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Background: The presence of psychiatric disorders is widely recognized as one of the primary risk factors for suicide. A significant proportion of individuals receiving outpatient psychiatric treatment exhibit varying degrees of suicidal behaviors, which may range from mild suicidal ideations to overt suicide attempts. This study aims to elucidate the transdiagnostic symptom dimensions and associated suicidal features among psychiatric outpatients. Methods: The study enrolled patients who attended the psychiatry outpatient clinic at a tertiary hospital in South Korea (n = 1, 849, age range = 18–81; 61% women). A data-driven classification methodology was employed, incorporating a broad spectrum of clinical symptoms, to delineate distinctive subgroups among psychiatric outpatients exhibiting suicidality (n = 1189). A reference group of patients without suicidality (n = 660) was included for comparative purposes to ascertain cluster-specific sociodemographic, suicide-related, and psychiatric characteristics. Results: Psychiatric outpatients with suicidality (n = 1189) were subdivided into three distinctive clusters: the low-suicide risk cluster (Cluster 1), the high-suicide risk externalizing cluster (Cluster 2), and the high-suicide risk internalizing cluster (Cluster 3). Relative to the reference group (n = 660), each cluster exhibited distinct attributes pertaining to suicide-related characteristics and clinical symptoms, covering domains such as anxiety, externalizing and internalizing behaviors, and feelings of hopelessness. Cluster 1, identified as the low-suicide risk group, exhibited less frequent suicidal ideation, planning, and multiple attempts. In the high-suicide risk groups, Cluster 2 displayed pronounced externalizing symptoms, whereas Cluster 3 was primarily defined by internalizing and hopelessness symptoms. Bipolar disorders were most common in Cluster 2, while depressive disorders were predominant in Cluster 3. Discussion: Our findings suggest the possibility of differentiating psychiatric outpatients into distinct, clinically relevant subgroups predicated on their suicide risk. This research potentially paves the way for personalizing interventions and preventive strategies that address cluster-specific characteristics, thereby mitigating suicide-related mortality among psychiatric outpatients.

Biomarkers of suicidal behavior (SB), particularly peripheral biomarkers, may aid in the development of preventive and intervention strategies. The peripheral biomarkers of SB should be easily accessible, cost-effective, and minimally invasive. To identify peripheral biomarkers of SB, we summarized the current knowledge related to SB biomarkers with a focus on suicidal outcomes (suicidal ideation [SI], suicide risk [SR], suicide attempt [SA], and suicide death [SD]), measured site (center or periphery), and study design (cross-sectional or longitudinal). We also evaluated the central findings to validate the findings of peripheral biomarkers of SB. We found reduced peripheral interleukin (IL)-2 levels in individuals with a recent SA, higher cerebrospinal fluid (CSF) IL-6 levels in patients with a current SR and future SD, higher CSF tumor necrosis factor-α levels for current and future SRs, higher high-sensitivity C-reactive protein levels and lower peripheral total cholesterol levels for recent SAs, lower peripheral 5-HT levels for present SR, and a lower folate level for future SR and SA within 1 year. Previous studies have shown inconsistent associations of low peripheral leptin levels with SR and recent SA; therefore, further study is required. Given the multiple determinants of SB and weak associations with single biological markers, combinations of potential biological markers rather than single markers may improve the screening, diagnosis, and prediction of SB. [ABSTRACT FROM AUTHOR]

A previous study reported lateral habenula (LHb) lesions decelerated appetitive extinction. Therefore, we examined whether LHb activation accelerated appetitive extinction. In this study, rats received appetitive Pavlovian conditioning, pairing a conditioned stimulus (CS, light) with an unconditioned stimulus (food pellets), followed by CS-alone presentations. Chemogenetic LHb activation accelerated the decline in conditioned food-cup responses during extinction. The present results and the reports of previous LHb lesion studies suggest that LHb mediates appetitive extinction. [ABSTRACT FROM AUTHOR]

We describe the initial sequencing and assembly of the complete mitochondrial genome of Appasus japonicus Vuillefroy, 1864 (Hemiptera; Belostomatidae; Appasus). The mitochondrial genome of A. japonicus was found to be 18,608 bp. It contains thirteen protein-coding genes (PCGs), 22 transfer RNAs (tRNAs), two ribosomal RNAs (rRNAs) and an AT-rich region. The overall base composition of A. japonicus is A-41.9%, C-17.5%, G-11.9%, and T-28.7%. A phylogenetic analysis of 21 species within the order Hemiptera suggests that Diplonychus rusticus is most closely related to A. japonicus.

