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Although the cardiovascular benefits of an increased urinary potassium excretion have been suggested, little is known about the potential cardiac association of urinary potassium excretion in patients with chronic kidney disease (CKD). In addition, whether the cardiac association of urinary potassium excretion was mediated by serum potassium levels has not been studied yet. We reviewed the data of 1,633 patients from a large-scale multicenter prospective Korean study (2011–2016). Spot urinary potassium to creatinine ratio was used as a surrogate for urinary potassium excretion. Cardiac injury was defined as a highly sensitive troponin T (hs-TnT) ≥ 14 ng/L. Odds ratios (ORs) and 95% confidence intervals (CIs) for cardiac injury were calculated using logistic regression analyses. Of 1,633 patients, the mean spot urinary potassium to creatinine ratio was 49.5 ± 22.6 mmol/g Cr and the overall prevalence of cardiac injury was 33.9%. Although serum potassium levels were not associated with cardiac injury, per 10 mmol/g Cr increase in the spot urinary potassium to creatinine ratio was associated with decreased odds of cardiac injury: OR (95% CI) of 0.917 95% CI (0.841-0.998, P= 0.047) in multivariate logistic regression analysis. In mediation analysis, approximately 6.4% of the relationship between spot urinary potassium to creatinine ratio and cardiac injury was mediated by serum potassium levels, which was not statistically significant (P = 0.368). Higher urinary potassium excretion was associated with lower odds of cardiac injury, which was not mediated by serum potassium levels.
Radiocarbon (14C) in natural samples undergoes changes due to variations in atmospheric CO2 resulting from anthropogenic activities. To analyze the variation of the 14C ratio in atmospheric CO2, deciduous tree leaves were collected in Gyeongju, a popular tourist city in South Korea. Leaf samples were collected from Prunus subg. Cerasus trees at five different sampling points throughout the city over 3 years (2018, 2020, and 2021). The 14C data of the samples were categorized into three groups (downtown, rural, and tourist sites) and analyzed for variations among the different years. The 14C ratio at downtown sites was stable after 2018, the rural site ratio increased between 2018 and 2020 and then decreased between 2020 and 2021, and the tourist site ratio increased after 2018. We theorize that the increased 14C ratio at the tourist site was caused by a decrease in tourism after 2018.
We investigated the change in limbic structure volumes and intrinsic limbic network in patients with obstructive sleep apnea (OSA) compared to healthy controls.
We enrolled 26 patients with OSA and 30 healthy controls. They underwent three-dimensional T1-weighted magnetic resonance imaging (MRI) on a 3 T MRI scanner. The limbic structures were analyzed volumetrically using the FreeSurfer program. We examined the intrinsic limbic network using the Brain Analysis with Graph Theory program and compared the groups' limbic structure volumes and intrinsic limbic network.
There were significant differences in specific limbic structure volumes between the groups. The volumes in the right amygdala, right hippocampus, right hypothalamus, right nucleus accumbens, left amygdala, left basal forebrain, left hippocampus, left hypothalamus, and left nucleus accumbens in patients with OSA were lower than those in healthy controls (right amygdala, 0.102 vs. 0.113%, p = 0.004; right hippocampus, 0.253 vs. 0.281%, p = 0.002; right hypothalamus, 0.028 vs. 0.032%, p = 0.002; right nucleus accumbens, 0.021 vs. 0.024%, p = 0.019; left amygdala, 0.089 vs. 0.098%, p = 0.007; left basal forebrain, 0.020 vs. 0.022%, p = 0.027; left hippocampus, 0.245 vs. 0.265%, p = 0.021; left hypothalamus, 0.028 vs. 0.031%, p = 0.016; left nucleus accumbens, 0.023 vs. 0.027%, p = 0.002). However, there were no significant differences in network measures between the groups.
We demonstrate that the volumes of several limbic structures in patients with OSA are significantly lower than those in healthy controls. However, there are no alterations to the intrinsic limbic network. These findings suggest that OSA is one of the risk factors for cognitive impairments.
Mood disorders require consistent management of symptoms to prevent recurrences of mood episodes. Circadian rhythm (CR) disruption is a key symptom of mood disorders to be proactively managed to prevent mood episode recurrences. This study aims to predict impending mood episodes recurrences using digital phenotypes related to CR obtained from wearable devices and smartphones.
