Brain structural correlates of subjective sleepiness and insomnia symptoms in shift workers.

Background: Studies on the brain structures of shift workers are limited; thus, this cross-sectional study aimed to compare the brain structures and the brain structural correlates of subjective sleepiness and insomnia symptoms between shift workers and non-shift workers. Methods: Shift workers (n = 63) and non-shift workers (n = 58) completed questionnaires assessing subjective sleepiness and insomnia symptoms. Cortical thickness, cortical surface area, and subcortical volumes were measured by magnetic resonance imaging. The brain morphometric measures were compared between the groups, and interaction analyses using the brain morphometric measures as the dependent variable were performed to test the interactions between the study group and measures of sleep disturbance (i.e., subjective sleepiness and insomnia symptoms). Results: No differences in cortical thickness, cortical surface area, or subcortical volumes were detected between shift workers and non-shift workers. A single cluster in the left motor cortex showed a significant interaction between the study group and subjective sleepiness in the cortical surface area. The correlation between the left motor cortex surface area and the subjective sleepiness level was negative in shift workers and positive in non-shift workers. Significant interaction between the study group and insomnia symptoms was present for the left/right putamen volumes. The correlation between the left/right putamen volumes and insomnia symptom levels was positive in shift workers and negative in non-shift workers. Conclusion: Left motor cortex surface area and bilateral putamen volumes were unique structural correlates of subjective sleepiness and insomnia symptoms in shift workers, respectively.

Perfectionism, test anxiety, and neuroticism determines high academic performance: a cross-sectional study.

BACKGROUND: Academic performance is an important issue for Korean students. Various psychological factors contribute to academic performance. We aimed to evaluate the psychological factors that affect academic performance integratively. METHODS: A total of 102 academic high achievers and 120 comparison participants were recruited. We evaluated psychological factors (test anxiety, perfectionism, personality traits, resilience, and self-efficacy) and measured academic performance using the College Scholastic Ability Test and the current college grade. We compared psychological factors and academic performance between the academic high achiever and comparison groups. Multiple linear regression was then conducted to identify the significant psychological factors for high academic performance. Further, we used cluster analysis to classify the comparison group by the significant psychological factors and compared them among clusters and academic high achievers to determine the psychological characteristics of academic high achievers. RESULTS: The academic high achiever group showed lower test anxiety (p = .002), less neuroticism (p = .001), higher self-efficacy (p = .028), and less socially prescribed perfectionism (p < .001) than the comparison group. Multiple linear regression results (p = .020) clarified that neuroticism (p = .020), test anxiety level (p = .047), and perfectionism (p = .035) were important factors predicting better academic performance. Academic high achievers had moderate test anxiety and perfectionism levels, with the best performance on the College Scholastic Ability Test. CONCLUSIONS: Neuroticism, test anxiety levels, and perfectionism are important psychological factors for high academic performance. Interventions targeting these factors may help to improve academic accomplishments.

The Factors Affecting Longitudinal Course of Posttraumatic Stress Disorder Symptoms in Sexual Assault Victims.

OBJECTIVE: This study aimed to identify the factors affecting posttraumatic stress disorder (PTSD) symptom remission prospectively through a 1-year follow-up of sexual assault (SA) victims. METHODS: A total 65 female SA victims who visited the crisis intervention center were included. Self-administered questionnaires regarding PTSD symptoms and PTSD related prognostic factors were conducted at both recruitment (T1) and 1 year after recruitment (T2). The multivariate analyses were used to determine the significant predictors of PTSD remission/non-remission state 1 year after SA. RESULTS: In logistic regression analysis, both anxiety and secondary victimization were identified as significant factors explaining the results on PTSD remission/non-remission state at T2 (Beck's Anxiety Inventory [BAI], p=0.003; Secondary Victimization Questionnaire, p=0.024). In a linear mixed analysis, both depression and anxiety were found to be significant variables leading to changes in Posttraumatic Diagnostic Scale for Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition from T1 to T2 (BAI, p<0.001; Center for Epidemiological Studies Depression Scale, p<0.001). CONCLUSION: Depression, anxiety symptoms, and secondary victimization after SA were associated with PTSD symptom non-remission 1 year after SA.

