Publications by authors named "Younghoon Sung"

Introduction: Smoking-related diseases affect 16 million Americans, causing approximately 480,000 deaths annually. The prevalence of cigarette smoking varies regionally across the United States, and previous research indicates that regional rates of smoking-related diseases demonstrate a negative association with altitude. The purpose of this study was to determine the relationship between altitude and the prevalence of cigarette smoking by county ( = 3106) in the United States.

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In binocular animals that exhibit stereoscopic visual responses, the axons of retinal ganglion cells (RGCs) connect to brain areas bilaterally by forming a commissure called the optic chiasm (OC). Ventral anterior homeobox 1 (Vax1) contributes to the formation of the OC, acting endogenously in optic pathway cells and exogenously in growing RGC axons. Here, we generated Vax1 mice expressing the Vax1 mutant, which is incapable of intercellular transfer.

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Background: Cytidine-5'-diphosphate choline (CDP-choline) has been suggested to exert neuroprotective and neuroreparative effects and may be beneficial for patients with stimulant dependence. This randomized, double-blind, placebo-controlled study in methamphetamine (MA) dependence investigated effects of CDP-choline on the brain structures and their associations with craving and MA use.

Methods: MA users (n = 44) were randomized to receive 2 g/day of CDP-choline (n = 22) or placebo (n = 22) for 8 weeks.

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The primary purpose of this pilot study was to evaluate OULA®, a dance fitness program with a strong emphasis on processing emotions through dance, as an intervention for depression in women diagnosed with major or persistent depressive disorders. 53 women were eligible for participation. Women attended OULA® for 12 weeks and then abstained from OULA® during week 13.

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KRAS-mutant non-small cell lung cancer (NSCLC) is a major lung cancer subtype that leads to many cancer-related deaths worldwide. Although numerous studies on KRAS-mutant type NSCLC have been conducted, new oncogenic or tumor suppressive genes need to be detected because a large proportion of NSCLC patients does not respond to currently used therapeutics. Here, we show the tumor-promoting function of a cell cycle-related protein, PIERCE1, in KRAS-mutant NSCLC.

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Article Synopsis
  • Recent advances in coloring using nanostructures provide non-toxic, durable, and high-resolution alternatives to conventional pigments.
  • The asymmetric Fabry-Perot (FP) cavity absorber is highlighted for its manufacturability but traditionally lacked techniques for producing multi-color structures.
  • This study presents a method for creating colored reflective characters using UV imprint lithography, achieving high absorption and resolution, which could enhance reflective displays and color printing in various industries.
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Rational design of sulfur electrodes is exceptionally important in enabling a high-performance lithium/sulfur cell. Constructing a continuous pore structure of the sulfur electrode that enables facile lithium ion transport into the electrode and mitigates the reconstruction of sulfur is a key factor for enhancing the electrochemical performance. Here, we report a three-dimensionally (3D) aligned sulfur electrode cast onto conventional aluminum foil by directional freeze tape casting.

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Objective: Prescription opioid misuse and fatal overdoses have increased significantly over the last two decades. Living at altitude has been linked to greater reward benefits of other drugs of abuse, and living at altitude may also exacerbate the respiratory depression linked to opioid use. Therefore, we examined the relationships between living at altitude, and prescription opioid misuse and fatal overdoses.

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Aim: Increased oxidative stress in cerebral mitochondria may follow exposure to the systemic hypobaric hypoxia associated with residing at higher altitudes. Because mitochondrial dysfunction is implicated in bipolar disorder (BD) pathophysiology, this may impact the cerebral bioenergetics in BD. In this study, we evaluated the cerebral bioenergetics of BD and healthy control (HC) subjects at two sites, located at sea level and at moderate altitude.

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Objective: The purpose of this study was to test the initial psychometric properties of the 17-item Hamilton Depression Rating Scale (HAM-D) in individuals with and without major depressive disorder who use methamphetamine. We used data from two completed studies and two ongoing clinical trials. The HAM-D has well established reliability and validity in a variety of populations.

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Purpose: Many women with major depressive disorder (MDD) respond inadequately to standard treatments. Augmentation of conventional antidepressants with creatine monohydrate and 5-hydroxytryptophan (5-HTP) could correct deficits in serotonin production and brain bioenergetics associated with depression in women, yielding synergistic benefit. We describe an open-label study of 5-HTP and creatine augmentation in women with MDD who had failed selective serotonin reuptake inhibitor (SSRI) or serotonin-norepinephrine reuptake inhibitor (SNRI) monotherapy.

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Major depressive disorder (MDD) often begins during adolescence and is projected to become the leading cause of global disease burden by the year 2030. Yet, approximately 40 % of depressed adolescents fail to respond to standard antidepressant treatment with a selective serotonin reuptake inhibitor (SSRI). Converging evidence suggests that depression is related to brain mitochondrial dysfunction.

