1.Brain Metabolite Changes in Insomnia and Obstructive Sleep Apnea
Haejin HONG ; Hyangwon LEE ; Sujung YOON ; Jungyoon KIM
Sleep Medicine and Psychophysiology 2021;28(1):18-26
Sleep is essential to brain function and mental health. Insomnia and obstructive sleep apnea (OSA) are the two most common sleep disorders, and are major public health concerns. Proton magnetic resonance spectroscopy (1H-MRS) is a non-invasive method of quantifying neurometabolite concentrations. Therefore, 1H-MRS studies on individuals with sleep disorders may enhance our understanding of the pathophysiology of these disorders. In this article, we reviewed 1H-MRS studies in insomnia and OSA that reported changes in neurometabolite concentrations. Previous studies have consistently reported insomnia-related reductions in γ-aminobutyric acid (GABA) levels in the frontal and occipital regions, which suggest that changes in GABA are important to the etiology of insomnia. These results may support the hyperarousal theory that insomnia is associated with increased cognitive and physiological arousal. In addition, the severity of insomnia was associated with low glutamate and glutamine levels. Previous studies of OSA have consistently reported reduced N-acetylaspartate (NAA) levels in the frontal, parietooccipital, and temporal regions. In addition, OSA was associated with increased myo-inositol levels. These results may provide evidence that intermittent hypoxia induced by OSA may result in neuronal damage in the brain, which can be related to neurocognitive dysfunction in patients with OSA. The current review summarizes findings related to neurochemical changes in insomnia and OSA. Future well-designed studies using 1H-MRS have the potential to enhance our understanding of the pathophysiology of sleep disorders including insomnia and OSA.
2.Brain Metabolite Changes in Insomnia and Obstructive Sleep Apnea
Haejin HONG ; Hyangwon LEE ; Sujung YOON ; Jungyoon KIM
Sleep Medicine and Psychophysiology 2021;28(1):18-26
Sleep is essential to brain function and mental health. Insomnia and obstructive sleep apnea (OSA) are the two most common sleep disorders, and are major public health concerns. Proton magnetic resonance spectroscopy (1H-MRS) is a non-invasive method of quantifying neurometabolite concentrations. Therefore, 1H-MRS studies on individuals with sleep disorders may enhance our understanding of the pathophysiology of these disorders. In this article, we reviewed 1H-MRS studies in insomnia and OSA that reported changes in neurometabolite concentrations. Previous studies have consistently reported insomnia-related reductions in γ-aminobutyric acid (GABA) levels in the frontal and occipital regions, which suggest that changes in GABA are important to the etiology of insomnia. These results may support the hyperarousal theory that insomnia is associated with increased cognitive and physiological arousal. In addition, the severity of insomnia was associated with low glutamate and glutamine levels. Previous studies of OSA have consistently reported reduced N-acetylaspartate (NAA) levels in the frontal, parietooccipital, and temporal regions. In addition, OSA was associated with increased myo-inositol levels. These results may provide evidence that intermittent hypoxia induced by OSA may result in neuronal damage in the brain, which can be related to neurocognitive dysfunction in patients with OSA. The current review summarizes findings related to neurochemical changes in insomnia and OSA. Future well-designed studies using 1H-MRS have the potential to enhance our understanding of the pathophysiology of sleep disorders including insomnia and OSA.
3.The effect of saliva decontamination procedures on dentin bond strength after universal adhesive curing.
