Publications by authors named "Hitoshi Shimada"

Article Synopsis
  • The study focuses on the need for an objective method to evaluate and compare different computer-aided detection (CADe) algorithms used in colorectal cancer screening, as their performance varies and no standard exists.
  • A modified Delphi approach was employed, where 25 experts generated and prioritized scoring criteria over eight months, ultimately identifying six key metrics, including sensitivity and adenoma detection rate.
  • The resulting criteria aim to guide the development and improvement of CADe software, with future research suggested to validate these metrics on benchmark video datasets.
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Background: Tau accumulation in the nucleus basalis of Meynert (nbM) has been documented in Alzheimer's disease (AD), but its relationship to neuropathological changes in other brain regions and cognitive deficits remains unclear, particularly between early-onset AD (EOAD) and late-onset AD (LOAD).

Objective: To evaluate tau accumulation patterns in the nbM and other brain regions in EOAD and LOAD using F-florzolotau PET and examine correlations with cognitive function.

Methods: Thirty-eight amyloid-positive AD patients (15 EOAD, 23 LOAD) and 46 healthy controls underwent F-florzolotau PET.

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Amyloid PET plays a crucial role in the early diagnosis of Alzheimer's disease and the determination of the feasibility of disease-modifying therapies. It offers several advantages, including high sensitivity and specificity, minimal invasiveness, and the ability to provide spatial evaluation, all of which contribute to the optimization of dementia care. However, proper use and interpretation of the results require a thorough understanding of their limitations.

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  • A new small-molecule ligand called C05-05 has been developed to visualize α-synuclein deposits in the brains of living subjects, which is important for understanding Parkinson's disease (PD) and dementia with Lewy bodies (DLB).
  • In studies involving mouse and marmoset models, C05-05 enabled detection of dynamic changes in α-synuclein fibril formation and structural disruptions within neural pathways.
  • PET imaging revealed that C05-05 signals were significantly stronger in the midbrains of PD and DLB patients compared to healthy individuals, suggesting its potential for diagnostic and therapeutic advancements in these conditions.
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Objective: Although astrocytic pathology is a pathological hallmark of progressive supranuclear palsy (PSP), its pathophysiological role remains unclear. This study aimed to assess astrocyte reactivity in vivo in patients with PSP. Furthermore, we investigated alterations in brain lactate levels and their relationship with astrocyte reactivity.

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  • The study investigates the genetic basis of frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP-17) by analyzing multiple family members with different disease symptoms.
  • Researchers performed genetic and biochemical tests, identifying a specific mutation (c.896_897insACA) in the MAPT gene that correlates with reduced tau protein functionality and abnormal tau aggregation in affected individuals.
  • The findings indicate that this mutation leads to symptoms resembling Parkinson's disease initially, progressing to atypical features like progressive supranuclear palsy, highlighting the need for further research on MAPT mutations and their effects.
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Frontotemporal dementia refers to a group of neurodegenerative disorders with diverse clinical and neuropathological features. neuropathological assessments of frontotemporal dementia at an individual level have hitherto not been successful. In this study, we aim to classify patients with frontotemporal dementia based on topologies of tau protein aggregates captured by PET with F-florzolotau (aka F-APN-1607 and F-PM-PBB3), which allows high-contrast imaging of diverse tau fibrils in Alzheimer's disease as well as in non-Alzheimer's disease tauopathies.

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In Alzheimer's disease (AD), aggregated abnormal proteins induce neuronal dysfunction. Despite the evidence supporting the association between tau proteins and brain atrophy, further studies are needed to explore their link to neuronal dysfunction in the human brain. To clarify the relationship between neuronal dysfunction and abnormal proteins in AD-affected brains, we conducted magnetic resonance spectroscopic imaging (MRSI) and assessed the neurofilament light chain plasma levels (NfL).

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  • Corticobasal syndrome (CBS) is a neurodegenerative disorder marked by symptoms like parkinsonism, limb apraxia, and language issues, often linked to tauopathies, while Foix-Chavany-Marie syndrome (FCMS) presents differently, featuring facial and speech difficulties, typically due to stroke or TDP-43 proteinopathy.
  • A clinical case of a 68-year-old woman initially thought to have FCMS progressively developed symptoms that led to a final diagnosis of CBS, characterized by significant speech degradation and neurological signs reflective of frontal lobe dysfunction.
  • Neuroimaging revealed 4-repeat tauopathy as the underlying pathology of CBS, and despite treatment efforts, the patient’s condition worsened rapidly, leading
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Background: Deterioration of the oral environment is one of the risk factors for dementia. A previous study of an Alzheimer's disease (AD) model mouse suggests that tooth loss induces denervation of the mesencephalic trigeminal nucleus and neuroinflammation, possibly leading to accelerated tau dissemination from the nearby locus coeruleus (LC).