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Objectives: The aim of the present study was to measure brain phosphorus-31 magnetic resonance spectroscopy ((31) P MRS) metabolite levels and the creatine kinase reaction forward rate constant (kf ) in subjects with bipolar disorder (BD).

Methods: Subjects with bipolar euthymia (n = 14) or depression (n = 11) were recruited. Healthy comparison subjects (HC) (n = 23) were recruited and matched to subjects with BD on age, gender, and educational level.

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Objective: Depression among methamphetamine users is more prevalent in females than males, but gender-specific treatment options for this comorbidity have not been described. Reduced brain phosphocreatine levels have been shown to be lower in female methamphetamine users compared to males, and, of relevance, studies have demonstrated an association between treatment-resistant depression and reduced brain phosphocreatine concentrations. The nutritional supplement creatine monohydrate has been reported to reduce symptoms of depression in female adolescents and adults taking antidepressants, as well as to increase brain phosphocreatine in healthy volunteers.

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Background: A high prevalence of tobacco smoking has been observed in methamphetamine users, but there have been no in vivo brain neurochemistry studies addressing gender effects of tobacco smoking in methamphetamine users. Methamphetamine addiction is associated with increased risk of depression and anxiety in females. There is increasing evidence that selective analogues of nicotine, a principal active component of tobacco smoking, may ease depression and improve cognitive performance in animals and humans.

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Background: Delayed diagnosis in bipolar disorder (BD) due to misdiagnosis as major depressive disorder (MDD) is a significant public health concern. Thus, identification of relevant diagnostic biomarkers is a critical unmet need, particularly early in the course of illness. The anterior cingulate cortex (ACC) is thought to play an important role in mood disorder pathophysiology.

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Normal brain activity is associated with task-related pH changes. Although central nervous system syndromes associated with significant acidosis and alkalosis are well understood, the effects of less dramatic and chronic changes in brain pH are uncertain. One environmental factor known to alter brain pH is the extreme, acute change in altitude encountered by mountaineers.

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Introduction: The potential neurochemical toxicity associated with methamphetamine (MA) or marijuana (MJ) use on the developing adolescent brain is unclear, particularly with regard to individuals with concomitant use of MA and MJ (MA+MJ). In this study, proton magnetic resonance spectroscopy (MRS) was utilized to measure in vivo brain N-acetylaspartate plus N-acetylaspartyl glutamate (tNAA, an indicator of intact neuronal integrity) levels.

Methods: Three adolescent groups from Cape Town, South Africa completed MRS scans as well as clinical measures including a drug use history.

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Tissue water transverse relaxation times (T2) are highly sensitive to fluid and lipid accumulations in skeletal muscles whereas the related T2* is sensitive to changes in tissue oxygenation in addition to factors affecting T2. Diabetes mellitus (DM) affects muscles of lower extremities progressively by impairing blood flow at the macrovascular and microvascular levels. This study is to investigate whether T2 and T2* are sensitive enough to detect abnormalities in skeletal muscles of diabetic patients in the resting state.

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Background: Mitochondria-related mechanisms have been suggested to mediate methamphetamine (METH) toxicity. However, changes in brain energetics associated with high-energy phosphate metabolism have not been investigated in METH users. Phosphorus-31 ((31)P) magnetic resonance spectroscopy (MRS) was used to evaluate changes in mitochondrial high energy phosphates, including phosphocreatine (PCr) and β-nucleoside triphosphate (β-NTP, primarily ATP in brain) levels.

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Objectives: To compare the concentrations of high-energy phosphorus metabolites associated with mitochondrial function in the frontal lobe of depressed adolescents with bipolar disorder (BD) and healthy controls (HC).

Methods: We used in vivo phosphorus-31 magnetic resonance spectroscopy ((31) P-MRS) at 3 Tesla to measure phosphocreatine (PCr), beta-nucleoside triphosphate (β-NTP), inorganic phosphate (Pi), and other neurometabolites in the frontal lobe of eight unmedicated and six medicated adolescents with bipolar depression and 24 adolescent HCs.

Results: Analysis of covariance, including age as a covariate, revealed differences in PCr (p=0.

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High-energy phosphate metabolism, which allows the synthesis and regeneration of adenosine triphosphate (ATP), is a vital process for neuronal survival and activity. In particular, creatine kinase (CK) serves as an energy reservoir for the rapid buffering of ATP levels. Altered CK enzyme activity, reflecting compromised high-energy phosphate metabolism or mitochondrial dysfunction in the brain, can be assessed using magnetization transfer (MT) MRS.

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Background: Adolescent major depressive disorder (MDD) is a life-threatening brain disease with limited interventions. Treatment resistance is common, and the illness burden is disproportionately borne by females. 31-Phosphorus magnetic resonance spectroscopy ((31)P MRS) is a translational method for in vivo measurement of brain energy metabolites.

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