The aim of this study was to characterise the white matter damage involved in idiopathic normal pressure hydrocephalus (INPH) using diffusion tensor imaging (DTI) and the relationship between this ...damage and clinical presentation. Twenty patients with INPH, 20 patients with Alzheimer’s disease and 20 patients with idiopathic Parkinson’s disease (as disease control groups) were enrolled in this study. Mean diffusivity (MD) and fractional anisotropy (FA) were determined using DTI, and these measures were analysed to compare the INPH group with the control groups and with certain clinical correlates. On average, the supratentorial white matter presented higher MD and lower FA in the INPH group than in the control groups. In the INPH group, the mean hemispheric FA correlated with some of the clinical measures, whereas the mean hemispheric MD did not. On a voxel-based statistical map, white matter involvement with high MD was localised to the periventricular regions, and white matter involvement with low FA was localised to the corpus callosum and the subcortical regions. The total scores on the Frontal Assessment Battery were correlated with the FA in the frontal and parietal subcortical white matter, and an index of gait disturbance was correlated with the FA in the anterior limb of the left internal capsule and under the left supplementary motor area. DTI revealed the presence of white matter involvement in INPH. Whereas white matter regions with high MD were not related to symptom manifestation, those with low FA were related to motor and cognitive dysfunction in INPH.
The intracellular deposition of misfolded proteins is a common neuropathological hallmark of most neurodegenerative disorders. Increasing evidence suggests that these pathogenic proteins may spread ...to neighboring cells and induce the propagation of neurodegeneration.
In this study, we have demonstrated that α-synuclein (αSYN), a major constituent of intracellular inclusions in synucleinopathies, was taken up by neuronal and oligodendroglial cells in both a time- and concentration-dependent manner. Once incorporated, the extracellular αSYN was immediately assembled into high-molecular-weight oligomers and subsequently formed cytoplasmic inclusion bodies. Furthermore, αSYN uptake by neurons and cells of the oligodendroglial lineage was markedly decreased by the genetic suppression and pharmacological inhibition of the dynamin GTPases, suggesting the involvement of the endocytic pathway in this process.
Our findings shed light on the mode of αSYN uptake by neuronal and oligodendroglial cells and identify therapeutic strategies aimed at reducing the propagation of protein misfolding.
Abstract We evaluated a battery of functional tests for investigating the effects of edaravone, a free radical scavenger, in SOD1 transgenic (H46R) rat model of amyotrophic lateral sclerosis. ...Edaravone (1.5 or 3.0 mg/kg/h) or saline was administered intravenously to rats by continuous infusion (1 h per day) for 2 days, followed by a 2-day holiday. Lifetime and duration of illness were evaluated, and motor function was assessed using the hind-foot reflex test, landing foot-splay test, rota rod test and inclined plate test at a predetermined time point at which half of the control animals had died. Statistical comparison of motor functions of edaravone-treated and control SOD1 transgenic rats at an objectively determined time point was confirmed to be feasible. Edaravone-treated male rats showed significantly better performance in the landing foot-splay test. The present model seems suitable for evaluating motor function of H46R SOD1 transgenic rats, and be useful for examining the therapeutic potential of edaravone to treat amyotrophic lateral sclerosis.
Neuromyelitis optica (NMO) is a devastating neurologic disease characterized by severe optic neuritis and transverse myelitis. Recently, its disease-specific serum autoantibody, NMO-IgG, was ...discovered with indirect immunofluorescence. However, the substrates of the immunofluorescence assay were not human but mouse brain tissues, which could influence the sensitivity and specificity of the antibody. The target antigen of NMO-IgG was recently identified as aquaporin-4 (AQP4) water channel protein, which is mainly expressed in brain and spinal cord. In the present study, we have established human cell lines that stably express human AQP4 and used these cells to detect and titrate anti-AQP4 antibody present in the sera of patients with NMO by immunofluorescence assay. The results were compared with those of the original NMO-IgG assay. We tested the sera from 10 patients with NMO, 10 with MS and five with other neurological disorders. Among the patients with NMO, six were NMO-IgG-positive. However, using the new anti-AQP4 antibody assay, we showed that eight patients with NMO including the six NMO-IgG-positives were positive for anti-AQP4 antibody. The staining pattern of AQP4-expressing cells treated with each serum of these eight NMO patients corresponded to that with a commercially available anti-AQP4 antibody. The antibody titer (maximum serum dilution for positive staining) ranged from 64× to 16,384×. The serum dilution titers were reproducible in blinded studies. In contrast, the patients with MS or other neurological disorders showed negative for anti-AQP4 antibody. Thus, the newly developed anti-AQP4 antibody assay appears to have a higher sensitivity for NMO than the original NMO-IgG assay and is expected to be useful for the diagnosis of NMO.
