Publications by authors named "Yang H Lee"

Purpose: Biological dosimetry is an essential analytic method to estimate the absorbed radiation dose in the human body by measuring changes in biomolecules after radiation exposure. Joint response in a network to mass-casualty radiation incidents is one way to overcome the limitations of biological dosimetry, sharing the workload among laboratories. This study aimed to investigate the current performance, collaborative activities and technical advances of the Korea biodosimetry network (K-BioDos), and suggest the future directions toward successful joint response.

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Purpose: Networking with other biodosimetry laboratories is necessary to assess the radiation exposure of many individuals in large-scale radiological accidents. The Korea biodosimetry network, K-BioDos, prepared harmonized scoring guidelines for dicentric chromosome assay to obtain homogeneous results within the network and investigated the efficiency of the guidelines.

Materials And Methods: Three laboratories in K-BioDos harmonized the scoring guidelines for dicentric chromosome assay.

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People exposed to radiation in cancer therapy and nuclear accidents are at increased risk of cardiovascular outcomes in long-term survivors. Extracellular vesicles (EVs) are involved in radiation-induced endothelial dysfunction, but their role in the early stage of vascular inflammation after radiation exposure remains to be fully understood. Herein, we demonstrate that endothelial cell-derived EVs containing miRNAs initiate monocyte activation in radiation-induced vascular inflammation.

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Article Synopsis
  • This study focused on the potential neuroprotective effects of dihydropyridines (DHPs) for patients with Parkinson's disease (PD), particularly examining how DHPs affect motor and cognitive functions over time.
  • Researchers analyzed 476 drug-naive PD patients and categorized them based on their hypertension status and DHP use, finding that DHP use is linked to a lower risk of developing dementia in hypertensive patients.
  • The study concluded that while dopamine transporter activity was similar across groups, those using DHPs showed better long-term cognitive outcomes, suggesting a beneficial role of DHPs in managing PD in patients with hypertension.
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The dicentric chromosome assay (DCA) is considered the gold standard for radiation biodosimetry, but it is limited by its long dicentric scoring time and need for skilled scorers. The automation of scoring dicentrics has been considered a strategy to overcome the constraints of DCA. However, the studies on automated scoring methods are limited compared to those on conventional manual DCA.

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Article Synopsis
  • Microhaplotypes (microhaps) are new genetic markers designed to enhance forensic identification, addressing the limitations of traditional methods like STRs and SNPs.
  • This study introduced a custom MPS panel that can simultaneously amplify 56 microhaps and includes a web-based tool called Visual Microhap for streamlined data analysis.
  • Analysis of these microhaps across 286 samples from diverse populations showed their effectiveness in human identification, revealing distinct group differences and suggesting improved forensic application compared to standard STRs.
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Spontaneous hemothorax is rare, with limited data available on its etiology and treatment. We report a case of massive spontaneous hemothorax with a ruptured variceal phrenic vein during pregnancy, likely a complication of the Kasai procedure. Despite closed thoracostomy, the patient's symptoms and imaging findings did not improve.

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Polyetheretherketone (PEEK) is the only polymer material that can replace titanium implants in the field of orthopedics. This is because the mechanical properties of PEEK are similar to those of bone, and PEEK has natural radiolucency, chemical stability, and sterilization resistance. Despite these advantages, PEEK has a disadvantage-that it is bio-inert.

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Although radiological accidents often result in partial-body radiation exposure, most biodosimetry studies focus on estimating whole-body exposure doses. We have evaluated time-dependent changes in chromosomal aberrations before, during, and after localized fractionated radiotherapy. Twelve patients with carcinoma in situ of the breast who underwent identical adjuvant radiation therapy (50 Gy in 25 fractions) were included in the study.

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Background: Although levodopa-induced dyskinesia-relevant white matter change has been evaluated, it is uncertain whether these changes may reflect the underlying predisposing conditions leading to the development of levodopa-induced dyskinesia.

Objective: To elucidate the role of white matter connectivity networks in the development of levodopa-induced dyskinesia in drug-naïve Parkinson's disease.

Methods: We recruited 30 patients who developed levodopa-induced dyskinesia within 5 years from MRI acquisition (vulnerable-group), 47 patients who had not developed levodopa-induced dyskinesia within 5 years (resistant-group), and 28 controls.

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Background: This study is aimed at investigating the safety and tolerability of the intra-arterial administration of autologous bone marrow-derived mesenchymal stem cells (BM-MSCs) in patients with multiple system atrophy- (MSA-) cerebellar type (MSA-C).

Methods: This was a single-center, open-label phase I clinical trial in patients with MSA-C. A three-stage dose escalation scheme (low-dose, 3.

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Background: Premorbid educational attainment is a well-known proxy of reserve, not only with regard to cognition, but also to motor symptoms.

Objective: In the present study, we investigated the relationship between educational attainment and long-term motor prognosis in patients with Parkinson's disease (PD).

Methods: We analyzed 466 patients with de novo PD without dementia who underwent dopamine transporter (DAT) scans and were followed up more than 2 years.

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The pons is one of the earliest affected regions in patients with synucleinopathies. We aimed to investigate the diagnostic value of measuring pontine damage using diffusion tensor imaging (DTI) in these patients. We enrolled 49 patients with Parkinson's disease (PD), 16 patients with idiopathic rapid eye movement sleep behavior disorder (iRBD), 23 patients with multiple system atrophy (MSA), and 39 healthy controls in this study.