Circadian misalignment alters resting-state functional connectivity of the salience network in rotating shift workers.

STUDY OBJECTIVES: This study compared resting-state functional connectivity (rsFC) of the salience network (SN) between rotating shift workers (RSWs) and controls. Furthermore, we examined whether rsFC of the SN was correlated with sleep, emotion, cognition, and attention. METHODS: The 60 RSWs and 57 controls enrolled in this study completed self-report questionnaires and sleep diaries to assess subjective sleep quality, and polysomnography and actigraphy to evaluate objective sleep and 24-hour rest-activity rhythm parameters. The participants also underwent resting-state functional magnetic resonance imaging and structural T1 scans. We performed a seed-based rsFC analysis of the SN using the anterior cingulate cortex (ACC) and anterior insula (AI) as seed regions. Furthermore, AI and ACC rsFC were compared in RSWs and controls, and we analyzed correlations between rsFC and variables of interest showing significant group differences. RESULTS: Compared with controls, RSWs showed reduced rsFC between the ACC and right insula, and increased rsFC of the ACC with the left occipital lobe and right superior frontal gyrus extending to the supplementary motor area (SFG/SMA). Moreover, RSWs showed reduced rsFC between the right AI and right superior parietal lobule (SPL). Finally, rsFC between the ACC and right AI was correlated with 24-hour rest-activity rhythmicity. CONCLUSIONS: Although RSWs did not show sleep disturbance, emotional distress, cognitive impairment, or attention deficits, alterations of right insula, left occipital lobe, right SFG/SMA, and right SPL rsFC in the SN indicate that impairments in salience detection and top-down attentional control may emerge in shift workers over time.

Amygdala resting-state functional connectivity alterations in patients with chronic insomnia disorder: correlation with electroencephalography beta power during sleep.

STUDY OBJECTIVES: This study investigated alterations in resting-state functional connectivity (RSFC) and hyperarousal biomarkers in patients with chronic insomnia disorder (CID), compared with good sleepers (GS). We also examined the relationships between altered RSFC and hyperarousal biomarkers. METHODS: Fifty patients with CID and 52 GS completed self-reporting questionnaires, and then underwent polysomnography and resting-state functional magnetic resonance imaging. We analyzed RSFC in the amygdala (AMG) and anterior insula (aINS), which are core regions of the salience network that are likely to be involved in hyperarousal. We also analyzed electroencephalography (EEG) relative beta power and heart rate variability (HRV) parameters (e.g. low and high frequency) during sleep. We then tested between-group differences in the RSFC and hyperarousal biomarkers; we examined correlations of RSFC with EEG beta power and HRV. RESULTS: Compared with GS, patients with CID showed more negative RSFC between the right amygdala (R.AMG) and left supramarginal gyrus (L.SMG), but less positive RSFC between the left aINS and bilateral lateral prefrontal cortex. The R.AMG-L.SMG RSFC was negatively correlated with EEG beta power in central regions (C3: r = -0.336, p = 0.012; C4: r = -0.314, p = 0.024). CONCLUSIONS: Decreased RSFC between the R.AMG and L.SMG in patients with insomnia may reflect the difficulty in cortical top-down regulation of the AMG, indicating daytime hyperarousal. Individuals who experience hyperarousal during the daytime may also exhibit cortical hyperarousal during sleep, as indicated by increased EEG beta power.

Measures of Connectivity and Dorsolateral Prefrontal Cortex Volumes and Depressive Symptoms Following Treatment With Selective Serotonin Reuptake Inhibitors in Adolescents.

