Publications by authors named "Kimiko Shimizu"

Article Synopsis
  • - Increased lactate levels from glycolysis are being studied as potential markers for metabolic changes in neurons, linked to a drop in brain pH, which has been associated with various neuropsychiatric disorders like schizophrenia and autism.
  • - Research shows that these pH and lactate changes are common across different animal models, including those for depression, epilepsy, and Alzheimer's disease, though findings vary, particularly within the autism spectrum.
  • - A large-scale analysis indicated that higher lactate levels correlate with worse working memory performance, suggesting that altered brain chemistry might reflect underlying conditions across multiple disorders.
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Does the circadian clock keep running under such hypothermic states as daily torpor and hibernation? This fundamental question has been a research subject for decades but has remained unsettled. We addressed this subject by monitoring the circadian rhythm of clock gene transcription and intracellular Ca in the neurons of the suprachiasmatic nucleus (SCN), master circadian clock, under a cold environment. We discovered that the transcriptional and Ca rhythms are maintained at 22°C-28°C, but suspended at 15°C, accompanied by a large Ca increase.

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The daily activity in the brain is typically fine-tuned by the circadian clock in the local neurons as well as by the master circadian clock in the suprachiasmatic nucleus (SCN) of the hypothalamus. In the olfactory response, odor-evoked activity in the piriform cortex (PC) and olfactory behavior retain circadian rhythmicity in the absence of the SCN, yet how the circadian rhythm in the PC is achieved independently of the SCN remains elusive. Here, to define neurons regulating the circadian rhythm of the odor-evoked activity in the PC, we knocked out the clock gene Bmal1 in a host of specific neurons along the olfactory circuit.

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Cognitive functions depend on the time of day in various organisms. Previously, we found that 24-h recognition memory performance of nocturnal mice changes diurnally through SCOP protein-dependent regulation. It remains unknown whether diurnal change and SCOP-dependent regulation of memory performance are conserved across species with diurnal/nocturnal habits.

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Neuroactive steroids, termed neurosteroids, are synthesized locally in the brain and influence biological functions including cognition and behavior. These neurosteroids are synthesized from cholesterol by a series of cytochrome P450 enzymes, among which a member of P450 hydroxylase, cytochrome P450-7b1 (CYP7B1), catalyzes the formation of 7α-hydroxylated neurosteroids, 7α-hydroxypregnenolone (7α-OH-Preg) and 7α-hydroxydehydroepiandrosterone (7α-OH-DHEA). Here we demonstrated the occurrence of these neurosteroids in the mouse hippocampus after spatial-learning tasks.

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Alternative autophagy is an Atg5/Atg7-independent type of autophagy that contributes to various physiological events. We here identify Wipi3 as a molecule essential for alternative autophagy, but which plays minor roles in canonical autophagy. Wipi3 binds to Golgi membranes and is required for the generation of isolation membranes.

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Steroids that contain a 3-hydroxyl group (3-OH steroids) are widely distributed in nature. During analysis with ESI-MS, they easily become dehydrated while in the protonated form, resulting in the production of several precursor ions and leading to low sensitivity of detection. To address this analytical challenge, here, we developed a method for the quantitation of 3-OH steroids by LC-MS/MS coupled with post-column addition of lithium (Li) ions to the mobile phase.

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Article Synopsis
  • The 22q11.2 deletion syndrome (22q11.2DS) is linked to a higher risk of psychiatric disorders, but existing mouse models only represent a smaller version of the genetic deletion.
  • Researchers created a new mouse model (Del(3.0 Mb)/ +) using CRISPR/Cas9 to simulate the full 3.0-Mb deletion associated with 22q11.2DS.
  • This new model displayed behaviors aligning with schizophrenia symptoms, such as impaired fear memory and early visual processing, while also showing unique behaviors like hypoactivity and faster adaptation to jet lag, making it a valuable tool for studying related psychiatric disorders.
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After publication of our article [1] we were notified that the 5-point Likert-type scale in Additional file 1 needs to change from "1 to 5" to "0 to 4". The updated Additional file 1 is included in this correction.

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Pachychoroid neovasculopathy (PNV) shares some anatomical features with other pachychoroid spectrum diseases, but little is known about the characteristics on the treatment with anti-vascular endothelial growth factor (VEGF). We investigated the effect of choroidal structure and responses to anti-VEGF on the prognosis of pachychoroid neovasculopathy (PNV) and other types of neovascular age-related macular degeneration (non-PNV). Twenty-one eyes with PNV and 34 eyes with non-PNV who had anti-VEGF treatment were retrospectively reviewed.

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Purpose: To report three middle-aged cases with choroidal neovascularization (CNV) associated with early-onset drusen documented with optical coherence tomography angiography (OCTA).

Methods: Three patients with bilateral early-onset drusen were referred to our hospital. Fundus examination, fluorescein angiography, indocyanine green angiography, OCTA, and other multimodal imaging were performed.

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Background: The purpose of the study was to evaluate the 2-year outcome and predictive factors of treat-and-extend aflibercept in patients with eyes affected by typical neovascular age-related macula degenelation (t-AMD) or polypoidal choroidal vasculopathy (PCV), who were switched from ranibizumab.

