Publications by authors named "Min-Suk Kang"

Article Synopsis
  • Blood-based biomarkers like p-tau217 are being studied for their effectiveness in diagnosing Alzheimer's disease (AD), but previous research has mainly focused on non-Hispanic White populations, leading to a knowledge gap across different ethnic backgrounds.
  • A new study involving Peruvians, including mestizos and indigenous groups, examined plasma p-tau217 in 525 individuals, revealing significant associations between the biomarker and AD, especially in those with the APOE-e4 allele, although it did not distinguish between healthy controls and mild cognitive impairment (MCI).
  • The results indicated that p-tau217 levels correlated well with cognitive performance and had an impressive classification performance (ROC-AUC of 82.82%), marking a significant contribution to understanding AD in diverse
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In this study, the effects of the length-to-width ratio on the magnetic and microstructural properties of die-upset Nd-Fe-B magnets were examined. A die-upset magnet with a uniform shape and no significant cracking was successfully developed. During the die-upset process, the applied pressure was not uniform across the magnet and varied depending on its shape and position.

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Article Synopsis
  • - Research on patients with normal pressure hydrocephalus (NPH) indicates that early Alzheimer's disease (AD) pathology can be detected, and this study aims to identify cerebrospinal fluid (CSF) biomarkers related to these initial AD changes.
  • - The study analyzed CSF data and found that specific biomarkers such as β-amyloid-42/40 and neurofilament light chain (NfL) are correlated with AD pathology; seven key proteins were identified that also relate to both pathology and gene expression.
  • - The findings suggest a link between CSF biomarkers and central nervous system changes in AD, providing valuable insights into how these markers reflect the disease's progression.
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Introduction: Normal pressure hydrocephalus (NPH) patients undergoing cortical shunting frequently show early AD pathology on cortical biopsy, which is predictive of progression to clinical AD. The objective of this study was to use samples from this cohort to identify CSF biomarkers for AD-related CNS pathophysiologic changes using tissue and fluids with early pathology, free of post-mortem artifact.

Methods: We analyzed Simoa, proteomic, and metabolomic CSF data from 81 patients with previously documented pathologic and transcriptomic changes.

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This article presents a practical guide to mass spectrometry-based data-independent acquisition and label-free quantification for proteomics analysis applied to cerebrospinal fluid, offering a robust and scalable approach to probing the proteomic composition of the central nervous system. © 2024 Wiley Periodicals LLC. Basic Protocol 1: Cerebrospinal fluid sample collection and preparation for mass spectrometry analysis Basic Protocol 2: Mass spectrometry sample analysis with data-independent acquisition Support Protocol: Data-dependent mass spectrometry and spectral library construction Basic Protocol 3: Analysis of mass spectrometry data.

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Background: Alzheimer's disease (AD) biomarkers can help differentiate cognitively unimpaired (CU) individuals from mild cognitive impairment (MCI) and dementia. The role of AD biomarkers in predicting cognitive impairment and AD needs examination.

Methods: In 628 CU individuals from a multi-ethnic cohort, amyloid beta (Aβ)42, Aβ40, phosphorylated tau-181 (p-tau181), glial fibrillary acidic protein (GFAP), and neurofilament light chain (NfL) were measured in plasma.

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Introduction: Alzheimer's disease (AD) biomarkers can help differentiate cognitively unimpaired (CU) individuals from mild cognitive impairment (MCI) and dementia. The role of AD biomarkers in predicting cognitive impairment and AD needs examination.

Methods: In 628 CU individuals from a multi-ethnic cohort, Aβ42, Aβ40, phosphorylated tau-181 (P-tau181), glial fibrillary acid protein (GFAP), and neurofilament light chain (NfL) were measured in plasma.

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Cerebrovascular injury frequently occurs in children with sickle cell anaemia (SCA). Limited access to magnetic resonance imaging and angiography (MRI-MRA) in sub-Saharan Africa impedes detection of clinically unapparent cerebrovascular injury. Blood-based brain biomarkers of cerebral infarcts have been identified in non-SCA adults.

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Importance: Cerebrospinal fluid (CSF) and plasma biomarkers can detect biological evidence of Alzheimer disease (AD), but their use in low-resource environments and among minority ethnic groups is limited.

Objective: To assess validated plasma biomarkers for AD among adults of Caribbean Hispanic ethnicity.

Design, Setting, And Participants: In this decision analytical modeling study, adults were recruited between January 1, 2018, and April 30, 2022, and underwent detailed clinical assessments and venipuncture.

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Predictive tracking demonstrates our ability to maintain a line of vision on moving objects even when they temporarily disappear. Models of smooth pursuit eye movements posit that our brain achieves this ability by directly streamlining motor programming from continuously updated sensory motion information. To test this hypothesis, we obtained sensory motion representation from multivariate electroencephalogram activity while human participants covertly tracked a temporarily occluded moving stimulus with their eyes remaining stationary at the fixation point.

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The human ventromedial prefrontal cortex (vmPFC) has been traditionally associated with decision-making under risk. Neuroimaging studies of such decision-making processes have largely focused on patients with vmPFC lesions or pathological gambling behavior, leading to a relative paucity of work focusing on the structural variability of the vmPFC in healthy individuals. To address this, we developed a decision-making task that allowed healthy players to choose to participate in either low stakes or high-stakes gambling on a trial-by-trial basis, and computed a metric that indexes the propensity for engaging in gambles with greater potential payoffs.

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Background: Posttraumatic stress disorder (PTSD) is associated with cognitive decline and risk for dementia, but the neuropathology involved is unclear.

Objective: The aim of this study was to determine whether PTSD is associated with increased levels of Alzheimer's disease (AD) blood-based biomarkers.