Importance: Selective serotonin reuptake inhibitors (SSRIs) are considered a first-line pharmacological treatment for adolescent depression with moderate or higher levels of symptom severity. Thus, it is important to understand neurobiological changes related to SSRIs during the course of treatment for adolescents with depression. Objective: To examine neurobiological changes associated with SSRI treatment in adolescents with major depressive disorder (MDD) by measuring longitudinal changes in volume and resting-state functional connectivity (rsFC) in the dorsolateral prefrontal cortex (DLPFC), a core region of cognitive control. Design, Setting, and Participants: This cohort study was conducted with an open-label design. Adolescents with MDD and healthy controls were recruited at the Seoul National University Hospital (Seoul, South Korea). Adolescents with MDD were treated with escitalopram for 8 weeks. Data analysis was conducted between April 2021 and February 2022. Main Outcomes and Measures: Depressive symptoms were assessed using the Children's Depression Rating Scale-Revised. The outcome measure was defined as the change in Children's Depression Rating Scale-Revised scores from week 0 (before treatment) to week 8 (after treatment) or upon termination. Participants completed structural and resting-state functional magnetic resonance imaging (rsfMRI) assessments before (week 0) and after (week 8) SSRI treatment. Repeated measures analysis of variance and liner mixed model analyses were used to examine the longitudinal associations of SSRI treatment with DLPFC volume and rsFC between responders who showed at least a 40% decrease in depressive symptoms and nonresponders who did not. Results: Ninety-five adolescents with MDD and 57 healthy controls were initially recruited. The final analyses of volume included 36 responders (mean [SD] age, 15.0 [1.6] years; 25 girls [69.4%]) and 26 nonresponders (mean [SD] age, 15.3 [1.5] years; 19 girls [73.1%]). Analyses of rsFC included 33 responders (mean [SD] age, 15.2 [1.5] years; 21 girls [63.6%]) and 26 nonresponders (mean [SD] age, 15.3 [1.5] years; 19 girls [73.1%]). The longitudinal associations of SSRI treatment were more evident in responders than in nonresponders. Responders showed significantly increased right DLPFC volume, decreased bilateral DLPFC rsFC with the superior frontal gyri, and decreased left DLPFC rsFC with the ventromedial PFC after treatment compared with before treatment. Furthermore, increased right DLPFC volume was correlated with decreased rsFC between the right DLPFC and superior frontal gyri after SSRI treatment. Conclusions and Relevance: The preliminary results of this cohort study suggest that the DLPFC volumetric and rsFC changes may serve as potential neurobiological treatment markers that are associated with symptom improvement in adolescents with MDD.

Evaluation of machine-assisted irrigation on removal of intracanal biofilm and extrusion of sodium hypochlorite using a three-dimensionally printed root canal model.

PURPOSE: This study aimed to compare the biofilm removal and apical extrusion of sodium hypochlorite (NaOCl) following machine-assisted irrigation using a three-dimensionally (3D) printed dentin-insert model. METHODS: Multispecies biofilms were formed in a 3D-printed curved root canal model with dentin insert. The model was then placed in a container that was filled with 0.2% agarose gel containing 0.1% m-Cresol purple. Root canals were irrigated with 1% NaOCl using syringe irrigation, sonically agitated (EndoActivator or EDDY) or ultrasonically activated (Endosonic Blue) irrigation. Samples were photographed and the color-changed area was measured. Biofilm removal was assessed using colony-forming unit counting, confocal laser scanning microscopic analysis and scanning electron microscopic observations. The data were analyzed using one-way ANOVA, followed by Tukey test (P < 0.05). RESULTS: EDDY and Endosonic Blue demonstrated significantly greater reduction of biofilms compared to other groups. No significant differences were observed in the remaining biofilm volume in syringe irrigation and EndoActivator groups. Furthermore, EDDY and Endosonic Blue presented with numerous exposed dentinal tubules. EDDY showed significantly greater NaOCl extrusion compared to other groups. CONCLUSION: Ultrasonic activation with a small-sized nickel-titanium file irrigation system may be beneficial in intracanal biofilm removal avoiding extrusion of NaOCl beyond the root apex.

Muricauda spongiicola sp. nov., isolated from the sponge Callyspongia elongata.

