Publications by authors named "Kazuhiro Niizato"

Tauopathies, including Alzheimer's disease and primary age-related tauopathy (PART), present heterogeneous clinico-pathological phenotypes that include dementia, aphasia, motor neuron diseases, and psychiatric symptoms. PART is neuropathologically characterized by the presence of neurofibrillary tangles in limbic regions without significant Aβ deposition, but its clinical features have not yet been fully established. Here, we present two patients with distinct psychosis and behavioral symptoms.

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Unlabelled: Several studies have reported a high prevalence of missed and delayed mild cognitive impairment (MCI) or mild dementia diagnosis, which could lead to delayed treatment and increased patient and caregiver burden.

Objectives: This study aimed to develop a new questionnaire for nonprofessionals to help detect early signs of MCI and dementia. Respondents included patients, family caregivers, or health professionals.

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Objectives: Recent neuroimaging studies have indicated that the mesolimbic pathway, known to work as reward neuronal circuitry, regulates cognitive-behavioral flexibility in prolonged anorexia nervosa (AN). Although AN is associated with the highest mortality rate among psychiatric disorders, there have been few neuropathological studies on this topic. This study aims to identify alterations of the reward circuitry regions, especially in the nucleus accumbens (NAcc), using AN brain tissues.

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Article Synopsis
  • * The accumulation of GlucA might be caused by genetic variations in the aldo-keto reductase family one member A1 (AKR1A1) enzyme, which is responsible for its reduction.
  • * Researchers discovered a specific genetic variant (c.753G > A) associated with schizophrenia, leading to a dysfunctional AKR1A1 protein, reduced enzyme activity, and higher GlucA levels, potentially contributing to treatment-resistant forms of the illness.
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Advanced glycation end products play a key role in the pathophysiology of schizophrenia. Cognitive impairment is one of the central features of schizophrenia; however, the association between advanced glycation end products and cognitive impairment remains unknown. This study investigated whether advanced glycation end products affect the cognitive domain in patients with schizophrenia.

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Anorexia nervosa (AN) is a serious eating disorder characterized by self-starvation and extreme weight loss. It has the highest mortality rate among all psychiatric disorders. Recent research indicates that malnutrition in AN patients induces various kinds of functional brain damage, but the pathophysiology of AN remains unclear.

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TAR DNA-binding protein of 43 kDa (TDP-43) is a major component of intracellular aggregates formed in brains of the patients with frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS), which are correctively referred to as TDP-43 proteinopathies. A link between Ataxin-2 (ATXN2) and TDP-43 proteinopathies was established when intermediate CAG repeat expansions of ATXN2 gene were found to be associated with ALS and it was shown that ATXN2 modifies TDP-43 toxicity. Although ATXN2's contribution to TDP-43 proteinopathies has been mostly studied in ALS, recent studies have shown that intermediate repeat expansions of ATXN2 also influence the phenotype of FTLD by an unknown mechanism.

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In elderly patients with so-called psychogenic physical symptoms, changes with age of the symptoms were discussed from the standpoint of geriatric psychiatry. In recent years, the diagnostic criteria for psychogenic physical symptoms have been revised and are closer to the definition of psychosomatic disorders. In aging, the aging phenomenon of each body organ progresses, and the brain is no exception.

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Objectives: Frontotemporal lobar degeneration (FTLD) is associated with accumulation of neurodegeneration-related protein, such as tau, TAR DNA-binding protein 43 (TDP-43), or fused in sarcoma protein (FUS). There have been very few systematic studies of the early symptoms of clinical phenotypes: behavioral variant frontotemporal dementia (bvFTD), semantic variant primary progressive aphasia (svPPA). Clinical subtypes and the patterns of atrophy reflect protein-accumulation patterns, but the relationship between early symptoms and pathological findings remains unclear.

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The neuropathological features of chronic traumatic encephalopathy (CTE), caused by repeated traumatic brain injury (TBI), include abnormal accumulations of hyper-phosphorylated tau (p-tau) protein in neurons, neurites and astrocytes, considered to progress via neuronal circuits in brains. Some previous reports suggest that a single severe TBI (sTBI) can also induce CTE and p-tau accumulation, but it is not clear whether the pathology is the same as that of repetitive TBI (rTBI). Since prefrontal leucotomy could be regarded as a model of sTBI, in this study we evaluated two autopsied schizophrenia with this procedure.

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Narcolepsy with cataplexy is a sleep disorder caused by a deficiency in hypocretin neurons in the lateral hypothalamus (LH). Here we performed an epigenome-wide association study (EWAS) of DNA methylation for narcolepsy and replication analyses using DNA samples extracted from two brain regions: LH (Cases: N = 4; Controls: N = 4) and temporal cortex (Cases: N = 7; Controls: N = 7). Seventy-seven differentially methylated regions (DMRs) were identified in the LH analysis, with the top association of a DMR in the myelin basic protein (MBP) region.