Background: Cambaroides similis is an endangered candidate species living in the stream of South Korea. Freshwater crayfish is known to decline rapidly not only domestically, but also internationally. Its decline is projected to be further exacerbated due to climate change. Understanding physical characteristics of the habitat is crucial for the conservation of an organism. However, comprehensive data regarding the distribution and physical habitat characteristics of C. similis are currently unavailable in South Korea. Thus, the objective of this study was to ascertain preferred ranges for water depth, current velocity, and streambed substrate of C. similis using Weibull model. Results: In this study, C. similis was found at 59 sites across 12 regions in South Korea. Its optimal water depth preferences ranged from 11.9 cm to 30.1 cm. Its current velocity preferences ranged from 9.8 cm s-1 to 29.1 cm s-1. Its substrate preferences ranged from -5.1 Fm to -2.5 Fm. Median values of central tendency were determined as follows: water depth of 21.4 cm, current velocity of 21.2 cm s-1, and substrate of -4.1 Fm. Mean values of central tendency were determined as follows: water depth of 21.8 cm, current velocity of 22.0 cm s-1, and substrate of -4.4 Fm. Mode values of central tendency were determined as follows: water depth of 21.7 cm, current velocity of 20.1 cm s-1, and substrate of -3.7 Fm. Conclusions: Based on habitat suitability analysis, physical microhabitat characteristics of C. similis within a stream were identified as Run section with coarse particle substrate, low water depth, and slow current velocity. Due to high sensitivity of these habitats to environmental changes, prioritized selection and assessment of threats should be carried out as a primary step. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the editor discusses various reports within the issue on topics including a potential therapeutic mechanism for action of extremely low-frequency high-voltage electric fields on a cell, exposure dose reduction during lateral spine tests with a water filter, and a death education curriculum model for the general public using the Developing a Curriculum (DACUM) method.

Abstract Serotonin (5-HT) plays an important role in cerebrovascular homeostasis and psychiatric disorders, including suicidality. Methylation of the serotonin transporter gene (SLC6A4) is associated with 5-HT expression. However, the prognostic roles of SLC6A4 methylation and suicidal ideation (SI) in long-term outcomes of stroke have not been evaluated. We investigated the independent and interactive effects of SLC6A4 methylation and SI immediately after stroke on long-term outcomes. Blood SLC6A4 methylation status and SI based on the suicide item of the Montgomery–Åsberg Depression Rating Scale were assessed in 278 patients at 2 weeks after stroke. After the index stroke, cerebro-cardiovascular events by SLC6A4 methylation status and SI were investigated over an 8–14-year follow-up period and using Cox regression models adjusted for a range of covariates. SLC6A4 hypermethylation and SI within 2 weeks of stroke both predicted worse long-term outcomes, independent of covariates. A significant interaction effect of SI and the methylation status of CpG 4 on long-term stroke outcomes was also identified. The association between SLC6A4 methylation and long-term adverse outcomes may be strengthened in the presence of SI within 2 weeks after stroke. Evaluation of methylation and SI status during the acute phase can be helpful when assessing stroke patients.