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Statins are more widely used not only for the primary and secondary prevention of cardiovascular disease by blocking cholesterol biosynthesis but also for the potential neuroprotective agents during neurological disorders due to their pleiotropic effects. In this study, we investigate whether the previous use of statins affect baseline nigrostriatal dopamine loss at the time of diagnosis and longitudinal motor and cognitive outcomes in patients with Parkinson's disease. Five hundred drug-naïve patients with Parkinson's disease who underwent dopamine transporter imaging were classified into two groups according to the prior use of statins: patients with and without statin use.

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The role of apolipoprotein E4 (APOE4) in the risk of Alzheimer's disease (AD) and Lewy body disease (LBD), and their relationship with β-amyloid deposition and cognitive dysfunction, remain unclear. Using amyloid and dopamine transporter imaging, we enrolled 126 controls and 208 patients with typical AD (pure AD and Lewy body variant of AD), AD with dementia with Lewy bodies, or typical LBD (dementia with Lewy bodies with amyloid deposition and pure LBD). APOE4 was associated with an increased risk of all disease subtypes except pure LBD.

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Background: Neuropsychiatric symptoms (NPS) are the most common non-motor symptom in Parkinson's disease (PD).

Objective: To investigate the association between the burden of NPS and motor prognosis in patients with PD.

Methods: We enrolled 329 drug-naïve patients with PD, who was non-demented and followed-up≥2 years after their first visit to the clinic with baseline dopamine transporter (DAT) imaging and neuropsychiatric inventory (NPI) scores.

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Purpose: Mutual cooperation of biodosimetry laboratories is required for dose assessments of large numbers of people with potential radiation exposure, as in mass casualty accidents. We launched an intercomparison exercise to validate the performance of biodosimetry laboratories in South Korea.

Materials And Methods: Participating laboratories shared metaphase images from dicentric chromosome assays (DCAs) and fluorescence hybridization (FISH)-based translocation assays, which were evaluated based on their own scoring protocols.

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Objectives: To investigate the association between cognitive function at baseline and the progression of motor disability in Parkinson's disease (PD).

Methods: We consecutively enrolled 257 drug-naïve patients with early-stage PD (follow-up > 2 years) who underwent a detailed neuropsychological test at initial assessment. Factor analysis was conducted to yield four cognitive function factors and composite scores thereof: Factor 1 (visual memory/visuospatial), Factor 2 (verbal memory), Factor 3 (frontal/executive), and Factor 4 (attention/working memory/language).

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Dipeptidyl peptidase 4 (DPP4) inhibitors are widely used hypoglycaemic agents and improve glucose metabolism by enhancing the bioavailability of active glucagon-like peptide-1. In this study, we hypothesized that treatment with DPP4 inhibitors may have beneficial effects on nigrostriatal dopamine and longitudinal motor performance in diabetic patients with Parkinson's disease. We classified 697 drug naive patients with de novo Parkinson's disease who had undergone dopamine transporter imaging into three groups according to a prior diagnosis of diabetes and use of DPP4 inhibitors: diabetic patients with Parkinson's disease being treated with (n = 54) or without DPP4 inhibitors (n = 85), and non-diabetic patients with Parkinson's disease (n = 558).

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Objective: We evaluated disruption of the white matter (WM) network related with Alzheimer's disease (AD) and Lewy body disease (LBD), which includes Parkinson's disease and dementia with Lewy bodies.

Methods: We consecutively recruited 37 controls and 77 patients with AD-related cognitive impairment (ADCI) and/or LBD-related cognitive impairment (LBCI). Diagnoses of ADCI and LBCI were supported by amyloid PET and dopamine transporter PET, respectively.

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Background: To investigate the relationship between temporalis muscle thickness (TMT) at baseline as a surrogate marker for sarcopenia and long-term motor outcomes in patients with Parkinson's disease (PD).

Methods: We enrolled 249 patients with drug-naïve early-stage PD (119 males and 130 females, follow-up > 3 years). Baseline TMT of each patient was measured on the axial plane of T1-weighted images.

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Most blood components for transfusions are irradiated ex vivo to prevent transfusion-associated graft-versus-host disease (TA-GvHD); this irradiation can potentially affect the cytogenetic dose assessment of patients showing acute radiation syndrome (ARS) with bone marrow suppression or acute anaemia. Whole blood samples from five donors were irradiated with 0, 10 or 25 Gy γ-rays. The mitotic activity of each cultured blood sample was measured by calculating the mitotic index.

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We investigated the efficacy of donepezil for mild cognitive impairment in Parkinson's disease (PD-MCI). This was a prospective, non-randomized, open-label, two-arm study. Eighty PD-MCI patients were assigned to either a treatment or control group.

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Background: White matter hyperintensities, prevalent in patients with Parkinson's disease (PD), significantly affect parkinsonian motor symptoms. The objective of this study was to investigate the relationship between white matter hyperintensities and nigrostriatal dopamine depletion and their interaction or mediating effects on motor symptoms in patients with drug-naive early-stage PD.

Methods: This cross-sectional study enrolled 501 patients with de novo PD who initially underwent [ F] N-(3-fluoropropyl)-2β-carbonethoxy-3β-(4-iodophenyl) nortropane positron emission tomography and brain magnetic resonance imaging scans between April 2009 and September 2015 in a tertiary-care university hospital.

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