Jayang KIM ; Sungok HONG ; Yoorina CHOI ; Sujung PARK
Restorative Dentistry & Endodontics 2015;40(4):299-305
OBJECTIVES: The purpose of this study was to investigate the effectiveness of multiple decontamination procedures for salivary contamination after curing of a universal adhesive on dentin bond strength according to its etch modes. MATERIALS AND METHODS: Forty-two extracted bovine incisors were trimmed by exposing the labial dentin surfaces and embedded in cylindrical molds. A universal adhesive (All-Bond Universal, Bisco) was used. The teeth were randomly divided into groups according to etch mode and decontamination procedure. The adhesive was applied according to the manufacturer's instructions for a given etch mode. With the exception of the control groups, the cured adhesive was contaminated with saliva for 20 sec. In the self-etch group, the teeth were divided into three groups: control, decontamination with rinsing and drying, and decontamination with rinsing, drying, and adhesive. In the etch-and-rinse group, the teeth were divided into four groups: control, decontamination with rinsing and drying, decontamination with rinsing, drying, and adhesive, and decontamination with rinsing, drying, re-etching, and reapplication of adhesive. A composite resin (Filtek Z350XT, 3M ESPE) was used for filling and was cured on the treated surfaces. Shear bond strength was measured, and failure modes were evaluated. The data were subjected to one-way analysis of variation and Tukey's HSD test. RESULTS: The etch-and-rinse subgroup that was decontaminated by rinse, drying, re-etching, and reapplication of adhesive showed a significantly higher bond strength. CONCLUSIONS: When salivary contamination occurs after curing of the universal adhesive, additional etching improves the bond strength to dentin.
Adhesives*
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Decontamination*
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Dentin*
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Fungi
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Incisor
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Saliva*
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Tooth
4.Cognitive Enhancement in Neurological and Psychiatric Disorders Using Transcranial Magnetic Stimulation (TMS): A Review of Modalities, Potential Mechanisms and Future Implications
Tammy D KIM ; Gahae HONG ; Jungyoon KIM ; Sujung YOON
Experimental Neurobiology 2019;28(1):1-16
Cognitive enhancement refers to the improvement of cognitive function related to deficits that occurred as part of a certain illness. However, the term cognitive enhancement does not yet have a definitive meaning, and its connotations often vary depending on the research of interest. Recently, research interests are growing towards enhancing human cognition beyond what has traditionally been considered necessary using various brain devices. The phenomenon of exceeding the cognitive abilities of individuals who are already functional has also introduced new terminologies as means to classify between cognitive enhancing procedures that are part of treatment versus simply supplementary. Of the many devices used to attain cognitive enhancement, transcranial magnetic stimulation (TMS) is a unique neurostimulatory device that has demonstrated significant improvements in various cognitive domains including memory and cognitive processing skills. While many studies have supported the safety and efficacy of TMS in treatment, there has yet to be an optimization in parameter for TMS that is catered to a certain target group. The current paper aims to review with perspective the many studies that have used TMS for the purpose of cognitive enhancement and provide further insight on the development of an optimal stimulation parameter. The paper reviews 41 peer-reviewed articles that used TMS for cognitive enhancement, summarizes the findings that were apparent for each distinct parameter, and discusses future directions regarding TMS as an elective tool for healthy individuals while considering some of the ethical perspectives that may be warranted.
Brain
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Cognition
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Humans
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Memory
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Neuropsychological Tests
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Transcranial Magnetic Stimulation
5.A Novel Pancreatic Imaging Window for Stabilized Longitudinal In Vivo Observation of Pancreatic Islets in Murine Model
Inwon PARK ; Sujung HONG ; Yoonha HWANG ; Pilhan KIM
Diabetes & Metabolism Journal 2020;44(1):193-198
Longitudinal imaging of murine pancreas is technically challenging due to the mechanical softness of the tissue influenced by peristalsis. Here, we report a novel pancreatic imaging window for long-term stabilized cellular-level observation of the islets in the pancreas in vivo. By spatially separating the pancreas from the bowel movement and physiologic respiration with a metal plate integrated in the imaging window, we successfully tracked the pancreatic islets up to three weeks and visualized the dumbbell-shape transformation from the single islet. This window can be a useful tool for long-term cellular-level visualization of the microstructure in the pancreas.