Abstract Background Terminalia chebula Retz. (Combretaceae) is a traditional herbal medicine that is widely used in the treatment of diabetes, immunodeficiency diseases, and stomach ulcer in Asia. However, the anti-amnesic effect of T. chebula has not yet been investigated. The present study was designed to determine whether T. chebula extract (TCE) alleviates amnesia induced by scopolamine in mice. We also investigated possible mechanisms associated with cholinergic system and anti-oxidant effects. Methods TCE (100 or 200 mg/kg) was orally administered to mice for fourteen days (days 1–14), and scopolamine was intraperitoneally injected to induce memory impairment for seven days (days 8–14). Learning and memory status were evaluated using the Morris water maze. Hippocampal levels of acetylcholine (ACh), acetylcholinesterase (AChE) and choline acetyltransferase (ChAT) were measured ex vivo. Levels of reactive oxygen species (ROS), nitric oxide (NO), and malondialdehyde (MDA) in the hippocampus were also examined. Results In the Morris water maze task, TCE treatment reversed scopolamine-induced learning and memory deficits in acquisition and retention. TCE reduced hippocampal AChE activities and increased ChAT and ACh levels in the scopolamine-induced model. Moreover, TCE treatment suppressed scopolamine-induced oxidative damage by ameliorating the increased levels of ROS, NO, and MDA. Conclusion These findings suggest that TCE exerts potent anti-amnesic effects via cholinergic modulation and anti-oxidant activity, thus providing evidence for its potential as a cognitive enhancer for amnesia.

Oxidative stress was implicated in the functional impairment of the frontal cortex observed in early Alzheimer’s disease (AD). To elucidate this role in an animal AD model, we assessed cognitive function of 4-month-old five familial AD (5XFAD) transgenic (Tg) mice using a learning strategy-switching task requiring recruitment of the frontal cortex and measuring levels of 4-hydroxy-2-trans-nonenal (4-HNE), a marker of oxidative stress, in their frontal cortex. Mice were sequentially trained in cued/response and place/spatial versions of the water maze task for four days each. 5XFAD and non-Tg mice exhibited equal performance in cued/response training. However, 5XFAD mice used spatial search strategy less than non-Tg mice in the spatial/place training. Immunoblot and immunofluorescence staining showed that 4-HNE levels increased in the frontal cortex, but not in the hippocampus and striatum, of 5XFAD mice compared to those in non-Tg mice. We report early cognitive deficits related to the frontal cortex and the frontal cortex’s oxidative damage in 4-month-old 5XFAD mice. These results suggest that 4-month-old 5XFAD mice be a useful animal model for the early diagnosis and management of AD.

The participation of the prefrontal cortex (PFC), hippocampus, and dorsal striatum in switching the learning task from cued to place learning were examined in C57BL/6 and DBA/2 mice, by assessing changed levels of phosphorylated CREB (pCREB). Mice of both strains first received cued training in a water maze for 4 days (4 trials per day), and were then assigned to one of four groups, one with no place training, and three with different durations of place training (2, 4, or 8 days). Both strains showed equal performance in cued training. After the switch to place training, C57BL/6 mice with 2 or 4 days of training performed significantly better than DBA/2 mice, but their superiority disappeared during the second half of an 8 days-place training period. The pCREB levels of these mice were measured 30 min after place training and compared with those of mice that received only cued training. Changes in pCREB levels of C57BL/6 mice were greater in the hippocampal CA3, hippocampal dentate gyrus, orbitofrontal and medial PFC than those of DBA/2 mice, when mice of both received the switched place training for 2 days. We further investigated the roles of orbitofrontal and medial PFC among these brain regions showing strain differences, by destroying each region using selective neurotoxins. C57BL/6 mice with orbitofrontal lesions were slower to acquire the place learning and continued to use the cued search acquired during the cued training phase. These findings indicate that mouse orbitofrontal cortex (OFC) pCREB is associated with behavioral flexibility such as the ability to switch a learning task.

