Publications by authors named "Kohyama J"

Chronic complete spinal cord injury (SCI) is difficult to treat because of scar formation and cavitary lesions. While human iPS cell-derived neural stem/progenitor cell (hNS/PC) therapy shows promise, its efficacy is limited without the structural support needed to address cavitary lesions. Our study investigated a combined approach involving surgical scar resection, decellularized extracellular matrix (dECM) hydrogel as a scaffold, and hNS/PC transplantation.

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Sjögren-Larsson syndrome (SLS) is an autosomal recessive leukodystrophy characterized by ichthyosis, intellectual disability, and progressive spastic paralysis caused by biallelic pathogenic variants in the ALDH3A2 gene that encodes the fatty aldehyde dehydrogenase, fatty aldehyde dehydrogenase (FALDH); FALDH catalyzes several metabolic reactions involved in fatty aldehyde oxidation. Only a few studies have been performed to determine the lipid profile of patients with SLS. In a previous postmortem study of the brain of a 65-year-old patient with SLS, lipidomic analysis revealed an accumulation of long-chain unsaturated ether lipid species in the white matter and gray matter.

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A significant number of adolescents experience sleepiness, primarily due to sleep deprivation. The detrimental effects of inadequate sleep on both physical and mental health are well documented, particularly during adolescence-a critical developmental stage that has far-reaching implications for later life outcomes. The International Classification of Diseases 11th Revision recently introduced the disorder termed 'insufficient sleep syndrome,' characterized by a persistent reduction in sleep quantity.

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The transplantation of neural stem/progenitor cells (NS/PCs) derived from human induced pluripotent stem cells (hiPSCs) has shown promise in spinal cord injury (SCI) model animals. Establishing a functional synaptic connection between the transplanted and host neurons is crucial for motor function recovery. To boost therapeutic outcomes, we developed an ex vivo gene therapy aimed at promoting synapse formation by expressing the synthetic excitatory synapse organizer CPTX in hiPSC-NS/PCs.

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Bone marrow endothelial cells (BMECs) play a key role in bone formation and haematopoiesis. Although recent studies uncovered the cellular taxonomy of stromal compartments in the bone marrow (BM), the complexity of BMECs is not fully characterized. In the present study, using single-cell RNA sequencing, we defined a spatial heterogeneity of BMECs and identified a capillary subtype, termed type S (secondary ossification) endothelial cells (ECs), exclusively existing in the epiphysis.

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Glioblastoma is characterized by diffuse infiltration into the normal brain. Invasive glioma stem cells (GSCs) are an underlying cause of treatment failure. Despite the use of multimodal therapies, the prognosis remains dismal.

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Although neural stem/progenitor cells derived from human induced pluripotent stem cells (hiPSC-NS/PCs) are expected to be a cell source for cell-based therapy, tumorigenesis of hiPSC-NS/PCs is a potential problem for clinical applications. Therefore, to understand the mechanisms of tumorigenicity in NS/PCs, we clarified the cell populations of NS/PCs. We established single cell-derived NS/PC clones (scNS/PCs) from hiPSC-NS/PCs that generated undesired grafts.

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Spinal cord injury (SCI) is damage to the spinal cord due to trauma or health conditions, resulting in lesions in the spinal cord. Currently, available treatment includes surgical intervention to decompress or stabilize a dislocated loose spine, steroid drugs to reduce inflammation, and subsequent rehabilitation. As there is a rising number of SCI globally, radical treatments to recover spinal cord functions have become highly anticipated.

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A mutation in the chromatin remodeler chromodomain helicase DNA-binding 7 (CHD7) gene causes the multiple congenital anomaly CHARGE syndrome. The craniofacial anomalies observed in CHARGE syndrome are caused by dysfunctions of neural crest cells (NCCs), which originate from the neural tube. However, the mechanism by which CHD7 regulates the function of human NCCs (hNCCs) remains unclear.

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Various culture methods have been developed for maintaining human pluripotent stem cells (PSCs). These PSC maintenance methods exhibit biased differentiation; for example, feeder-dependent PSCs efficiently yield cerebral organoids, but it is difficult to generate organoids from feeder-free PSCs. It remains unknown how PSC maintenance conditions affect differentiation.

