school students.

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Hedgehog (Hh) signaling is an essential pathway in embryonic development of prostate. Hh also plays roles in the proliferation of progenitor cells and cancer cells of adult prostate. However, how Hh signaling contributes to carcinogenesis of prostate is poorly understood.

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Gastric cancer is the second most common cause of cancer deaths worldwide. The underlying molecular mechanisms of its carcinogenesis are relatively poorly characterized. Hedgehog (Hh) signaling, which is critical for development of various organs including the gastrointestinal tract, has been associated with gastric cancer.

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