The study is a multicenter, nationwide, prospective, observational study with major depressive disorder, bipolar disorder I, and bipolar II disorder. A total of 495 patients were recruited from eight hospitals in South Korea. Patients were followed up for an average of 279.7 days (a total sample of 75 506 days) with wearable devices and smartphones and with clinical interviews conducted every 3 months. Algorithms predicting impending mood episodes were developed with machine learning. Algorithm-predicted mood episodes were then compared to those identified through face-to-face clinical interviews incorporating ecological momentary assessments of daily mood and energy.
Two hundred seventy mood episodes recurred in 135 subjects during the follow-up period. The prediction accuracies for impending major depressive episodes, manic episodes, and hypomanic episodes for the next 3 days were 90.1, 92.6, and 93.0%, with the area under the curve values of 0.937, 0.957, and 0.963, respectively.
We predicted the onset of mood episode recurrences exclusively using digital phenotypes. Specifically, phenotypes indicating CR misalignment contributed the most to the prediction of episodes recurrences. Our findings suggest that monitoring of CR using digital devices can be useful in preventing and treating mood disorders.
Severe heat exposure causes mitochondrial fragmentation and dysfunction, which contribute to the pathogenesis of heat-related illness. l-Citrulline is a naturally occurring amino acid and has been suggested to influence heat shock responses. This study aimed to test whether l-citrulline supplementation would preserve mitochondrial integrity and attenuate heat-induced skeletal muscle injury and elucidate the underlying mechanisms. At 37°C, l-citrulline (2 mM) increased mitochondrial elongation in mouse C2C12 myoblasts, a process associated with a reduction in mitochondrial fission protein Drp1 levels. Mechanistic studies revealed that l-citrulline increased cellular nitric oxide (NO) levels, but not S-nitrosylation of Drp1. l-Citrulline caused a decrease in phosphorylation of Drp1 at Ser 616 and an increase in phosphorylation of Drp1 at Ser 637, which resulted in a reduced mitochondrial localisation of Drp1. L-NAME, a non-selective NO synthase inhibitor, abolished the increase in l-citrulline-induced NO levels and inhibited Drp1 phosphorylation changes and mitochondrial elongation, which indicates the involvement of a NO-dependent pathway. Under 43°C heat stress conditions, l-citrulline prevented translocation of Drp1 to mitochondria, mitochondrial fragmentation and decreased membrane potential. Finally, l-citrulline pretreatment inhibited heat-induced reactive oxygen species overproduction, caspase 3/7 activation, apoptotic cell death and improved cell viability. NO inhibitor l-NAME abolished all the above protective effects of l-citrulline under heat stress. Our results suggest that l-citrulline prevents heat-induced mitochondrial dysfunction and cell injury through NO-mediated Drp1 inhibition in C2C12 myoblasts. l-Citrulline may be an effective treatment for heat-related illnesses and other mitochondrial diseases.
To explore sea level transgression in low-lying inland areas and its possible influence on prehistoric cultures, we investigated the physical and geochemical features of 20-m-long sedimentary cores from the previously seawater-filled Daesan Basin located in the middle reach of the present Nakdong River in Korea as proxies for seawater transgression deep inland areas due to Holocene sea level rise. Based on the relationships among grain size, total sulfur content (TS%), and carbon/sulfur (C/S) ratio, the first transgressive event was detected at ca. 8500 cal yr BP, caused by seawater influx along the present Nakdong River. Higher TS% (0.8–1%) and interbedded fossil oysters at 8000–6000 cal yr BP indicate marine environments, supporting a paleo-Daesan Bay with water depth of ~10–8 m. The common peaks in TS%, in both inland paleo-Daesan Bay and a present coastal area (Suncheon Bay) in southern Korea (e.g., at 3200 and 4700 cal yr BP), may indicate intervals of higher salinity, which suggests simultaneous responses to changes in sea level or hydroclimate. The duration of marine environment (paleo-Daesan Bay) in the remote inland from ca. 8000–3200 cal yr BP provides an analog for inland paleo-bay studies in East Asia.