6.Changes in Structural Covariance among Olfactory-related Brain Regions in Anosmia Patients
Suji LEE ; Yumi SONG ; Haejin HONG ; Yoonji JOO ; Eunji HA ; Youngeun SHIM ; Seung-No HONG ; Jungyoon KIM ; In Kyoon LYOO ; Sujung YOON ; Dae Woo KIM
Experimental Neurobiology 2024;33(2):99-106
Anosmia, characterized by the loss of smell, is associated not only with dysfunction in the peripheral olfactory system but also with changes in several brain regions involved in olfactory processing. Specifically, the orbitofrontal cortex is recognized for its pivotal role in integrating olfactory information, engaging in bidirectional communication with the primary olfactory regions, including the olfactory cortex, amygdala, and entorhinal cortex. However, little is known about alterations in structural connections among these brain regions in patients with anosmia. In this study, highresolution T1-weighted images were obtained from participants. Utilizing the volumes of key brain regions implicated in olfactory function, we employed a structural covariance approach to investigate brain reorganization patterns in patients with anosmia (n=22) compared to healthy individuals (n=30). Our structural covariance analysis demonstrated diminished connectivity between the amygdala and entorhinal cortex, components of the primary olfactory network, in patients with anosmia compared to healthy individuals (z=-2.22, FDR-corrected p=0.039). Conversely, connectivity between the orbitofrontal cortex—a major region in the extended olfactory network—and amygdala was found to be enhanced in the anosmia group compared to healthy individuals (z=2.32, FDR-corrected p=0.039). However, the structural connections between the orbitofrontal cortex and entorhinal cortex did not differ significantly between the groups (z=0.04, FDR-corrected p=0.968). These findings suggest a potential structural reorganization, particularly of higher-order cortical regions, possibly as a compensatory effort to interpret the limited olfactory information available in individuals with olfactory loss.
7.Aberrant Resting-state Functional Connectivity in Complex Regional Pain Syndrome: A Network-based Statistics Analysis
Haejin HONG ; Chaewon SUH ; Eun NAMGUNG ; Eunji HA ; Suji LEE ; Rye Young KIM ; Yumi SONG ; Sohyun OH ; In Kyoon LYOO ; Hyeonseok JEONG ; Sujung YOON
Experimental Neurobiology 2023;32(2):110-118
Complex regional pain syndrome (CRPS) is a chronic neuropathic pain disorder. Pain catastrophizing, characterized by magnification, rumination, and helplessness, increases perceived pain intensity and mental distress in CRPS patients. As functional connectivity patterns in CRPS remain largely unknown, we aimed to investigate functional connectivity alterations in CRPS patients and their association with pain catastrophizing using a whole-brain analysis approach. Twenty-one patients with CRPS and 49 healthy controls were included in the study for clinical assessment and resting-state functional magnetic resonance imaging. Between-group differences in whole-brain functional connectivity were examined through a Network-based Statistics analysis. Associations between altered functional connectivity and the extent of pain catastrophizing were also assessed in CRPS patients. Relative to healthy controls, CRPS patients showed higher levels of functional connectivity in the bilateral somatosensory subnetworks (components 1~2), but lower functional connectivity within the prefronto-posterior cingulate (component 3), prefrontal (component 4), prefronto-parietal (component 5), and thalamo-anterior cingulate (component 6) subnetworks (p<0.05, family-wise error corrected). Higher levels of functional connectivity in components 1~2 (β=0.45, p=0.04) and lower levels of functional connectivity in components 3~6 (β=-0.49, p=0.047) were significantly correlated with higher levels of pain catastrophizing in CRPS patients. Higher functional connectivity in the somatosensory subnetworks implicating exaggerated pain perception and lower functional connectivity in the prefronto-parieto-cingulo-thalamic subnetworks indicating impaired cognitive-affective pain processing may underlie pain catastrophizing in CRPS.
8.Alterations in Brain Morphometric Networks and Their Relationship with Memory Dysfunction in Patients with Type 2 Diabetes Mellitus
Rye Young KIM ; Yoonji JOO ; Eunji HA ; Haejin HONG ; Chaewon SUH ; Youngeun SHIM ; Hyeonji LEE ; Yejin KIM ; Jae-Hyoung CHO ; Sujung YOON ; In Kyoon LYOO
Experimental Neurobiology 2024;33(2):107-117
Cognitive dysfunction, a significant complication of type 2 diabetes mellitus (T2DM), can potentially manifest even from the early stages of the disease. Despite evidence of global brain atrophy and related cognitive dysfunction in early-stage T2DM patients, specific regions vulnerable to these changes have not yet been identified. The study enrolled patients with T2DM of less than five years’ duration and without chronic complications (T2DM group, n=100) and demographically similar healthy controls (control group, n=50). High-resolution T1-weighted magnetic resonance imaging data were subjected to independent component analysis to identify structurally significant components indicative of morphometric networks. Within these networks, the groups’ gray matter volumes were compared, and distinctions in memory performance were assessed. In the T2DM group, the relationship between changes in gray matter volume within these networks and declines in memory performance was examined. Among the identified morphometric networks, the T2DM group exhibited reduced gray matter volumes in both the precuneus (Bonferronicorrected p=0.003) and insular-opercular (Bonferroni-corrected p=0.024) networks relative to the control group. Patients with T2DM demonstrated significantly lower memory performance than the control group (p=0.001). In the T2DM group, reductions in gray matter volume in both the precuneus (r=0.316, p=0.001) and insular-opercular (r=0.199, p=0.047) networks were correlated with diminished memory performance. Our findings indicate that structural alterations in the precuneus and insular-opercular networks, along with memory dysfunction, can manifest within the first 5 years following a diagnosis of T2DM.