Patients And Methods: The patients underwent three monthly aflibercept injections and subsequent administration following the treat-and-extend protocol. Sixty-two eyes of 62 patients were reviewed retrospectively.

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The aim of the current study is to investigate corneal biomechanical properties in detail using Ocular Response Analyzer (ORA) and Corvis ST (CST) tonometry and to analyze the association between corneal biomechanical properties and the frequency of intravitreal anti-vascular endothelial growth factor (VEGF) injections (F) in AS eyes with choroidal neovascularization (CNV). Twenty-eight eyes of 15 patients with AS were enrolled. Mean age of AS patients was 67.

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Purpose: To investigate the relationship between choroidal structure and visual acuity after intravitreal aflibercept therapy for polypoidal choroidal vasculopathy (PCV).

Methods: We conducted a retrospective, single-centre and observational study including 18 eyes of 18 patients with PCV (73.8 ± 10.

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The purpose of the current study was to investigate the association between visual function and retinal structure in central serous chorioretinopathy (CSC). In 22 eyes of 22 chronic CSC patients with serous retinal detachment at the macula, retinal sensitivity was measured using MP3 microperimetry (NIDEK, Japan) and mean sensitivity within two degrees (MS), four degrees (MS) and six degrees (MS), as well as foveal sensitivity (MS), were calculated. Retinal structure was measured using optical coherence tomography (OCT, Spectralis, Heidelberg).

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Background: Personal recovery is increasingly recognised as an important outcome measure in mental health services. This study aimed to develop a Japanese version of the Questionnaire about the Process of Recovery (QPR-J) and test its validity and reliability.

Methods: The study comprised two stages that employed the cross-sectional and prospective cohort designs, respectively.

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Purpose: To evaluate the morphological changes in retinal microstructures following modified photodynamic therapy (PDT) for chronic central serous chorioretinopathy.

Subjects And Methods: Retrospective study of 21 consecutive eyes (age, 59±8.0 years [mean ± SD]) of 21 patients with chronic central serous chorioretinopathy.

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Background This study aimed to evaluate the effects of the position of an acetic acid-induced gastric ulcer and the effects of prokinetic drugs on gastric emptying. Materials and Methods Male Sprague-Dawley rats were used in this study. Acetic acid ulcers were induced either in the region between the fundus and pylorus on the anterior wall of the stomach or in the glandular region on the greater curvature of the stomach to determine whether there were regional differences in the effect of the ulcers.

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Site-specific lesions are invaluable methods for investigating the function of brain regions within the central nervous system and can be used to study neural mechanisms of behaviors. Precise stereotaxic surgery is required to lesion small regions of the brain such as the suprachiasmatic nucleus (SCN), which harbors the master circadian clock. In this protocol, we describe stereotaxic surgery optimized for bilateral lesion of the mouse SCN by loading electric current.

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Learning and memory depend on the time of day in various organisms, but it is not clear whether and how the circadian clock regulates memory performance. Here we show that consolidation of long-term recognition memory is a circadian-regulated process, which is blunted by disruption of the hippocampal clock. We focused on SCOP, a key molecule regulating hippocampus-dependent long-term memory for objects.

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While disruption of the circadian clock triggers a spectrum of affective abnormalities, how the clock regulates mammalian emotionality remains unclear. Here, we characterized the time-of-day-dependent regulation of mouse anxiety-like behaviors. We show that anxiety-like behaviors are expressed in a circadian manner in mice and demonstrate that the clock machineries in the dorsal telencephalon (dTel) are required for the time-of-day-dependent regulation of anxiety-like behaviors.

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Aim: Some amino acids been known to influence gastric emptying. Thus we have evaluated the effects of straight alkyl chain, extra hydroxylated alkyl chain and branched chain amino acids on gastric emptying.

Materials And Methods: Gastric emptying was evaluated in rats after feeding with Racol (nutrient formulae) containing [1-(13)C] acetic acid.

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Daily behavioral rhythms in mammals are governed by the central circadian clock, located in the suprachiasmatic nucleus (SCN). The behavioral rhythms persist even in constant darkness, with a stable activity time due to coupling between two oscillators that determine the morning and evening activities. Accumulating evidence supports a prerequisite role for Ca(2+) in the robust oscillation of the SCN, yet the underlying molecular mechanism remains elusive.

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AML1/RUNX1 is a frequent target of chromosome translocations and mutations in myeloid and B-cell leukemias, and upregulation of AML1 is also observed in some cases of T-cell leukemias and lymphomas. This study shows that the incidence of thymic lymphoma in p53-null mice is less frequent in the Aml1(+/-) than in the Aml1(+/+) background. AML1 is upregulated in p53-null mouse bone-marrow cells and embryonic fibroblasts.

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Outreach services are very important in community mental health care. There are two types for outreach services. One is mental health activities, such as early intervention and consultation, and the other is intended to prevent recurrence and readmission by supporting the daily living activities of a patient in a community.

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