Objective: To elucidate the relevance of oral conditions and amyloid-β (Aβ) and tau pathologies in human participants.

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Objective: Increasing evidence suggests that reactive astrocytes are associated with Alzheimer's disease (AD). However, its underlying pathogenesis remains unknown. Given the role of astrocytes in energy metabolism, reactive astrocytes may contribute to altered brain energy metabolism.

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  • The study investigates the role of increased excitatory signals in autism, focusing on elevated levels of glutamate and its relation to astrocyte activation and dopamine signaling.
  • Using imaging techniques, researchers compared 18 adults with high-functioning autism to 20 typically developed individuals, finding significant increases in glutamate, glutamine, and myo-inositol levels in the autism group.
  • Results indicate a correlation between glutamine levels and dopamine receptor binding, suggesting that heightened excitation and astrocyte activity may contribute to autism's symptoms by disrupting normal inhibitory dopamine signaling.
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Introduction: Recently, an increasing number of tau tracers have become available. There is a need to standardize quantitative tau measures across tracers, supporting a universal scale. We developed several cortical tau masks and applied them to generate a tau imaging universal scale.

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Background: Central serotonin (5-hydroxytryptamine [5-HT]) neurotransmission has been implicated in the etiology of depression. Most antidepressants ameliorate depressive symptoms by increasing 5-HT at synaptic clefts, but their effect on 5-HT receptors has yet to be clarified. 11C-WAY-100635 and 18F-MPPF are positron emission tomography (PET) radioligands for 5-HT1A receptors.

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We report a 63-year-old female patient with progressive supranuclear palsy (PSP). She presented predominant postural instability and "saccadic ping-pong gaze" (SPPG). She had unprovoked falls recurrently within a year from the onset of gait disturbance.

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Patients with progressive supranuclear palsy (PSP) frequently exhibit apathy but the neuropathological processes leading to this phenotype remain elusive. We aimed to examine the involvement of tau protein depositions, oxidative stress (OS), and neuronal loss in the apathetic manifestation of PSP. Twenty patients with PSP and twenty-three healthy controls were enrolled.

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Positron emission tomography (PET) with F-PM-PBB3 (F-APN-1607, F-Florzolotau) enables high-contrast detection of tau depositions in various neurodegenerative dementias, including Alzheimer's disease (AD) and frontotemporal lobar degeneration (FTLD). A simplified method for quantifying radioligand binding in target regions is to employ the cerebellum as a reference (CB-ref) on the assumption that the cerebellum has minimal tau pathologies. This procedure is typically valid in AD, while FTLD disorders exemplified by progressive supranuclear palsy (PSP) are characterized by occasional tau accumulations in the cerebellum, hampering the application of CB-ref.

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Background: We recently developed a positron emission tomography (PET) probe, [ F]PM-PBB3, to detect tau lesions in diverse tauopathies, including mixed three-repeat and four-repeat (3R + 4R) tau fibrils in Alzheimer's disease (AD) and 4R tau aggregates in progressive supranuclear palsy (PSP). For wider availability of this technology for clinical settings, bias-free quantitative evaluation of tau images without a priori disease information is needed.

Objective: We aimed to establish tau PET pathology indices to characterize PSP and AD using a machine learning approach and test their validity and tracer capabilities.

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The Japanese Society of Neurology discusses research, education, and medical care in the field of neurology and makes recommendations to the national government. Dr. Mizusawa, the former representative director of the Japanese Society of Neurology, selected committee members and made "Recommendations for Promotion of Research for Overcoming Neurological Diseases" in 2013.

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The Japanese Society of Neurology discusses research, education, and medical care in the field of neurology and makes recommendations to the national government. Dr. Mizusawa, the former representative director of the Japanese Society of Neurology, selected committee members and made "Recommendations for Promotion of Research for Overcoming Neurological Diseases" in 2013.

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Introduction: Corticobasal degeneration (CBD) is the most common neuropathological substrate for clinically diagnosed corticobasal syndrome (CBS), while identifying CBD pathology in living individuals has been challenging. This study aimed to examine the capability of positron emission tomography (PET) to detect CBD-type tau depositions and neuropathological classification of CBS.

Methods: Sixteen CBS cases diagnosed by Cambridge's criteria and 12 cognitively healthy controls (HCs) underwent PET scans with C-PiB, C-PBB3, and F-FDG, along with T1-weighted magnetic resonance imaging.

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