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"Lim, Hyun"
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Mortality and causes of death in patients with atrial fibrillation: A nationwide population-based study
Patients with atrial fibrillation are known to have a high risk of mortality. There is a paucity of population-based studies about the impact of atrial fibrillation on the mortality risk stratified by age, sex, and detailed causes of death.
A total of 15,411 patients with atrial fibrillation from the Korean National Health Insurance Service-National Sample Cohort were enrolled, and causes of death were identified according to codes of the 10th revision of the International Classification of Diseases.
From 2002 to 2013, a total of 4,479 (29%) deaths were confirmed, and the crude mortality rate for all-cause death was 63.3 per 1,000 patient-years. Patients with atrial fibrillation had a 3.7-fold increased risk of all-cause death compared with the general population. The standardized mortality ratio for all-cause death was the highest in young patients and decreased with increasing age (standardized mortality ratio 21.93, 95% confidence interval 7.60-26.26 in patients aged <20 years; standardized mortality ratio 2.77, 95% confidence interval 2.63-2.91 in patients aged ≥80 years). Women with atrial fibrillation exhibited a greater excess mortality risk than men (standardized mortality ratio 3.81, 95% confidence interval 3.65-3.98 in women; standardized mortality ratio 3.35, 95% confidence interval 3.21-3.48 in men). Cardiovascular disease was the leading cause of death (38.5%), and cerebral infarction was the most common specific disease. Patients with atrial fibrillation had an about 5 times increased risk of death due to cardiovascular disease compared with the general population.
Patients with atrial fibrillation had a 4 times increased risk of mortality compared with the general population. However, the impact of atrial fibrillation on mortality decreased with age and in men. Cerebral infarction was the most common cause of death, and more attention should be paid to reducing the risk of stroke.
Journal Article
Subclinical alterations in left ventricular structure and function according to obesity and metabolic health status
Obesity and metabolic syndrome (MetS) are associated with high risk of cardiac dysfunction and heart failure. We assessed the effect of obesity and metabolic health status on left ventricular (LV) structure and function in subjects without overt heart disease.
In 789 subjects (58.8±13.0 years, 50.7% males) without overt heart disease, LV morphology and function were compared among 6 groups stratified by body mass index (BMI) (normal weight, overweight and obese) and metabolic health status (meeting ≤1 criterion of MetS excluding waist circumference defined as metabolically healthy; otherwise, metabolically unhealthy).
LV ejection fraction (LVEF) was not different among the 6 groups (P>0.05). However, high BMI and poor metabolic health were associated with poorer global longitudinal strain (GLS), higher LV mass index (LVMI) and higher E/e' (P<0.001). Poor metabolic health status was associated with greater adverse changes in LV structure and function than obesity, and among MetS components, high systolic blood pressure (SBP) showed the greatest impact. Higher SBP, BMI and triglycerides were independently associated with worse GLS, and higher SBP was also associated with worse LVMI and E/e´. GLS, LVMI and E/e´ worsened in proportion to the number of MetS criteria or continuous MetS scores. Adverse myocardial changes associated with obesity were significant in the metabolically healthy group, but not in the metabolically unhealthy group.
Obesity and poor metabolic health status were associated with subclinical decrement in LV systolic and diastolic function, and higher LV mass, but not with LVEF, in subjects without overt heart disease.
Journal Article
Mass dictatorship and memory as ever present past
\"The landscape of memory studies has been transformed by a growing consciousness of global interconnectedness and the politics of human rights. The essays in this volume of the Mass Dictatorship project explore the entangled pasts of dictatorships, the tensions between de-territorializing and re-territorializing memories, and the competitive construction of memories of the intersubjective past from a world-wide perspective. Written from a variety of differing historical perspectives, cultural positions, and disciplinary backgrounds, the collection searches for historical accountability across the generations of the post-war era\"--Publisher's website.
Book
Selective PPARδ Agonist GW501516 Protects Against LPS-Induced Macrophage Inflammation and Acute Liver Failure in Mice via Suppressing Inflammatory Mediators
Inflammation is critical in the development of acute liver failure (ALF). Peroxisome proliferator-activated receptor delta (PPARδ) regulates anti-inflammatory responses and is protective in several diseases such as obesity and cancer. However, the beneficial effects and underlying mechanisms of PPARδ agonist GW501516 in ALF remain unclear. This study investigated the molecular mechanisms underlying the anti-inflammatory effects of GW501516 in macrophages and assessed its protective potential against lipopolysaccharide (LPS)/galactosamine (GalN)-induced ALF. In vivo administration of GW501516 significantly reduced LPS/GalN-induced hepatotoxicity, as evidenced by lower mortality, decreased liver damage, and attenuated secretion of IL-1β, IL-6, and TNF-α. GW501516 treatment also decreased LPS-induced nitric oxide synthase 2 (NOS2) expression and nitric oxide (NO) production in RAW264.7 cells, an effect reversed by PPARδ siRNA. Additionally, GW501516 inhibited LPS-induced phosphorylation of p38 and c-Jun N-terminal kinase (JNK), suggesting that inactivation of these MAPKs contributes to its effects. The secretion of IL-6, TNF-α, and NF-κB DNA-binding activity were also suppressed by GW501516, while the nuclear translocation of the NF-κB p65 subunit was unaffected. In conclusion, our findings suggest that GW501516 exerts protective effects in ALF by inhibiting the production of inflammatory mediators. Therefore, GW501516 may act as a potential agent for developing anti-inflammatory therapies for ALF.
