Publications by authors named "Euiheon Chung"

Photoacoustic tomography (PAT) combines high optical contrast with deep acoustic penetration, making it valuable for biomedical imaging. However, all-optical systems often face challenges in measuring the acoustic wave-induced displacements on rough and dynamic tissues surfaces. We present an all-optical PAT system enabling fast and high-resolution volumetric imaging .

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Ischemic stroke often leads to neurological deficits, including olfactory dysfunction, which can significantly diminish quality of life. Photobiomodulation (PBM) has emerged as a promising therapeutic strategy for enhancing post-stroke recovery, although the molecular mechanisms, particularly regarding gene expression change, are not yet fully understood. This study investigates the long-term effects of photothrombosis (PT) on olfactory function and the olfactory bulb (OB) microenvironment, with a focus on PBM's efficacy during both early and late phases.

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Diabetic neuropathy (DN) is a prevalent and debilitating complication of diabetes, significantly impairing quality of life through chronic pain, sensory deficits, and motor dysfunction. Despite its widespread impact, current rodent behavioral assessments using 2D tracking methods primarily quantify basic locomotion, such as distance and speed, but lack resolution to detect subtle, pattern-based motor impairments characteristic of DN. This study employed MoSeq-based 3D behavioral profiling combined with unsupervised machine learning to identify subtle yet significant alterations in nicotinamide (NA)- and streptozotocin (STZ)-induced DN mouse models.

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Objectives: To compare the effects of general and regional anesthesia on clinical outcomes following primary total hip arthroplasty (THA).

Methods: This retrospective study using data from the Korean National Health Insurance Research Database included 1,522 patients who underwent THA under general anesthesia ( = 640) or regional anesthesia ( = 882) between 2002 and 2015. We compared the mortality and complication rates within 30 days after surgery.

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Purpose: Neuropathic corneal pain (NCP) is a debilitating condition characterized by persistent pain due to corneal nerve damage or dysfunction. Millions of individuals and their families endure the significant impact of chronic pain. Effective management strategies are crucial yet limited, prompting the exploration of innovative treatments such as photobiomodulation (PBM).

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Alzheimer's disease (AD) is driven by complex interactions between vascular dysfunction, glymphatic system impairment, and neuroinflammation. Vascular aging, characterized by arterial stiffness and reduced cerebral blood flow (CBF), disrupts the pulsatile forces necessary for glymphatic clearance, exacerbating amyloid-beta (Aβ) accumulation and cognitive decline. This review synthesizes insights into the mechanistic crosstalk between these systems and explores their contributions to AD pathogenesis.

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Ultrasound neuromodulation (UNM) has gained significant interest in brain science due to its non-invasive nature, precision, and deep brain stimulation capabilities. However, the skull poses challenges along the acoustic path, leading to beam distortion and necessitating effective acoustic aberration correction. Acoustic holograms used with single-element ultrasound transducers offer a promising solution by enabling both aberration correction and multi-focal stimulation.

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Optical neuroimaging has significantly advanced our understanding of brain function, particularly through techniques such as two-photon microscopy, which captures three-dimensional brain structures with sub-cellular resolution. However, traditional methods struggle to record fast, complex neuronal interactions in real time, which are crucial for understanding brain networks and developing treatments for neurological diseases such as Alzheimer's, Parkinson's, and chronic pain. Recent advancements in ultrafast imaging technologies, including kilohertz two-photon microscopy, light field microscopy, and event-based imaging, are pushing the boundaries of temporal resolution in neuroimaging.

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Purpose: Neuropathic corneal pain (NCP) is a debilitating condition affecting millions of people worldwide. Despite their critical importance, currently available animal models for NCP research are limited by complex surgeries with high-risk strategy. To advance fundamental understanding of NCP, we developed a novel rodent model that explores both structural and functional mechanisms of the disease, offering a comprehensive approach.

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In optical imaging of solid tumors, signal contrasts derived from inherent tissue temperature differences have been employed to distinguish tumor masses from surrounding tissue. Moreover, with the advancement of active infrared imaging, dynamic thermal characteristics in response to exogenous thermal modulation (heating and cooling) have been proposed as novel measures of tumor assessment. Contrast factors such as the average rate of temperature changes and thermal recovery time constants have been investigated through an active thermal modulation imaging approach, yielding promising tumor characterization results in a xenograft mouse model.

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Article Synopsis
  • - Neuropathic pain results from hyperactive spinal dorsal horn neurons, leading to symptoms like allodynia, and the role of astrocyte-neuron interactions is not fully understood.
  • - Research found that reactive astrocytes release excessive GABA, which unexpectedly excites nearby neurons due to altered GABA processing mechanisms, linking astrocytic activity to increased neuronal hyperexcitability.
  • - Inhibiting monoamine oxidase B (MAOB) can reverse these changes, restoring normal GABA function, reducing glucose metabolism in the dorsal horn, and alleviating allodynia, suggesting that astrocytic GABA plays a crucial role in neuropathic pain.
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Background/aim: Urinary bladder cancer has various etiologies and tends to recur and then progress to a higher grade. When muscles are invaded, the response to conventional therapy is poor and the quality of life deteriorates rapidly. Here, we summarize and compare two representative methods used to create the syngeneic mouse models required for immunological research.