A novel Gram-stain-negative, thin-rod-shaped, aerobic, non-motile and yellow-pigmented marine bacterium (designated strain 2012CJ35-5T) was isolated from a marine sponge Callyspongia elongata sampled in Jeju-do, Republic of Korea. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain 2012CJ35-5T belonged to the family Flavobacteriaceae, and was most closely related to Muricauda olearia KCCM 90075T (96.3 %), Muricauda alvinocaridis JCM 33425T (95.7 %), Muricauda flava KCTC 22665T (95.6 %), Muricauda koreensis KCTC 52351T (95.6 %) and Muricauda eckloniae KCTC 22266T (94.9 %). Average nucleotide identity, amino acid identities and digital DNA-DNA hybridization between strain 2012CJ35-5T and the closest related strain were 72.6, 73.6 and 17.3 % respectively, indicating that strain 2012CJ35-5T represents a novel species of the genus Muricauda. The genome size of strain 2012CJ35-5T is 3.8 Mbp and the G+C content is 43.9 mol%. Strain 2012CJ35-5T contained menaquinone 6 as the major respiratory quinone and phosphatidylethanolamine, four unidentified aminophospholipids and five unidentified lipids as major polar lipids. The fatty acids were mainly (>15 %) defined as C15 : 0 iso (31.7 %), C15 : 1 iso G (29.2 %) and C17 : 0 iso 3OH (18.0 %). Strain 2012CJ35-5T could be distinguished from the other members of the genus Muricauda by a number of chemotaxonomic and phenotypic characteristics. Based on the results of polyphasic taxonomic analysis, strain 2012CJ35-5T (=KACC 22643T=LMG 32584T) represents a novel species within the genus Muricauda, for which the name Muricauda spongiicola sp. nov. is proposed.

Erratum: A Study of the Reliability and Validity of the Korean Version of DSM-5 Symptom Measure-Inattention and Anger for Parent and Guardian of Child Age 6 to 17.

[This corrects the article on p. 71 in vol. 32, PMID: 33828406.].

Psychological Aspects of Child Maltreatment.

In this review, we provide information about the etiology, risk factors, and clinical presentations of maltreatment to help clinicians better understand child abuse and neglect. Child maltreatment is a major global health challenge that can result in severe consequences. Abused and neglected children are likely to develop psychiatric disorders, such as major depressive disorder, anxiety disorder, and posttraumatic stress disorder. Understanding child maltreatment is expected to prevent and reduce victimization in children, adolescents, and their families.

Real-time detection of vehicle-originated condensable particulate matter through thermodenuder integrated aerosol measurement method at tailpipes.

Condensable particulate matter (CPM) corresponds to primary particulate matter ≤2.5 µm (PM2.5) obtained through the condensation of gaseous air pollutants caused by temperature drops in the atmosphere. The internal combustion of vehicle engines can produce CPM because of the condensable compounds in the exhaust gas. Conventional CPM measurement methods have been developed for coal-fired power plants with stable emissions through sampling and off-site analyses. They are therefore unsuitable for detecting the rapidly changing vehicle-originated CPM. In addition, the current system for evaluating PM2.5 from vehicles, based on the particle measurement program (PMP) protocol, provides only the emission factors of total PM2.5 (and not CPM separately) at a fixed temperature (∼25 °C) and dilution ratio (∼ × 35). This study reports, for the first time, the development of a real-time detection method for vehicle-originated CPM through a thermodenuder (TD) integrated with real-time aerosol instruments. This method was designed to reduce the loss of CPM due to condensation and diffusion while sampling the exhaust gas. It permits the investigation of the effects of dilution gas temperature (5-45 °C) and dilution ratio (up to × 30) on the formation of CPM. During the feasibility test of this method using a diesel vehicle (Euro-4), the real-time total particle number concentrations (PNs) matched well with those obtained by a PMP protocol-based evaluation system. Moreover, this method detected PNs concentrations ten times higher than the detection limit (4 × 106 particles/cm3) of the PMP-based system. The emission factors of the total PM2.5 with a bulk density (1 g/cm3) measured by this method also showed consistency with the results of the PMP protocol. The mass emission factor of CPM determined by deploying the TD was ∼14.57 mg/km (∼63% contribution to the total PM2.5).

The mediating role of internalizing and externalizing symptoms in the relationship between childhood trauma and suicidality among adolescents: a structural equation model.