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Expectations for neural stem/progenitor cell (NS/PC) transplantation as a treatment for spinal cord injury (SCI) are increasing. However, whether and how grafted cells are incorporated into the host neural circuit and contribute to motor function recovery remain unknown. The aim of this project was to establish a novel non-invasive in vivo imaging system to visualize the activity of neural grafts by which we can simultaneously demonstrate the circuit-level integration between the graft and host and the contribution of graft neuronal activity to host behaviour.

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Objective: To explore the prevalence of and relationship between caregiver-reported sleep problems and sleep-related desired areas of change in young children (0-36 months) in a multinational sample.

Methods: Caregivers (96.5% mothers) of 2219 young children (birth to 3 years; M = 13.

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The skeletal system consists of bones and teeth, both of which are hardened via mineralization to support daily physical activity and mastication. The precise mechanism for this process, especially how blood vessels contribute to tissue mineralization, remains incompletely understood. Here, we established an imaging technique to visualize the 3D structure of the tooth vasculature at a single-cell level.

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Human-induced pluripotent stem cell-derived neural stem/progenitor cell (hiPSC-NS/PC) transplantation during the acute phase of spinal cord injury (SCI) is not effective due to the inflammatory response occurring immediately after SCI, which negatively impacts transplanted cell survival. Therefore, we chose to study the powerful chemoattractant complement C5a as a method to generate a more favorable transplantation environment. We hypothesized that suppression of the inflammatory response immediately after SCI by C5a receptor antagonist (C5aRA) would improve the efficacy of hiPSC-NS/PCs transplantation for acute phase SCI.

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Background: Both late and irregular caloric intakes are becoming common, especially among young adults. This study aimed to investigate features of pupils in Japan following different dinner habits.

Methods: Dinner habits were categorized into 3 types: non-late regular, regular but late, and irregular.

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Transplantation of neural stem/progenitor cells (NS/PCs) derived from human induced pluripotent stem cells (hiPSCs) is considered to be a promising therapy for spinal cord injury (SCI) and will soon be translated to the clinical phase. However, how grafted neuronal activity influences functional recovery has not been fully elucidated. Here, we show the locomotor functional changes caused by inhibiting the neuronal activity of grafted cells using a designer receptor exclusively activated by designer drugs (DREADD).

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Sleep quality is difficult to define objectively [...

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Sleep is one of the basic physiological processes for human survival. Both sleep quantity and sleep quality are fundamental components of sleep. This review looks at both sleep quantity and sleep quality, considering how to manage the complex but probably unavoidable physiological phenomenon of sleep.

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Objective: To assess associations of adolescents' lifestyle habits with their daytime functioning in Japan.

Methods: A total of 2,722 questionnaires obtained from pupils in grades 5 to 12 in Japan were assessed by the multiple comparison test to determine significant differences in the lifestyle habits among the self-reported academic performance categories (AP1: very good; AP2: good; AP3: not good; AP4: poor).

Results: The average non-school-day screen time of AP4 pupils was significantly longer than that of AP1 pupils in elementary and junior high schools.

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Human mesenchymal stem/stromal cells (hMSCs) have garnered enormous interest as a potential resource for cell-based therapies. However, the molecular mechanisms regulating senescence in hMSCs remain unclear. To elucidate these mechanisms, we performed gene expression profiling to compare clonal immature MSCs exhibiting multipotency with less potent MSCs.

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Social jetlag (SJL) is the difference between the midpoint time of sleep between weekend and weekday. SJL is experienced by many adolescents and is a matter of concern in public health. In private experiences, pupils who were forced to wake up early on non-school day mornings to engage in hard physical activity and who had little time for sleep on non-school nights were identified.

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Cell-based therapy targeting spinal cord injury (SCI) is an attractive approach to promote functional recovery by replacing damaged tissue. We and other groups have reported the effectiveness of transplanting neural stem/progenitor cells (NS/PCs) derived from human induced pluripotent stem cells (hiPSCs) in SCI animal models for neuronal replacement. Glial replacement is an additional approach for tissue repair; however, the lack of robust procedures to drive iPSCs into NS/PCs which can produce glial cells has hindered the development of glial cell transplantation for the restoration of neuronal functions after SCI.

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Purpose: Not enough attention has been paid to defecation habits in Japan. This study aimed to emphasize the importance of defecation habits on health and function in Japanese pupils.

Methods: Using multiple regression analysis, 2,722 questionnaires obtained from pupils in grades 5 to 12 were analyzed to determine lifestyle habits associated with defecation frequency.

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