Showing papers by "Kenji Kosaka published in 2001"

Familial frontotemporal dementia and parkinsonism with a novel N296H mutation in exon 10 of the tau gene and a widespread tau accumulation in the glial cells.

Abstract: We report a 62-year-old Japanese man with familial frontotemporal dementia and a novel missense mutation (N296H) in exon 10 of the tau gene. The patient presented with frontal signs followed by temporal signs and parkinsonism. The brain showed localized frontotemporal lobe atrophy including the precentral gyrus and discoloration of the substantia nigra, and revealed severe neuronal loss with proliferation of tau-positive protoplasmic astroglia in the affected cerebral cortex, tau-positive coiled bodies and threads in the subcortical white matter, and tau-positive pretangle neurons in the subcortical and brain stem nuclei. There were no tau-positive neurofibrillary tangles, Pick bodies, tuft-shaped astrocytes or astrocytic plaques in the cerebral cortex. Immunoelectron microscopically, phosphorylated tau accumulated in both neurons and glial cells in different modalities, such as glial filaments in protoplasmic astroglia, straight tubules in coiled bodies, and free ribosomes in pretangle neurons. These findings suggest that tau proteins are not always assembled in abnormal filaments such as twisted ribbons, paired helical filaments and straight tubules in neurons and glial cells, which have been shown in previous cases with frontotemporal dementia and parkinsonism linked to chromosome 17. Immunoblotting of sarkosyl-insoluble tau exhibited accumulation of four-repeat tau isoforms in the brain. The N296H mutation may interfere with the ability of mutated tau to bind with microtubules and lead to tau aggregation. Further study is necessary to determine whether this mutation can account for the characteristic tau pathology of this case.

No evidence of an association between CYP2D6 polymorphisms among Japanese and dementia with Lewy bodies

Abstract: Dementia with Lewy bodies (DLB) is the second most frequent degenerative dementia among the elderly, following Alzheimer-type dementia (ATD). An association of DLB with CYP2D6*4, one of the cytochrome P450IID6 (debrisoquine 4-hydroxylase; CYP2D6) gene polymorphisms, was reported previously, but this is controversial. Moreover, these reports have been restricted to Caucasian populations. Therefore, we compared frequencies of CYP2D6*3, *4, and *10 mutant alleles in 17 Japanese DLB patients to those among Alzheimer-type dementia (ATD) patients and healthy controls. Polymerase chain reaction amplification and restriction fragment length polymorphism analyses were used for genotyping. No significant difference of genotype or mutant allele frequencies was detected between DLB, ATD, and healthy controls. The present results do not support the suggestion that the CYP2D6 gene is related to DLB susceptibility, at least in the Japanese population.

Frequency and distribution of TUNEL‐positive neurons in brains of dementia with Lewy bodies: Comparison with those in brains of Alzheimer's disease

Abstract: The present study investigated the frequency and distribution of TUNEL-positive neurons in brains of dementia with Lewy bodies (DLB) in comparison with those in brains of Alzheimer's disease (AD), Down syndrome (DS) and non-demented elderly persons. In DLB brains, TUNEL-positive neurons were increased in frequency compared with those in non-demented elderly brains, and showed a distribution similar to those in AD and DS brains. DLB cases with TUNEL-positive neurons showing severe Lewy pathology were all neocortical type, while DLB cases of the limbic type showing mild Lewy pathology did not demonstrate TUNEL-positive neurons. In addition, we investigated the relationships between TUNEL-positive neurons and pathological hallmarks of DLB or AD brains. TUNEL-positive neurons had no Lewy bodies or neurofibrillary tangles, and were not located within amyloid deposits. These findings suggest that neuronal damage showing DNA fragmentations occurs in DLB brains as well as in AD and DS brains, and that it is accelerated by progression of Lewy pathology as well as Alzheimer pathology, although it is not directly related to their pathological hallmarks.

Increasing in situ nick end labeling of oligodendrocytes in white matter of patients with Binswanger's disease.

Abstract: Increasing evidence suggests the presence of apoptotic cell death in many neurodegenerative diseases. However, in Binswanger's disease (BD), no information is available concerning the apoptosis-related pathologic changes that may occur in the white matter. To investigate whether apoptotic cell death is included in the pathophysiology of the white matter changes in BD, autopsied brains from patients with BD (n = 5) were compared with those of non-neurologic controls (n = 5). Terminal deoxynucleotidyl transferase-mediated dUTP in situ nick end labeling (TUNEL) was used as a marker for cell damage with DNA fragmentation. A proteolipid protein (PLP) messenger RNA (mRNA) hybridization signal was also used as a sensitive and specific marker of oligodendrocytes as well as glial fibrillary acidic protein (GFAP) immunoreactivity as a marker of astrocytes. There were frequent TUNEL-positive cells in the rarefied white matter of patients with BD. TUNEL-positive cells were found 15-fold more numerously in BD than in controls ( P

Neuropathological Studies on Dementia with Lewy Bodies

Abstract: We review here some of our recent neuropathological studies of dementia with Lewy bodies (DLB). Using immunohistochemistry with anti-α-synuclein and other antibodies, we point out (1) the possibility of dying-back degeneration in hippocampal pathology (2) more frequent coexistence of Lewy bodies and neurofibrillary tangles in the same neurons in the limbic areas than expected, and (3) the degeneration process of Lewy bodies, that the Lewy body degenerates slowly and appear extracellularly (ghost Lewy body) followed by microglias and astrocytes.

Brain Pathology of Dementias

Abstract: Dementia is one of the most important chronic organic brain syndromes caused by variable brain lesions. We first introduce our classification of dementias from a clincopathological point of view, and then show clinical features of each dementia as well as some examples causing it. The most frequent and important dementia-causing disorders in the elderly are so-called aging-associated dementing illnesses. Among them, non-Alzheimer degenerative dementias (NADD) have recently received a great deal of attention. Then, we introduce our classification of NADD from a clinico-pathological point of view and focus on dementia with Lewy bodies and dementia with neurofibrillary tangles.

An autopsied case of presenile dementia with tangles

Abstract: We report an autopsied case of presenile dementia showing neuropathologically abundant neurofibrillary tangles(NFT) without senile plaques(tangle only dementia). A Japanese woman developed memory disturbance when she was 60 years old. At age of 65, her ability to understand deteriorated and euphoria and wandering manifested but neither psychotic symptoms, including hallucination and delusion nor a change in character were observed. The patient was hospitalized at age 66 and a cranial CT scan revealed bilateral moderate atrophy of the cortex and moderate enlargement of the lateral ventricle, especially in the inferior horn. No lobar atrophy was detected. She exhibited an oral tendency and became appallic at her final stage and died at the age of 75. Autopsy showed that her brain weighed 850 g and neuropathological study showed numerous NFT mainly in the entorhinal (trans-entorhinal) region, subiculum, CA1-CA4, dentate gyrus, amygdara, subthalamic nucleus, basal nucleus of Meynert, substantia nigra and locus coeruleus. Severe neuronal loss with gliosis was noted in the temporal lobes including the hippocampal region. No senile plaque was detected in any of the brain regions. There have been some recent reports of patients with abundant NFT with the predominant involvement of the allocortex but no or very little senile plaque. All the patients in the reported cases were very elderly at onset(over 80 years of age). In our case, the onset was presenile and we could exclude any other diseases, that usually present with NFT, and to our knowledge, this is the first report of a presenile dementia with tangles.