Nosocomial transmission of COVID-19 among immunocompromised hosts can have a serious impact on COVID-19 severity, underlying disease progression and SARS-CoV-2 transmission to other patients and healthcare workers within hospitals. We experienced a nosocomial outbreak of COVID-19 in the setting of a daycare unit for paediatric and young adult cancer patients. Between 9 and 18 November 2020, 473 individuals (181 patients, 247 caregivers/siblings and 45 staff members) were exposed to the index case, who was a nursing staff. Among them, three patients and four caregivers were infected. Two 5-year-old cancer patients with COVID-19 were not severely ill, but a 25-year-old cancer patient showed prolonged shedding of SARS-CoV-2 RNA for at least 12 weeks, which probably infected his mother at home approximately 7–8 weeks after the initial diagnosis. Except for this case, no secondary transmission was observed from the confirmed cases in either the hospital or the community. To conclude, in the day care setting of immunocompromised children and young adults, the rate of in-hospital transmission of SARS-CoV-2 was 1.6% when applying the stringent policy of infection prevention and control, including universal mask application and rapid and extensive contact investigation. Severely immunocompromised children/young adults with COVID-19 would have to be carefully managed after the mandatory isolation period while keeping the possibility of prolonged shedding of live virus in mind.
Mental illness among survivors of coronavirus disease 2019 (COVID-2019) during the post-illness period is an emerging and important health issue.
We aimed to investigate the prevalence of mental illness and the associated factors for its development among COVID-2019 survivors.
From 1 January to 4 June 2020, data were extracted from the National Health Insurance Service COVID-19 database in South Korea. Patients with COVID-19 were defined as those whose test results indicated that they had contracted the infection, regardless of disease severity. COVID-19 survivors were defined as those who recovered from the infection. The primary end-point was the development of mental illness, which was evaluated between 1 January and 1 December 2020.
A total 260 883 individuals were included in this study, and 2.36% (6148) were COVID-19 survivors. The COVID-19 survivors showed higher prevalence of mental illness than the control group (12.0% in the COVID-19 survivors v. 7.7% in the control group; odds ratio (OR) = 2.40, 95% CI 2.21–2.61, P < 0.001). Additionally, compared with the control group, the no specific treatment for COVID-19 group (OR = 2.23, 95% CI 2.03–2.45, P < 0.001) and specific treatment for COVID-19 group (OR = 3.27, 95% CI 2.77–3.87, P < 0.001) showed higher prevalence of mental illness among survivors.
In South Korea, COVID-19 survivors had a higher risk of developing mental illness compared with the rest of the populations. Moreover, this trend was more evident in COVID-19 survivors who experienced specific treatment in the hospital.
We examine the physical conditions required for the formation of H2 in the solar neighborhood by comparing H i emission and absorption spectra toward 58 lines of sight at b < −5∘ to CO(1–0) and dust data. Our analysis of CO-associated cold and warm neutral medium (CNM and WNM) shows that the formation of CO-traced molecular gas is favored in regions with high column densities where the CNM becomes colder and more abundant. In addition, our comparison to the one-dimensional steady-state H i-to-H2 transition model of Bialy et al. (2016) suggests that only a small fraction of the clumpy CNM participates in the formation of CO-traced molecular gas. Another possible interpretation would be that missing physical and chemical processes in the model could play an important role in H2 formation.
Atomically sharpened tips have attracted much interest in the imaging and manufacturing fields due to their high spatial resolutions. Typically, tungsten (W) is mainly used as the material of such a tip, but when the W tip is used in an oxygen environment, a limit is revealed due to corrosiveness stemming from a reaction with the oxygen gas. To solve this problem, methods of depositing a metal on W that does not react with oxygen have been studied. In this study, we introduce a method of depositing iridium (Ir) directly onto an insulating layer without an additional pretreatment to remove the insulating layer remaining on the W surface, forming an Ir-nanopyramid structure at the apex of the W tip by field evaporation and faceting. Field ion microscopy and atom probe tomography were used to analyze the crystal structure and composition at the apex during the faceting process, and the overall tip shape change after faceting was compared and analyzed with transmission electron microscopy. The proposed method does not have a tip heating step when creating an atomically sharp tip such that it can be made easily with a simpler equipment configuration than in the existing method.
