Publications by authors named "Chi-ming Chan"

Background: Meibomian gland dysfunction (MGD) is a primary cause of evaporative dry eye disease (DED), which is often exacerbated by cataract surgery due to surgical trauma and inflammation. Thermal pulsation therapy (TPT) aims to enhance meibomian gland function and relieve dry eye symptoms. We conducted a systematic review and meta-analysis to evaluate the effectiveness of TPT in managing dry eye symptoms associated with cataract surgery.

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Diabetic retinopathy is the most common retinal vascular disease, affecting the retina's blood vessels and causing chronic inflammation, oxidative stress, and, ultimately, vision loss. Diabetes-induced elevated glucose levels increase glycolysis, the main methylglyoxal (MGO) formation pathway. MGO is a highly reactive dicarbonyl and the most rapid glycation compound to form endogenous advanced glycation end products (AGEs).

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Article Synopsis
  • This study explores the link between retinal vein occlusion (RVO) and acute myocardial infarction (MI), highlighting how both conditions share similar risk factors like hypertension and diabetes, particularly in younger populations.
  • A comprehensive systematic review and meta-analysis of 12 studies involving over 371,000 participants indicated that RVO is associated with a 32.4% increased risk of MI, with central retinal vein occlusion (CRVO) showing a stronger association (69.1% increased risk) compared to branch retinal vein occlusion (BRVO).
  • The findings suggest that understanding the relationship between RVO and MI could help improve preventive measures and management strategies for at-risk individuals, despite some publication bias in the analyzed studies.
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  • Eye discomfort is a significant issue for patients after refractive eye surgeries, and a systematic review evaluated the pain relief effectiveness of pregabalin and gabapentin for this purpose.
  • Six studies involving 391 patients highlighted that pregabalin was more effective than a placebo on the first two postoperative days, while gabapentin had notable effectiveness by the second day only.
  • Both medications were found to safely reduce pain without increasing adverse events, suggesting the need for more research for improved long-term pain management strategies in ophthalmic care.
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The activation of microglia and the production of cytokines are key factors contributing to progressive neurodegeneration. Despite the well-recognized neuronal programmed cell death regulated by microglial activation, the death of microglia themselves is less investigated. Nucleotide-binding oligomerization domain, leucine-rich repeat-containing X1 (NLRX1) functions as a scaffolding protein and is involved in various central nervous system diseases.

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Calcium/calmodulin-dependent serine protein kinase (CASK) is a scaffold protein and plays critical roles in neuronal synaptic formation and brain development. Previously, CASK was shown to associate with EGFR to maintain the vulval cell differentiation in . In this study, we explored the role of CASK in CHME3 microglial cells.

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Background: Although stimulating autophagy caused by UV has been widely demonstrated in skin cells to exert cell protection, it remains unknown the cellular events in UVA-treated retinal pigment epithelial (RPE) cells.

Methods: Human ARPE-19 cells were used to measure cell viability, mitochondrial reactive oxygen species (ROS), mitochondrial membrane potential (MMP), mitochondrial mass and lysosomal mass by flow cytometry. Mitochondrial oxygen consumption rate (OCR) was recorded using Seahorse XF flux analyzer.

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Diabetic retinopathy (DR) is a major cause of blindness in adult, and the accumulation of advanced glycation end products (AGEs) is a major pathologic event in DR. Methylglyoxal (MGO), a highly reactive dicarbonyl compound, is a precursor of AGEs. Although the therapeutic potential of metformin for retinopathy disorders has recently been elucidated, possibly through AMPK activation, it remains unknown how metformin directly affects the MGO-induced stress response in retinal pigment epithelial cells.

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Adenosine triphosphate (ATP) released from dying cells with high concentrations is sensed as a danger signal by the P2X7 receptor. Sodium iodate (NaIO) is an oxidative toxic agent, and its retinal toxicity has been used as the model of dry age-related macular degeneration (AMD). In this study, we used NaIO-treated mice and cultured retinal cells, including BV-2 microglia, 661W photoreceptors, rMC1 Müller cells and ARPE-19 retinal epithelial cells, to understand the pathological action of P2X7 in retinal degeneration.

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Oxidative stress-associated retinal pigment epithelium (RPE) cell death is critically implicated in the pathogenesis of visual dysfunction and blindness of retinal degenerative diseases. Sodium iodate (NaIO) is an oxidative retinotoxin and causes RPE damage. Previously, we found that NaIO can induce human ARPE-19 cell death via inducing mitochondrial fission and mitochondrial dysfunction.

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Background: Vascular endothelial growth factor (VEGF) is upregulated by hypoxia and is a crucial stimulator for choroidal neovascularization (CNV) in age-related macular degeneration and pathologic myopia, as well as retinal neovascularization in proliferative diabetic retinopathy. Retinal and choroidal endothelial cells play key roles in the development of retinal and CNV, and subsequent fibrosis. At present, the effects of gold nanoparticles (AuNPs) on the VEGF-induced choroid-retina endothelial (RF/6A) cells are still unknown.

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After the publication of this article [1], the authors would like to clarify that some immunoblotting data in Figs. 2f, 3a and 4b were obtained from the same samples but individual SDS-PAGE gels.

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Background: Oxidative stress is a major factor in retinal pigment epithelium (RPE) cells injury that contributes to age-related macular degeneration (AMD). NaIO3 is an oxidative toxic agent and its selective RPE cell damage makes it as a reproducible model of AMD. Although NaIO3 is an oxidative stress inducer, the roles of ROS in NaIO3-elicited signaling pathways and cell viability have not been elucidated, and the effect of NaIO3 on autophagy in RPE cells remains elusive.