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Perineuronal nets comprise chondroitin sulfate moieties and their core proteins, and their neuropathological alterations have been implicated in schizophrenia. To explore the molecular mechanism of the perineuronal net impairments in schizophrenia, we measured the immunoreactivity of chondroitin sulfate moieties, major components of perineuronal nets, in three brain regions (postmortem dorsolateral prefrontal cortex, caudate nucleus, and hippocampus) of schizophrenia patients and control subjects. Immunoblotting for chondroitin 4-sulfate and chondroitin 6-sulfate moieties revealed a significant increase in intensity of a 180 kD band of chondroitin 4-sulfate immunoreactivity in the hippocampus of patients, although we detected no significant alteration in their immunoreactivities with any other molecular sizes or in other brain regions.

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Background: The behavioural variant of frontotemporal dementia (bvFTD) is the most common phenotype of frontotemporal lobar degeneration (FTLD). FTLD is divided into three main pathological subtypes: tau-positive FTLD (FTLD-tau), FTLD-TAR DNA-binding protein (TDP), and FTLD-Fused in sarcoma (FUS). At present, it is difficult to predict the underlying pathological subtypes of sporadic bvFTD before a patient's death.

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Article Synopsis
  • Recent research indicates that schizophrenia may be linked to abnormalities in myelin-oligodendrocytes, but there has been limited investigation into this area within the brains of those with the disease.
  • This study evaluated the expression of myelin oligodendrocyte glycoprotein (MOG) in postmortem brain tissue from 10 schizophrenia patients and 9 control subjects, focusing on the superior temporal gyrus and hippocampus.
  • Results showed significantly lower MOG expression and fiber structure thickness in long-term schizophrenia patients, suggesting that these brain changes may contribute to the progression of the disorder.
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Although delirium shares clinical characteristics with dementia with Lewy bodies (DLB), there is limited information regarding the relationship between delirium and Lewy body pathology. Here, we report an 89-year-old Japanese woman with an episode of delirium who was pathologically confirmed to have limbic-type Lewy body disease (LBD). Although she exhibited transient visual hallucinations during the delirium, she had no overt dementia.

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Choreoathetoid involuntary movements are rarely reported in patients with frontotemporal lobar degeneration (FTLD), suggesting their exclusion as a supportive feature in clinical diagnostic criteria for FTLD. Here, we identified three cases of the behavioral variant of frontotemporal dementia (bvFTD) that display chorea with fused in sarcoma (FUS)-positive inclusions (FTLD-FUS) and the basophilic inclusion body disease (BIBD) subtype. We determined the behavioral and cognitive features in this group that were distinct from other FTLD-FUS cases.

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Background: Cytogenomic mutations and chromosomal abnormality are implicated in the neuropathology of several brain diseases. Cell heterogeneity of brain tissues makes their detection and validation difficult, however. In the present study, we analyzed gene dosage alterations in brain DNA of schizophrenia patients and compared those with the copy number variations (CNVs) identified in schizophrenia patients as well as with those in Asian lymphocyte DNA and attempted to obtain hints at the pathological contribution of cytogenomic instability to schizophrenia.

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Background: Tangle-predominant dementia (TPD) is characterized neuropathologically by numerous neurofibrillary tangles in the limbic areas with no or occasional senile plaques throughout the brain. TPD is an under-recognized disease, while it is a common cause of dementia in those over 80 years of age. In the present study, we describe hyperphosphorylated tau (tau) accumulation in the nucleus accumbens (Acb) in patients with TPD.

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The function of each organ including the brain tends to decline with aging. This influences on the appearance of psychotic symptoms in the elderly. A manic state in the elderly is often atypical and different from that in younger and middle aged patients.

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Accumulating evidence suggests that advanced glycation end products, generated as a consequence of facilitated carbonyl stress, are implicated in the development of a variety of diseases. These diseases include neurodegenerative illnesses, such as Alzheimer disease. Pyridoxamine is one of the 3 forms of vitamin B6, and it acts by combating carbonyl stress and inhibiting the formation of AGEs.

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We investigated the pathological features of frontotemporal lobar degeneration (FTLD) with fused in sarcoma protein (FUS) accumulation (FTLD-FUS) in the Japanese population. Only one out of nine FTLD-FUS cases showed pathology that corresponds to atypical FTLD with ubiquitin-positive inclusions (aFTLD-U). Five were basophilic inclusion body disease (BIBD) and two were neuronal intermediate filament inclusion disease.

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A 30-year-old Japanese woman without relevant family history presented with a behavioral abnormality followed by motor weakness about 14 years later. The patient died at age 45. Post mortem examination revealed degeneration of the frontal and temporal lobes, as well as lower motor neurons in the brainstem and spinal cord.

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Glutamate is one of the key molecules involved in signal transduction in the brain, and dysfunction of glutamate signaling could be linked to schizophrenia. The SLC1A1 gene located at 9p24 encodes the glutamate transporter EAAT3/EAAC1. To investigate the association between the SLC1A1 gene and schizophrenia in the Japanese population, we genotyped 19 tagging single nucleotide polymorphisms (tagSNPs) in the SLC1A1 gene in 576 unrelated individuals with schizophrenia and 576 control subjects followed by replication in an independent case-control study of 1,344 individuals with schizophrenia and 1,344 control subjects.

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