Journal Article
The prevalence of psychiatric comorbidities in adult ADHD compared with non-ADHD populations: A systematic literature review
Comorbid psychiatric disorders in adults with ADHD are important because these comorbidities might complicate the diagnosis of ADHD and also worsen the prognosis. However, the prevalence of comorbid psychiatric disorders in adult ADHD varies according to the diagnostic tools used and the characteristics of target populations. The purpose of this review was to describe the prevalence of comorbid psychiatric disorders in adults with ADHD compared with adults without ADHD. Thirty-two studies published before August 2022 were identified and classified according to diagnosis of other psychiatric disorder in those with ADHD. The most frequent comorbid psychiatric disorder in the ADHD group was substance use disorder (SUD), followed by mood disorders, anxiety disorders, and personality disorders. The prevalence of these four disorders was higher in the ADHD group, whether or not subjects were diagnosed with other psychiatric disorders. In addition, the diversity of ADHD diagnostic tools was observed. This also might have affected the variability in prevalence of comorbidities. Standardization of ADHD diagnostic tools is necessary in the future.
Journal Article
2021 Korean Thyroid Imaging Reporting and Data System and Imaging-Based Management of Thyroid Nodules: Korean Society of Thyroid Radiology Consensus Statement and Recommendations
Incidental thyroid nodules are commonly detected on ultrasonography (US). This has contributed to the rapidly rising incidence of low-risk papillary thyroid carcinoma over the last 20 years. The appropriate diagnosis and management of these patients is based on the risk factors related to the patients as well as the thyroid nodules. The Korean Society of Thyroid Radiology (KSThR) published consensus recommendations for US-based management of thyroid nodules in 2011 and revised them in 2016. These guidelines have been used as the standard guidelines in Korea. However, recent advances in the diagnosis and management of thyroid nodules have necessitated the revision of the original recommendations. The task force of the KSThR has revised the Korean Thyroid Imaging Reporting and Data System and recommendations for US lexicon, biopsy criteria, US criteria of extrathyroidal extension, optimal thyroid computed tomography protocol, and US follow-up of thyroid nodules before and after biopsy. The biopsy criteria were revised to reduce unnecessary biopsies for benign nodules while maintaining an appropriate sensitivity for the detection of malignant tumors in small (1-2 cm) thyroid nodules. The goal of these recommendations is to provide the optimal scientific evidence and expert opinion consensus regarding US-based diagnosis and management of thyroid nodules.
Journal Article
Randomized, Double-blind, Placebo-controlled Study of a Multispecies Probiotic Mixture in Nonalcoholic Fatty Liver Disease
The intestinal microbiota is closely associated with the development of obesity and nonalcoholic fatty liver disease (NAFLD). This study investigated the effects of probiotic treatment on visceral fat area (VFA) and intrahepatic fat (IHF) fraction in NAFLD. Sixty-eight obese NAFLD patients (>5% proton density fat fraction [PDFF] on magnetic resonance imaging [MRI]) were randomized to probiotic and placebo groups for 12 weeks. The probiotic mixture included 6 bacterial species. VFA and IHF were measured using the MRI-PDFF technique. Body weight and total body fat were reduced in the probiotic group but not in the placebo group. The mean IHF fraction was reduced after 12 weeks of treatment in the probiotic group compared to that at baseline (from 16.3 ± 15.0% to 14.1 ± 7.7%, p = 0.032) but was not reduced in the placebo group. The decrease in IHF (mean difference: −2.61%, p = 0.012) was also greater in the probiotic group than in the placebo group. Reduction of triglyceride was greater in the probiotic treatment group than in the placebo group (mean difference: −34.0 mg/dl, p = 0.0033). However, the changes in IHF percentage and triglyceride levels were not different between placebo and control groups after adjusting for changes in body weight. Treatment with probiotics for 12 weeks resulted in significant reduction in IHF and body weight in obese NAFLD patients.
Journal Article
Federated Reinforcement Learning for Training Control Policies on Multiple IoT Devices
Reinforcement learning has recently been studied in various fields and also used to optimally control IoT devices supporting the expansion of Internet connection beyond the usual standard devices. In this paper, we try to allow multiple reinforcement learning agents to learn optimal control policy on their own IoT devices of the same type but with slightly different dynamics. For such multiple IoT devices, there is no guarantee that an agent who interacts only with one IoT device and learns the optimal control policy will also control another IoT device well. Therefore, we may need to apply independent reinforcement learning to each IoT device individually, which requires a costly or time-consuming effort. To solve this problem, we propose a new federated reinforcement learning architecture where each agent working on its independent IoT device shares their learning experience (i.e., the gradient of loss function) with each other, and transfers a mature policy model parameters into other agents. They accelerate its learning process by using mature parameters. We incorporate the actor–critic proximal policy optimization (Actor–Critic PPO) algorithm into each agent in the proposed collaborative architecture and propose an efficient procedure for the gradient sharing and the model transfer. Using multiple rotary inverted pendulum devices interconnected via a network switch, we demonstrate that the proposed federated reinforcement learning scheme can effectively facilitate the learning process for multiple IoT devices and that the learning speed can be faster if more agents are involved.
Journal Article