We aim to determine the association between Fe status and the metabolic syndrome (MetS) during menopause. Records of 1069 premenopausal and 703 postmenopausal Korean women were retrieved from the database of the fifth Korean National Health and Nutrition Examination Survey (KNHANES V 2012) and analysed. The association between the MetS and Fe status was performed using multivariable-adjusted analyses, subsequently develop a prediction model for the MetS by margin effects. We found that the risk of Fe depletion among postmenopausal women was lower than premenopausal women (PR = 0·813, 95 % CI 0·668, 0·998, P = 0·038). The risk of the MetS was 2·562-fold lower among premenopausal women with than without Fe depletion (PR = 0·390, 95 % CI 0·266, 0·571, P < 0·001). In contrast, the risk of the MetS tended to be higher among postmenopausal women with than without Fe depletion (PR = 1·849, 95 % CI 1·406, 2·432, P < 0·001). When the serum ferritin levels increased, the risk of the MetS increased in both premenopausal women and postmenopausal women. The margin effects showed that an increase in serum Hb and ferritin was associated with an increase in the risk of the MetS according to menopausal status and age group. Therefore, ferritin is the most validated and widely used Fe marker, could be a potential clinical value in predicting and monitoring the MetS during menopause. Further prospective or longitudinal studies, especially, clinically related studies on menopause and Fe status, are needed to clarify the causality between serum ferritin levels and the MetS that could offer novel treatments for the MetS.
This article reviews the advancements and prospects of liquid cell transmission electron microscopy (TEM) imaging and analysis methods in understanding the nucleation, growth, etching, and assembly dynamics of nanocrystals. The bonding of atoms into nanoscale crystallites produces materials with nonadditive properties unique to their size and geometry. The recent application of in situ liquid cell TEM to nanocrystal development has initiated a paradigm shift, (1) from trial-and-error synthesis to a mechanistic understanding of the “synthetic reactions” responsible for the emergence of crystallites from a disordered soup of reactive species (e.g., ions, atoms, molecules) and shape-defined growth or etching; and (2) from post-processing characterization of the nanocrystals’ superlattice assemblies to in situ imaging and mapping of the fundamental interactions and energy landscape governing their collective phase behaviors. Imaging nanocrystal formation and assembly processes on the single-particle level in solution immediately impacts many existing fields, including materials science, nanochemistry, colloidal science, biology, environmental science, electrochemistry, mineralization, soft condensed-matter physics, and device fabrication.
The study aims to examine whether cognitive deficits are different between patients with early stage Alzheimer's disease (AD) and patients with early stage vascular dementia (VaD) using the Korean version of the CERAD neuropsychological battery (CERAD-K-N).
Patients with early stage dementia, global Clinical Dementia Rating (CDR) 0.5 or 1 were consecutively recruited among first visitors to a dementia clinic, 257 AD patients and 90 VaD patients completed the protocol of the Korean version of the CERAD clinical assessment battery. CERAD-K-N was administered for the comprehensive evaluation of the neuropsychological function.
Of the total 347 participants, 257 (69.1%) were AD group (CDR 0.5 = 66.9%) and 90 (21.9%) were VaD group (CDR 0.5 = 40.0%). Patients with very mild AD showed poorer performances in Boston naming test (BNT) (P = 0.028), word list memory test (P < 0.001), word list recall test (P < 0.001) and word list recognition test (WLRcT) (P = 0.006) than very mild VaD after adjustment of T score of MMSE-KC. However, the performance of trail making A (TMA) was more impaired in VaD group than in AD group. The performance of WLRcT (P < 0.001) was the worst among neuropsychological tests within AD group, whereas TMA was performed worst within VaD group.
Patients with early-stage AD have more cognitive deficits on memory and language while patients with early-stage VaD show worse cognitive function on attention/processing speed. In addition, as the first cognitive deficit, memory dysfunction comes in AD and deficit in attention/processing speed in VaD.
Disclosure of interest
The authors have not supplied their declaration of competing interest.
This research examined gender variations in depressive mood for high school students affected by emotional upset and how such depressive mood affect their sleep quality.
Research was conducted from September 2015 to October 2015. Both males and females were divided into normal group and depressive group by Zung Self-rating Depression Scale (ZSDS). Each group adopted the Pittsburgh Sleep Quality Index (PSQI) to measure sleep quality.
Analysis was made on a total of 155 students, which were 83 male students and 72 female. The average ZSDS for all high school students was 43.38 and the average PSQI was 5.39. The number of male students in the normal and depressive group who were diagnosed with sleep disorder were 2 (3.8%) and 9 (29.0%), respectively (P < 0.05). But the number of female students in the normal and depressive group who were diagnosed with sleep disorder were 11 (32.4%) and 33 (86.8%), respectively (P < 0.05). Both males and females shared a meaningful result over sleep latency, sleep disturbance, use of sleep medication, and daytime functional disturbance among 7 items of PSQI for sleep quality, and female students had a significantly meaningful result over sleep duration, habitual sleep effects (P < 0.05).