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Laser speckle imaging (LSI) techniques have emerged as a promising method for visualizing functional blood vessels and tissue perfusion by analyzing the speckle patterns generated by coherent light interacting with living biological tissue. These patterns carry important biophysical tissue information including blood flow dynamics. The noninvasive, label-free, and wide-field attributes along with relatively simple instrumental schematics make it an appealing imaging modality in preclinical and clinical applications.

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An ischemic stroke typically accompanies numerous disorders ranging from somatosensory dysfunction to cognitive impairments, inflicting patients with various neurologic symptoms. Among pathologic outcomes, post-stroke olfactory dysfunctions are frequently observed. Despite the well-known prevalence, therapy options for such compromised olfaction are limited, likely due to the complexity of olfactory bulb architecture, which encompasses both the peripheral and central nervous systems.

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In microscopic imaging of biological tissues, particularly real-time visualization of neuronal activities, rapid acquisition of volumetric images poses a prominent challenge. Typically, two-dimensional (2D) microscopy can be devised into an imaging system with 3D capability using any varifocal lens. Despite the conceptual simplicity, such an upgrade yet requires additional, complicated device components and usually suffers from a reduced acquisition rate, which is critical to properly document rapid neurophysiological dynamics.

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Diabetes mellitus accompanies an abnormally high glucose level in the bloodstream. Early diagnosis and proper glycemic management of blood glucose are essential to prevent further progression and complications. Biosensor-based colorimetric detection has progressed and shown potential in portable and inexpensive daily assessment of glucose levels because of its simplicity, low-cost, and convenient operation without sophisticated instrumentation.

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Optical neuroimaging provides an effective neuroscience tool for multi-scale investigation of the neural structures and functions, ranging from molecular, cellular activities to the inter-regional connectivity assessment. Amongst experimental preparations, the implementation of an artificial window to the central nervous system (CNS) is primarily required for optical visualization of the CNS and associated brain activities through the opaque skin and bone. Either thinning down or removing portions of the skull or spine is necessary for unobstructed long-term observations, for which types of the cranial and spinal window and applied materials vary depending on the study objectives.

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Purpose: Develop a deep learning-based automated method to segment meibomian glands (MG) and eyelids, quantitatively analyze the MG area and MG ratio, estimate the meiboscore, and remove specular reflections from infrared images.

Methods: A total of 1600 meibography images were captured in a clinical setting. 1000 images were precisely annotated with multiple revisions by investigators and graded 6 times by meibomian gland dysfunction (MGD) experts.

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Diabetes is a disease condition characterized by a prolonged, high blood glucose level, which may lead to devastating outcomes unless properly managed. Here, we introduce a simple camera-based optical monitoring system (OMS) utilizing the nanoparticle embedded contact lens that produces color changes matching the tear glucose level without any complicated electronic components. Additionally, we propose an image processing algorithm that automatically optimizes the measurement accuracy even in the presence of image blurring, possibly caused by breathing, subtle movements, and eye blinking.

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Open-top light-sheet microscopy (OT-LSM) is a specialized microscopic technique for high throughput cellular imaging of large tissue specimens including optically cleared tissues by having the entire optical setup below the sample stage. Current OT-LSM systems had relatively low axial resolutions by using weakly focused light sheets to cover the imaging field of view (FOV). In this report, open-top axially swept LSM (OTAS-LSM) was developed for high-throughput cellular imaging with improved axial resolution.

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Phototherapy is widely applied to various human diseases. Nanomedicine-based phototherapy can be classified into photodynamic therapy (PDT) and photothermal therapy (PTT). Activated photosensitizer kills the target cells by generating radicals or reactive oxygen species in PDT while generating heat in PTT.

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Trigeminal ganglion (TG) neurons play an essential role in the sensory nerves of the face. Damaged TG neurons resulting from the accidental and non-intentional nerve lesions, commonly identified as neuropathic pain, which is known to cause intense pain and sensory abnormalities. For the treatment, surgical methods are conducted when the pharmacological treatment fails to provide satisfactory recovery.

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Glucose level is a primary indicator in the diagnosis and treatment of diabetes mellitus. According to the correlation between glucose concentration in blood and tears, measuring tear glucose can be an alternative to traditional strips test for blood glucose. Thus, measuring tear glucose levels could provide noninvasive monitoring of blood glucose.

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Platelet aggregation and adhesion are critically involved in both normal hemostasis and thrombosis during vascular injury. Before any surgery, it is important to identify the number of platelets and their functionality to reduce the risk of bleeding; therefore, platelet function testing is a requirement. We introduce a novel evaluation method of assessing platelet function with laser speckle contrast imaging.

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