Mutations in the fused in sarcoma (FUS, also known as translated in liposarcoma) gene have been recently discovered to be associated with familial amyotrophic lateral sclerosis (FALS) in African, ...European and American populations. In a Japanese family with FALS, we found the R521C FUS mutation, which has been reported to be found in various ethnic backgrounds. The family history revealed 23 patients with FALS among 46 family members, suggesting a 100% penetrance rate. They developed muscle weakness at an average age of 35.3 years, followed by dysarthria, dysphagia, spasticity and muscle atrophy. The average age of death was 37.2 years. Neuropathological examination of the index case revealed remarkable atrophy of the brainstem tegmentum characterized by cytoplasmic basophilic inclusion bodies in the neurons of the brainstem. We screened 40 FALS families in Japan and found 4 mutations (S513P, K510E, R514S, H517P) in exon 14 and 15 of FUS. Even in Asian races, FALS with FUS mutations may have the common characteristics of early onset, rapid progress and high penetrance rate, although in patients with the S513P mutation it was late-onset. Degeneration in multiple systems and cytoplasmic basophilic inclusion bodies were found in the autopsied cases.
The attentional set-shifting deficit that has been observed in Parkinson's disease (PD) has long been considered neuropsychological evidence of the involvement of meso-prefrontal and ...prefrontal-striatal circuits in cognitive flexibility. However, recent studies have suggested that non-dopaminergic, posterior cortical pathologies may also contribute to this deficit. Although several neuroimaging studies have addressed this issue, the results of these studies were confounded by the use of tasks that required other cognitive processes in addition to set-shifting, such as rule learning and working memory. In this study, we attempted to identify the neural correlates of the attentional set-shifting deficit in PD using a compound letter task and 18F-fluoro-deoxy-glucose (FDG) positron emission tomography during rest. Shift cost, which is a measure of attentional set-shifting ability, was significantly correlated with hypometabolism in the right dorsolateral prefrontal cortex, including the putative human frontal eye field. Our results provide direct evidence that dysfunction in the dorsolateral prefrontal cortex makes a primary contribution to the attentional set-shifting deficit that has been observed in PD patients.
Vascular endothelial growth factor (VEGF) is a secreted polypeptide and plays a pivotal role in angiogenesis in vivo. However, it also increases vascular permeability, and might exacerbate ischemic ...brain edema. The effect of this factor on the brain after transient ischemia was investigated in terms of infarct volume and edema formation, as well as cellular injury. After 90 minutes of transient middle cerebral artery occlusion, VEGF (1.0 ng/microL, 9 microL) was topically applied on the surface of the reperfused rat brain. A significant reduction of infarct volume was found in animals with VEGF application (P < 0.001) at 24 hours of reperfusion as compared with cases with vehicle treatment. Brain edema was significantly reduced in VEGF-treated animals (P = 0.01), and furthermore, extravasation of Evans blue was also decreased in those animals (P < 0.01). Terminal deoxynucleotidyl transferase-mediated dUTP-biotin in situ nick end labeling and immunohistochemical analysis for 70-kDa heat shock protein showed an amelioration of the stainings at 24 and 48 hours after reperfusion with VEGF treatment, which indicated reduction of neuronal damage. These results indicate that treatment with topical VEGF application significantly reduces ischemic brain damage, such as infarct volume, edema formation, and extravasation of Evans blue, and that the reductions were associated with that of neuronal injury.
We examined neuronal activity in the lateral prefrontal cortex of monkeys performing a path-planning task in a maze that required the planning of actions in multiple steps. The animals received an ...instruction that prompted them to prepare to move a cursor in the maze stepwise from a starting position to a goal position by operating manipulanda with either arm. During a delay period in which the animal prepared to start the first of three cursor movements to approach the pre-instructed goal, we identified two types of neuronal activity: the first type reflected the position within the maze to which the animal intended to move the cursor as an initial step (an immediate goal) and the second type reflected the position within the maze that was to be captured as a final goal. Neither type reflected motor responses. We propose that these two types of neuronal activity are neuronal correlates that represent immediate and ultimate behavioral goals. This finding implicates the prefrontal cortex in governing goal-oriented sequential behavior rather than sensorimotor transformation.
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