Methods: Individuals aged 50 years and older with PTSD were compared to trauma-exposed healthy controls (TEHCs) at baseline on serum measures of amyloid- (A) 42 and 40 levels, the A /A ratio, and total tau.

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Blood-based phosphorylated tau (Ptau) 181 and 217 biomarkers are sensitive and specific for Alzheimer's disease. In this racial/ethnically diverse cohort study, participants were classified as biomarker positive (Ptau+) or negative (Ptau-) based on Ptau 181 and 217 concentrations and as cognitively impaired (Sym) or unimpaired (Asym). The four groups, Ptau-/Asym, Ptau+/Asym, Ptau-/Sym, and Ptau+/Sym, differed by age, APOE-4 allele frequency, total tau, neurofilament light chain, and cortical thickness measured by MRI.

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Background: Elastic ear cartilage is a good source of tissue for support or augmentation in plastic and reconstructive surgery. However, the amount of ear cartilage is limited and excessive use of cartilage can cause deformation of the auricular framework. This animal study investigated the potential of periosteal chondrogenesis in an ear cartilage defect model.

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Article Synopsis
  • The study investigates how the brain processes groups of similar visual stimuli to understand ensemble coding, specifically looking at how task relevance affects this process.
  • Researchers used fMRI to track brain responses, finding that orientation-selective activity increased in the visual hierarchy only when the average orientation was important for the task.
  • The results indicate that while ensemble representations are present even without task relevance in areas like the extrastriate region (V3), they are more pronounced in frontal regions when linked to motor responses, suggesting a complex pooling of visual information across different processing levels.
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Article Synopsis
  • Visual working memory (VWM) helps us hold a limited amount of visual info, but there's debate on how it's organized, with object-based theories claiming integration of features and feature-based theories suggesting independent representation.
  • Recent studies show features of an object can be forgotten independently, challenging the idea of perfect integration, but it's possible that features are still related when objects are remembered.
  • By creating a new task to assess two features at the same time, researchers found that feature representations are more dependent when processed simultaneously compared to sequentially, indicating a complex organization of features in VWM.
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Background: Leucine-rich repeat kinase 2 kinase inhibitors are being vigorously pursued as potential therapeutic options; however, there is a critical need for sensitive and quantitative assays of leucine-rich repeat kinase 2 function and target engagement.

Objectives: Our objective was to compare collection and storage protocols for peripheral blood mononuclear cells, and to determine the optimal conditions for downstream analyses of leucine-rich repeat kinase 2 in PD cohorts.

Methods: Here, we describe enzyme-linked immunosorbent assay-based assays capable of detecting multiple aspects of leucine-rich repeat kinase 2 function at endogenous levels in human tissues.

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Proactive control reflects a sustained, top-down maintenance of a goal representation prior to task-related events, whereas reactive control reflects a transient, bottom-up goal reactivation in response to them. We designed a manual stop-signal task to isolate electrophysiological signals specifically involved in proactive control. Participants performed a simple choice reaction time task but had to withhold their response to an infrequent stop signal, resulting in go- and stop-signal trials.

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We characterized the population-level neural coding of ensemble representations in visual working memory from human electroencephalography. Ensemble representations provide a unique opportunity to investigate structured representations of working memory because the visual system encodes high-order summary statistics as well as noisy sensory inputs in a hierarchical manner. Here, we consistently observe stable coding of simple features as well as the ensemble mean in frontocentral electrodes, which even correlated with behavioral indices of the ensemble across individuals.

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We investigated whether clustering based on feature similarity improves the representational quality of visual working memory (VWM). We hypothesized that similar items are organized into clusters, and their recall precision increases with fewer clusters because of reduced memory load. In a series of 6 experiments, participants remembered orientations or colors of several stimuli and estimated the orientation (color) of cued item(s).

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Brightness of an object is determined by various factors including ambient illumination, surface reflectance of the object, and spatial and temporal relation between the object and its surrounding context. Recently, it has been demonstrated that the motion of an object alters its own and nearby object's appearance such as brightness and color. This study aims to unveil mechanisms of the motion-induced brightness shift by measuring its temporal dynamics.

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The objective of the present study was to examine the effects of different muscle contraction interventions using isokinetic dynamometers on the muscle recovery after muscle injury caused by eccentric exercise. A total of 28 healthy male adults participated in the present study and each subject was randomly assigned to eccentric muscle contraction (EC, n=7), concentric muscle contraction (CC, n=7), both eccentric and concentric muscle contraction (BEC, n=7), and control (CON, n=7) groups after performing eccentric exercise. In all groups, except the control group, a different type of muscle contraction intervention was applied repeatedly for 24-96 hr after eccentric exercise, and maximum strength, muscle soreness, and creatine kinase (CK) levels were measured.

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As documented by Darwin 150 years ago, emotion expressed in human faces readily draws our attention and promotes sympathetic emotional reactions. How do such reactions to the expression of emotion affect our goal-directed actions? Despite the substantial advance made in the neural mechanisms of both cognitive control and emotional processing, it is not yet known well how these two systems interact. Here, we studied how emotion expressed in human faces influences cognitive control of conflict processing, spatial selective attention and inhibitory control in particular, using the Eriksen flanker paradigm.

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We often shift our eyes to an interesting stimulus, but it is important to inhibit that eye movement in some environments (e.g., a no-look pass in basketball).

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Chromatic induction compellingly demonstrates that chromatic context as well as spectral lights reflected from an object determines its color appearance. Here, we show that when one colored object moves around an identical stationary object, the perceived saturation of the stationary object decreases dramatically whereas the saturation of the moving object increases. These color appearance shifts in the opposite directions suggest that normalization induced by the object's motion may mediate the shift in color appearance.

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