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Graphite oxide powder was obtained using the modified Hummers' method and characterized using X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The XPS results indicated that the epoxy groups were the main functional groups on the graphite oxide powder surface. The graphite oxide powder was then reacted with SO and NH gases, respectively, at 25 °C.

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The surface properties of polymer blends are important for many industrial applications. The physical and chemical properties at the surface of polymer blends can be drastically different from those in the bulk due to the surface segregation of the low surface energy component. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary mass spectrometry (ToF-SIMS) have been widely used to characterize surface and bulk properties.

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The surface chain conformations of poly(methyl methacrylate) (PMMA) at different temperatures were extensively studied by time-of-flight secondary ion mass spectrometry (ToF-SIMS). Similar to our previous experimental studies on polystyrene (PS) and poly(2, 3, 4, 5, 6-pentafluorostyrene) (5FPS), a transition temperature (T) could be identified through the principal component analysis (PCA) of the ToF-SIMS spectra obtained from the PMMA samples annealed at different temperatures. Interestingly, our results show that the T depended on molecular weight and was about 50-60˚C below the bulk glass transition temperature (T) and therefore could possibly be related to the surface glass transition temperature (T).

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Diabetic retinopathy (DR) and age-related macular degeneration (AMD) are two important leading causes of acquired blindness in developed countries. As accumulation of advanced glycation end products (AGEs) in retinal pigment epithelial (RPE) cells plays an important role in both DR and AMD, and the methylglyoxal (MGO) within the AGEs exerts irreversible effects on protein structure and function, it is crucial to understand the underlying mechanism of MGO-induced RPE cell death. Using ARPE-19 as the cell model, this study revealed that MGO induces RPE cell death through a caspase-independent manner, which relying on reactive oxygen species (ROS) formation, mitochondrial membrane potential (MMP) loss, intracellular calcium elevation and endoplasmic reticulum (ER) stress response.

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Aims: There is growing evidence of an increased prevalence of osteoarthritis (OA) among people with diabetes. Synovial inflammation and increased expression of cyclooxygenase-2 (COX-2) are two key features of patients with OA. Methylglyoxal (MGO) is a common intermediate in the formation of advanced glycation end-products, and its concentration is also typically higher in diabetes.

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Ultraviolet radiation, especially UVA, can penetrate the lens, reach the retina, and induce oxidative stress to retinal pigment epithelial (RPE) cells. Even though it is weakly absorbed by protein and DNA, it may trigger the production of reactive oxygen species (ROS) and generate oxidative injury; oxidative injury to the retinal pigment epithelium has been implicated to play a contributory role in age-related macular degeneration (AMD). Studies showed that resveratrol, an abundant and active component of red grapes, can protect several cell types from oxidative stress.

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During the course of proliferative vitreoretinopathy (PVR), the retinal pigment epithelium (RPE) cells will de-differentiate, proliferate, and migrate onto the surfaces of the sensory retina. Several studies have shown that platelet-derived growth factor (PDGF) can induce migration of RPE cells via an Akt-related pathway. In this study, the effect of lutein on PDGF-BB-induced RPE cells migration was examined using transwell migration assays and Western blot analyses.

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Poly (2, 3, 4, 5, 6-pentafluorostyrene) (5FPS) was prepared by bulk radical polymerization. The spin-cast films of this polymer were analyzed using time-of-flight secondary ion mass spectrometry (ToF-SIMS) at various temperatures ranging from room temperature to 120°C. Principal component analysis (PCA) of the ToF-SIMS data revealed a transition temperature (T(T)) at which the surface structure of 5FPS was rearranged.

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Time-of-flight secondary ion mass spectrometry (TOF-SIMS) spectra of polystyrene (PS) films supported on silicon wafers were obtained at temperatures ranging from room temperature to 100 °C. Principal component analysis (PCA) of the TOF-SIMS data revealed a transition temperature (TT) at which the surface structure of PS was rearranged. The TT of a 120-nm thick PS (weight-average molecular weight of 3,000 g/mol) thin film was determined to be about 36 °C, which is approximately 30 °C lower than the bulk glass transition temperature (Tg) of that PS.

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Purpose: In diseases such as proliferative vitreoretinopathy (PVR), proliferative diabetic retinopathy, and age-related macular degeneration, retinal pigment epithelial (RPE) cells proliferate and migrate. Moreover, platelet-derived growth factor (PDGF) has been shown to enhance proliferation and migration of RPE cells in PVR. Even resveratrol can suppress the migration and adhesion of many cell types, its effects on RPE cell migration and adhesion remain unknown.

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Purpose: To evaluate the midterm clinical and angiographic outcomes after pipeline embolization device (PED) placement for treatment of intracranial aneurysms.

Materials And Methods: This prospective nonrandomized multicenter study was approved by the review boards of all involved centers; informed consent was obtained. Patients (143 patients, 178 aneurysms) with unruptured saccular or fusiform aneurysms or recurrent aneurysms after previous treatment were included and observed angiographically for up to 18 months and clinically for up to 3 years.

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Surface patterns were observed on spin-coated poly(bisphenol A decane ether) (BA-C10) films prepared with chloroform and tetrahydrofuran as the solvents. The interior structure of these surface patterns were analyzed using a time-of-flight secondary ion mass spectrometry (ToF-SIMS) equipped with a bismuth cluster source for ion imaging and a C(60)(+) cluster source for depth profiling. For the first time, the surface patterns have been shown to be hollow rather than solid using ToF-SIMS three-dimensional (3D) analysis and optical techniques.

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