BACKGROUND: The objective of this study is to investigate the direct and indirect effects of childhood trauma, internalizing symptoms, and externalizing symptoms on suicidality among adolescents, thereby establishing a structural equation model. METHODS: The present study uses a cross-sectional descriptive design. Among 147 adolescents aged 12-17, 93 outpatients diagnosed with major depressive disorder and 54 controls were included in the study. They completed the Early Trauma Inventory Self-Report (Short Form) and Columbia Suicidality Severity Rating Scale. Their parents completed the Child Behavior Checklist. Analyses were performed using Pearson's correlation and structural equation modelling. RESULTS: Childhood trauma had both direct and indirect effects, via internalizing symptoms and externalizing symptoms, on suicidality. Internalizing symptoms had a direct effect on suicidality. Meanwhile, externalizing symptoms were not directly associated with suicidality, but indirectly associated via internalizing symptoms. CONCLUSIONS: Findings provide in-depth understanding of the mediating role of internalizing symptoms and externalizing symptoms in the relationship between childhood trauma and suicidality, suggesting that the therapeutic interventions for both internalizing symptoms and externalizing symptoms may be important to prevent suicide in adolescents with childhood trauma.

A Study of the Reliability and Validity of the Korean Version of DSM-5 Symptom Measure-Inattention and Anger for Parent and Guardian of Child Age 6 to 17.

OBJECTIVES: This study was conducted to investigate the reliability and validity of the Korean version of the DSM-5 Level 2 Cross-Cutting Symptom Measure-inattention [Swanson, Nolan and Pelham, version IV (SNAP-IV)] and anger [Patient-Reported Outcome Measurement Information System (PROMIS) Anger] for parents and guardians of children aged 6-17 years. METHODS: We included 104 children and adolescents diagnosed with attention-deficit/hyperactivity disorder (ADHD), ADHD with anxiety and depression, depressive disorder, anxiety disorder, and tic disorder with somatic symptoms (ADHD=41, depression=9, anxiety=14, ADHD+anxious depression=11, tic+somatic symptoms=29). Their ages ranged from 8 years to 15 years. The participants' mothers completed the SNAP-IV, PROMIS Anger scale, Korean version of the IOWA Conners Rating Scale (K-IOWA), and Korean ADHD Rating Scale (K-ARS) so that the reliability and validity of the SNAP-IV and PROMIS Anger scales, which are DSM-5 scales for assessing inattention and anger of children and adolescents, could be examined. RESULTS: The reliability coefficient of SNAP-IV (Cronbach's α) was 0.94. The correlation coefficients between SNAP-IV, K-IOWA inattention, and K-ARS inattention scores ranged from 0.73 to 0.86. The mean SNAP-IV scores of the ADHD and the ADHD+anxious depression groups were significantly higher than those of the anxiety and the tic+somatic symptoms groups. The reliability coefficient of the PROMIS Anger was 0.91. The correlation coefficient between PROMIS Anger and K-IOWA oppositional/defiant scores was 0.75. The PROMIS Anger mean score of the ADHD+anxious depression group tended to be higher than that of the other groups. CONCLUSION: These results suggest that the Korean version of the DSM-5 Level 2 Cross-Cutting Symptom Measure-inattention and anger for parent and guardian of child age 6-17 might be a reliable and valid test and may be useful for screening children and adolescents with ADHD.

A Brief Depression and Anxiety Rating Scale for Sexual Violence Victims.

OBJECTIVE: This study aimed to develop a brief self-report measure of depressive and anxiety symptoms in victims of sexual violence. METHODS: The sample, which consisted of 215 victims and 255 healthy controls, was recruited between December 2016 and November 2018 from eight Sunflower Centers. Eligible items were selected from existing scales of depression (CES-DC and CES-D) and anxiety (SAI-C and BAI) symptoms by item-total correlation coefficients and item response theory (IRT) analysis. Internal consistency coefficients were computed and the receiver operating characteristics curve was inspected to assess the validity of the brief scale and determine optimal cutoff scores. RESULTS: The brief scales showed high internal consistency across all age groups. The optimal cutoff score of brief depression scale was 1.5 for children, 2.5 for adolescents, and 2.5 for the adults. That of brief anxiety scale was 8.5, 6.5, and 3.5, respectively. CONCLUSION: The results underscore the need for age-appropriate screening measures of depressive and anxiety symptoms in victims of sexual violence.