9.Antitumor effect of TW-37, a BH3 mimetic in human oral cancer
Chi Hyun AHN ; Won Woo LEE ; Yun Chan JUNG ; Ji Ae SHIN ; Kyoung Ok HONG ; Sujung CHOI ; Neeti SWARUP ; Jihoon KIM ; Min Hye AHN ; Minjung JUNG ; Sung Dae CHO ; Bohwan JIN
Laboratory Animal Research 2019;35(4):194-201
TW-37 is a small molecule B cell lymphoma-2 (Bcl-2) homology 3 mimetic with potential anticancer activities. However, the in vivo anti-cancer effect of TW-37 in human oral cancer has not been properly studied yet. Here, we attempted to confirm antitumor activity of TW37 in human oral cancer. TW-37 significantly inhibited cell proliferation and increased the number of dead cells in MC-3 and HSC-3 human oral cancer cell lines. TW-37 enhanced apoptosis of both cell lines evidenced by annexin V/propidium iodide double staining, sub-G1 population analysis and the detection of cleaved poly (ADP-ribose) polymerase and caspase-3. In addition, TW-37 markedly downregulated the expression of Bcl-2 protein, while not affecting Bcl-xL or myeloid cell leukemia-1. In vivo, TW-37 inhibited tumor growth in a nude mice xenograft model without any significant liver and kidney toxicities. Collectively, these data reveal that TW-37 may be a promising small molecule to inhibit human oral cancer.
Animals
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Apoptosis
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Caspase 3
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Cell Line
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Cell Proliferation
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Heterografts
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Humans
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Kidney
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Liver
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Mice
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Mice, Nude
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Mouth Neoplasms
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Myeloid Cells
10.Longitudinal Intravital Imaging of Tumor-Infiltrating Lymphocyte Motility in Breast Cancer Models
Inwon PARK ; Sujung HONG ; Joon SEOK ; Stephani Edwina LUCIA ; Eunjoo SONG ; Mingyo KIM ; Eunji KONG ; Howon SEO ; Yoonha HWANG ; Soyeon AHN ; Seonghye KIM ; Dong-Hyun JANG ; Jae Hyuk LEE ; Su-Hyung PARK ; Pilhan KIM ; You Hwan JO
Journal of Breast Cancer 2021;24(5):463-473
Immunoreactive dynamics of tumor-infiltrating lymphocytes (TILs) within the tumor microenvironment in breast cancer are not well understood. This study aimed to investigate the spatiotemporal cellular dynamics of TILs in breast cancer models. Breast cancer cells were implanted into the dorsal skinfold chamber of BALB/c nude mice, and T lymphocytes were adoptively transferred. Longitudinal intravital imaging was performed, and the spatiotemporal dynamics of TILs were assessed. In the 4T1 model, TILs progressively exhibited increased motility, and their motility inside the tumor was significantly higher than that outside the tumor. In the MDA-MB-231 model, the motility of TILs progressively decreased after an initial increase. TIL motility in the MDA-MB-231 and MCF-7 models differed significantly, suggesting an association between programmed death-ligand 1 expression levels and TIL motility, which warrants further investigation. Furthermore, intravital imaging of TILs can be a useful method for addressing dynamic interactions between TILs and breast cancer cells.