Background: A number of neurological and neurodegenerative diseases share impaired cognition as a common symptom. Therefore, the development of clinically applicable therapies to enhance cognition has yielded significant interest. Previously, we have shown that activation of lysophosphatidic acid receptors (LPARs) via gintonin application potentiates synaptic transmission by the blockade of K+ channels in the mature hippocampus. However, whether gintonin may exert any beneficial impact directly on cognition at the neural circuitry level and the behavioral level has not been investigated. Methods: In the current study, we took advantage of gintonin, a novel LPAR agonist, to investigate the effect of gintonin-mediated LPAR activation on cognitive performances. Hippocampus-dependent fear memory test, synaptic plasticity in the hippocampal brain slices, and quantitative analysis on synaptic plasticity-related proteins were used. Results: Daily oral administration of gintonin for 1 wk significantly improved fear memory retention in the contextual fear-conditioning test in mice. We also found that oral administration of gintonin for 1 wk increased the expression of learning and memory-related proteins such as phosphorylated cyclic adenosine monophosphate-response element binding (CREB) protein and brain-derived neurotrophic factor (BDNF). In addition, prolonged gintonin administration enhanced long-term potentiation in the hippocampus. Conclusion: Our observations suggest that the systemic gintonin administration could successfully improve contextual memory formation at the molecular and synaptic levels as well as the behavioral level. Therefore, oral administration of gintonin may serve as an effective noninvasive, nonsurgical method of enhancing cognitive functions.

Many patients with diabetes are at increased risk of cognitive dysfunction and dementia. Diabetes mellitus is a vascular risk factor that may increase the risk of dementia through its associations with vascular dementia. We tested whether cognitive impairment could be exacerbated in combined injury using a rat model of chronic cerebral hypoperfusion with diabetes. We also determined whether a potent inhibitor of type III phosphodiesterase could prevent the cognitive decline caused by this combined injury.We used Otsuka Long–Evans Tokushima Fatty (OLETF) rats as a model of type II diabetes (T2DM) and Long–Evans Tokushima Otsuka (LETO) rats as a control. Chronic cerebral hypoperfusion was modeled by permanent bilateral common carotid artery occlusion (BCCAO). At 24 weeks, the non-diabetic and T2DM rats were randomly assigned into groups for the following experiments: analysis I (1) sham non-diabetic rats (n = 8); (2) hypoperfused non-diabetic rats (n = 9); (3) sham T2DM rats (n = 8); (4) hypoperfused T2DM rats (n = 9); analysis II- (1) sham T2DM rats without treatment (n = 8); (2) cilostazol-treated T2DM rats (n = 8); (3) hypoperfused T2DM rats (n = 9); and (4) hypoperfused T2DM rats and cilostazol treatment (n = 9). The rats were orally administered cilostazol (50 mg/kg) or vehicle once a day for 2 weeks after 24 weeks. Rats performed Morris water maze tasks, and neuronal cell death and neuroinflammation were investigated via Western blots and histological investigation.Spatial memory impairment was exacerbated synergistically in the hypoperfused T2DM group compared with the hypoperfused non-diabetic group and sham T2DBM group (P

Among the various phenotypes seen in Down syndrome (DS), mental retardation is the most common and most debilitating condition suffered by individuals with DS. The DYRK1A gene on human chromosome 21q22.2 encodes a subfamily of protein kinases that displays dual substrate specificities and is known to play a critical role in neurodevelopment. To study DS mental retardation, we have generated transgenic mice that contain only one copy of the complete human DYRK1A gene in a bacterial artificial chromosome. The transgenic mice showed significant impairment in hippocampal-dependent memory tasks in a Morris water maze. Interestingly, we observed shifts in both long-term potentiation and long-term depression, which suggests a role for DYRK1A in bidirectional synaptic plasticity. These mice represent the most clinically relevant DYRK1A mouse model to date and provide us a valuable tool for the in vivo study of mechanisms that underlie the learning and memory deficit in DS.

BACKGROUND: Chronic cerebral hypoperfusion induced by permanent occlusion of the bilateral common carotid artery (BCCAO) in rats has been commonly used for the study of Alzheimer's disease and vascular dementia. Despite the apparent cognitive dysfunction in rats with BCCAO, the molecular markers or pathways involved in the pathological alternation have not been clearly identified. METHODS: Temporal changes (sham, 21, 35, 45, 55 and 70 days) in gene expression in the hippocampus of rats after BCCAO were measured using time-course microarray analysis. Gene Ontology (GO) and pathway analyses were performed to identify the functional involvement of temporally regulated genes in BCCAO. RESULTS: Two major gene expression patterns were observed in the hippocampus of rats after BCCAO. One pattern, which was composed of 341 early up-regulated genes after the surgical procedure, was dominantly involved in immune-related biological functions (false discovery rate [FDR]