The fruit of Acanthopanax senticosus Harms improves arterial stiffness and blood pressure: a randomized, placebo-controlled trial.

BACKGROUND/OBJECTIVES: Arterial stiffness and endothelial dysfunction are 2 of the independent predictors for cardiovascular disease, while Acanthopanax senticosus Harms (ASH) is a traditional medicinal plant that can improve cardiovascular health. This study aimed to investigate the efficacy of the fruit of ASH on vascular function in apparently healthy subjects. SUBJECTS/METHODS: A 12-week, randomized, double-blind, placebo-controlled design, consisting of healthy adults with at least 2 of the following 3 conditions: borderline high blood pressure (BP; 120 mmHg ≤ systolic BP ≤ 160 mmHg or 80 mmHg ≤ diastolic BP ≤ 100 mmHg), smoking (≥10 cigarettes/day), and borderline blood lipid levels (220 ≤ total cholesterol ≤ 240, 130 ≤ low density lipoprotein cholesterol ≤ 165, or 150 ≤ triglyceride ≤ 220 mg/dL). Randomly assigned 76 subjects who received a placebo or 2 doses of ASH fruit (low, 500 mg/day; high, 1,000 mg/day) completed the intervention. Brachial-ankle pulse wave velocity (baPWV), flow-mediated dilation, carotid intima-media thickness, and BP were measured both at baseline and following the 12-week intervention. Endothelial nitric oxide synthase (eNOS) phosphorylation was assessed by western blotting. RESULTS: Compared with the placebo group, the low-dose group showed more significant changes after the 12-week intervention period in terms of systolic BP (0.1 vs. -7.7 mmHg; P = 0.044), baPWV (31.3 vs. -98.7 cm/s; P = 0.007), and the ratio of phospho-eNOS/eNOS (0.8 vs. 1.22; P = 0.037). CONCLUSIONS: These results suggest that ASH fruit extract at 500 mg/day has the potential to improve BP and arterial stiffness via endothelial eNOS activation in healthy adults with smoking and the tendency of having elevated BP or blood lipid parameters. TRIAL REGISTRATION: Clinical Research Information Service Identifier: KCT0001072.

The indirect effect of peer problems on adolescent depression through nucleus accumbens volume alteration.

Literature suggests that neurobiological factors such as brain structure play an important role in linking social stress with depression in adolescence. We aimed to examine the role of subcortical volumetric alteration in the association between peer problems as one type of social stress and adolescent depression. We hypothesized that there would be indirect effects of peer problems on adolescent depression through subcortical volumetric alteration. Seventy eight adolescents with major depressive disorder (MDD) (age mean [SD] = 14.9 ± 1.5, 56 girls) and 47 healthy controls [14.3 ± 1.4, 26 girls]) participated in this study. High-resolution structural T1 images were collected using the Siemens 3T MR scanner. Subcortical volumes were segmented using the Freesurfer 6.0 package. Peer problems were assessed using the Peer-Victimization Scale and the Bullying-Behavior Scale. There was a significant indirect effect of peer problems on adolescent depression through nucleus accumbens (NAcc) volume alteration, but not through the amygdala and hippocampal volumes. This result supported our model, which stated that peer problems have indirect effects through subcortical volumetric alteration (i.e., increased NAcc volume) on adolescent depression. Our finding suggests that altered NAcc volume may serve as a pathway, through which peer problems as one type of social stressor contribute to adolescent depression.

Psychometric properties and factor structure of the Korean version of the screen for child anxiety related emotional disorders (SCARED).