This research showed that sleep quality of all high school students was not too bad but it can be problematic for those with depressive mood. Especially, female students were diagnosed with sleep disorder more than male students.
Disclosure of interest
The authors have not supplied their declaration of competing interest.
The international guideline for treating depression has been widely used.
The current study focused on the maintenance treatment section of the third revision of Korean Medication Algorithm for Depressive Disorder (KMAP-DD)
A 44-item questionnaire was used to obtain the consensus of experts regarding pharmacological treatment strategies for depressive disorder. Of the 144 committee members, 79 psychiatrists responded to the survey. Each treatment strategy or treatment option was evaluated with the nine-point scale.
Most clinicians answered to maintain both antidepressants (AD) and atypical antipsychotics (AAP) for psychotic depression in remission state. The duration of AD maintenance: from 19.8 weeks to 46.8 weeks for patients in remission of the first episode, from 34.8 weeks to 78.4 weeks for the second depressive episode, and long-term continuation for three or more depressive episodes. Aripiprazole was the most preferred AAP. The preferred doses of AD and AAP in maintenance treatment were about 75% and 50% of those in acute treatment The maintenance of AAP in the psychotic depression in remission was similar to the AD, although shorter and less.
The maintenance strategies of KMAP-DD 2017 were similar to those of KMAP-DD 2012. Most clinicians preferred to maintain AD for substantial duration after achieving remission. The maintenance of AAP was also preferred, but the duration was shorter than AD.
Disclosure of interest
The authors have not supplied their declaration of competing interest.
The experiments reported in this research paper aimed to determine the effect of supplementing different forms of L-methionine (L-Met) and acetate on protein synthesis in immortalized bovine mammary epithelial cell line (MAC-T cells). Treatments were Control, L-Met, conjugated L-Met and acetate (CMA), and non-conjugated L-Met and Acetate (NMA). Protein synthesis mechanism was determined by omics method. NMA group had the highest protein content in the media and CSN2 mRNA expression levels (P < 0.05). The number of upregulated and downregulated proteins observed were 39 and 77 in L-Met group, 62 and 80 in CMA group and 50 and 81 in NMA group from 448 proteins, respectively (P < 0.05). L-Met, NMA and CMA treatments stimulated pathways related to protein and energy metabolism (P < 0.05). Metabolomic analysis also revealed that L-Met, CMA and NMA treatments resulted in increases of several metabolites (P < 0.05). In conclusion, NMA treatment increased protein concentration and expression level of CSN2 mRNA in MAC-T cells compared to control as well as L-Met and CMA treatments through increased expression of milk protein synthesis-related genes and production of the proteins and metabolites involved in energy and protein synthesis pathways.
Serotonergic dysfunction may play an important role in motor and nonmotor symptoms of Parkinson’s disease (PD). The loudness dependence of auditory evoked potentials (LDAEP) has been used to evaluate serotonergic activity. Therefore, this study aimed to determine central serotonergic activity using LDAEP in de novo PD according to the age at onset and changes in serotonergic activity after dopaminergic treatment.
A total of 30 patients with unmedicated PD, 16 in the early-onset and 14 in the late-onset groups, were enrolled. All subjects underwent comprehensive neurological examination, laboratory tests, the Unified Parkinson’s Disease Rating Scale, and LDAEP. The LDAEP was calculated as the slope of the two N1/P2 peaks measured at the Cz electrode, first at baseline conditions (pretreatment) and a second time after 12 weeks (post-treatment) following dopaminergic medications.
The absolute values of pretreatment N1/P2 LDAEP (early-onset: late-onset, 0.99 ± 0.68: 1.62 ± 0.88, p = 0.035) and post-treatment N1 LDAEP (early-onset: late-onset, −0.61 ± 0.61: −1.26 ± 0.91, p = 0.03) were significantly lower in the early-onset group compared with those of the late-onset group. In addition, a higher value of pretreatment N1/P2 LDAEP was significantly correlated with the late-onset group (coefficient = 1.204, p = 0.044). The absolute value of the N1 LDAEP decreased after 12 weeks of taking dopaminergic medication (pretreatment: post-treatment, −1.457 ± 1.078: −0.904 ± 0.812, p = 0.0018).
Based on the results of this study, LDAEP could be a marker for serotonergic neurotransmission in PD. Central serotonergic activity assessed by LDAEP may be more preserved in early-onset PD patients and can be altered with dopaminergic medication.