BACKGROUND: The aim of this study was to examine the psychometric properties of the Korean version of Screen for Child Anxiety Related Emotional Disorders (SCARED) on a sample of Korean youths and to examine the cross-cultural differences in adolescents' anxiety. METHODS: Our study included 147 adolescents (ages 12-17, 92 girls), 93 with major depressive disorder and 54 as controls. Participants were evaluated using the Kiddie-Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime Version (K-SADS-PL), SCARED, Child Behavior Checklist (CBCL), Disruptive Behavioral Disorder Scale (DBD) and Attention Deficit Hyperactivity Disorder Rating Scale (ADHD-RS). Pearson's r and Cronbach's α values of the SCARED were calculated, and exploratory factor analysis was conducted. RESULTS: The Korean SCARED scores were correlated with the total anxiety scores of K-SADS-PL (r = 0.74) and the CBCL anxious/depressed subscale scores (r = 0.35). Results showed a five-factor structure with good internal consistency, in which some items were loaded on different factors compared to previous studies. CONCLUSIONS: The Korean SCARED demonstrated promising psychometric properties, and could be a valid scale for screening anxiety symptoms in primary care. The fact that different items comprised the factors may reflect the cultural difference between United States and Korea in experiencing anxiety.

Normal-But-Low Serum Folate Levels and the Risks for Cognitive Impairment.

OBJECTIVE: This study aimed to examine the association between normal-but-low folate levels and cognitive function in the elderly population using a prospective cohort study. METHODS: We analyzed 3,910 participants whose serum folate levels were within the normal reference range (1.5-16.9 ng/mL) at baseline evaluation in the population-based prospective cohort study named the "Korean Longitudinal Study on Cognitive Aging and Dementia." The association between baseline folate quartile categories and baseline cognitive disorders [mild cognitive impairment (MCI) or dementia] was examined using binary logistic regression analysis adjusting for confounding variables. The risks of incident MCI and dementia associated with the decline of serum folate level during a 4-year follow-up period were examined using multinomial logistic regression analysis. RESULTS: The lowest quartile group of serum folate (≥1.5, ≤5.9 ng/mL) showed a higher risk of cognitive disorders than did the highest quartile group at baseline evaluation (odds ratio 1.314, p=0.012). Over the 4 years of follow-up, the risk of incident dementia was 2.364 times higher among subjects whose serum folate levels declined from the 2nd-4th quartile group to the 1st quartile than among those for whom it did not (p=0.031). CONCLUSION: Normal-but-low serum folate levels were associated with the risk of cognitive disorders in the elderly population, and a decline to normal-but-low serum folate levels was associated with incident dementia. Maintaining serum folate concentration above 5.9 ng/mL may be beneficial for cognitive status.

Preparation of Black Hoof medicinal mushroom Phellinus linteus (Berk. et M.A. Curt.) Teng (Aphyllophoromycetideae) beta-glucan sulfate and in vitro tumor cell growth inhibitory activity.

Polysaccharide beta-glucans were extracted from the medicinal mushroom Phellinus linteus (Hymenochaetaceae, Aphyllophoromycetideae) and subjected to sulfation. Chemical modification of the beta-glucan was confirmed by structural analysis, and its biological properties were compared with those of native beta-glucan. The results of Fourier transform infrared spectroscopy and elemental analysis indicated that successive preparation of the sulfated derivative yielded a degree of substitution of 0.47. Nitric oxide production measured by the bronchoalveolar lavage (BAL) experiments increased 1.5-fold after sulfation. In addition, the introduction of sulfate groups into the beta-glucan chains improved in vitro growth inhibitory activity against SNU-C2A cells. Therefore, sulfated beta-glucan extracted from Ph. linteus may be beneficial for immune support due to its incorporation of functional groups into its polymer structure.

Structural and biological study of carboxymethylated Phellinus linteus polysaccharides.

Polysaccharides isolated from Phellinus linteus were chemically modified by carboxymethylation, and the structural and physiological properties of the derivative were investigated. 13C NMR spectroscopy showed that the polysaccharides extracted from P. linteus contained (1-3)-beta-glucans with a (1-6)-linkage. The carboxymetehylation of the P. linteus polysaccharides was confirmed by Fourier transform infrared spectroscopy, and the degree of substitution was obtained by the potentiometric titration, which was calculated to be 0.63. The bronchoalveolar lavage experiments showed that the carboxymethylated derivative raised the nitric oxide production. In addition, the carboxymethylation stimulated in vitro cytotoxic activity against the HT1080 cell line. Thus, the derivative exhibited the enhanced activity of immune systems, which would be explained by the improved water solubility and structural changes by carboxymethylation. However, a slight decrease in the 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity of the derivative was observed.