Association of schizophrenia onset age and white matter integrity with treatment effect of D-cycloserine: a randomized placebo-controlled double-blind crossover study.

BACKGROUND: It has been reported that drugs which promote the N-Methyl-D-aspartate-type glutamate receptor function by stimulating the glycine modulatory site in the receptor improve negative symptoms and cognitive dysfunction in schizophrenia patients being treated with antipsychotic drugs. METHODS: We performed a placebo-controlled double-blind crossover study involving 41 schizophrenia patients in which D-cycloserine 50 mg/day was added-on, and the influence of the onset age and association with white matter integrity on MR diffusion tensor imaging were investigated for the first time. The patients were evaluated using the Positive and Negative Syndrome Scale (PANSS), Scale for the Assessment of Negative Symptoms (SANS), Brief Assessment of Cognition in Schizophrenia (BACS), and other scales. RESULTS: D-cycloserine did not improve positive or negative symptoms or cognitive dysfunction in schizophrenia. The investigation in consideration of the onset age suggests that D-cycloserine may aggravate negative symptoms of early-onset schizophrenia. The better treatment effect of D-cycloserine on BACS was observed when the white matter integrity of the sagittal stratum/ cingulum/fornix stria terminalis/genu of corpus callosum/external capsule was higher, and the better treatment effect on PANSS general psychopathology (PANSS-G) was observed when the white matter integrity of the splenium of corpus callosum was higher. In contrast, the better treatment effect of D-cycloserine on PANSS-G and SANS-IV were observed when the white matter integrity of the posterior thalamic radiation (left) was lower. CONCLUSION: It was suggested that response to D-cycloserine is influenced by the onset age and white matter integrity. TRIAL REGISTRATION: UMIN Clinical Trials Registry (number UMIN000000468 ). Registered 18 August 2006.

Biochemical classification of tauopathies by immunoblot, protein sequence and mass spectrometric analyses of sarkosyl-insoluble and trypsin-resistant tau.

Intracellular filamentous tau pathology is the defining feature of tauopathies, which form a subset of neurodegenerative diseases. We have analyzed pathological tau in Alzheimer's disease, and in frontotemporal lobar degeneration associated with tauopathy to include cases with Pick bodies, corticobasal degeneration, progressive supranuclear palsy, and ones due to intronic mutations in MAPT. We found that the C-terminal band pattern of the pathological tau species is distinct for each disease. Immunoblot analysis of trypsin-resistant tau indicated that the different band patterns of the 7-18 kDa fragments in these diseases likely reflect different conformations of tau molecular species. Protein sequence and mass spectrometric analyses revealed the carboxyl-terminal region (residues 243-406) of tau comprises the protease-resistant core units of the tau aggregates, and the sequence lengths and precise regions involved are different among the diseases. These unique assembled tau cores may be used to classify and diagnose disease strains. Based on these results, we propose a new clinicopathological classification of tauopathies based on the biochemical properties of tau.

Simplification of the modified Gallyas method.

The Gallyas method is a silver impregnation technique that is essential in the field of neuropathology because of its high sensitivity for the detection of argentophilic inclusion bodies in the central nervous system. In Japan, the Gallyas method has improved and is widely used as the "modified Gallyas method". However, this method is not popularly used in general pathology laboratories because of the need for special reagents, several staining processes, and skilled techniques. The objective of the current study was to provide a simplified Gallyas method. We omitted the lanthanum nitrate step from the staining process and verified the adequacy in comparison with the original method as well as immunohistochemistry, using specimens from patients of Alzheimer's disease, argyrophilic grain disease, multiple system atrophy, Pick's disease, and Lewy body disease. The simplified method provided good staining to all the structures in archival tissues, compared with the modified Gallyas method in a significantly shorter staining time. The lanthanum nitrate step can be omitted from the modified Gallyas method, resulting in reduction in the number of reagents required and shortening of the staining time.

Neurodegenerative changes in patients with clinical history of bipolar disorders.

Neurodegeneration in bipolar disorder (BPD) is poorly understood. Therefore, the current study was designed to assess the immunohistochemical changes in neurodegenerative markers in patients with BPD. Eleven consecutive autopsy cases diagnosed with BPD were analyzed. Sections were obtained from archival paraffin blocks of representative areas and stained using conventional methods, as well as immunostained with several antibodies to screen for neurodegenerative diseases. Age- and non-argyrophilic grains (AGs) degeneration matched controls were selected for each case. Clinical information was retrospectively collected from medical charts. All patients were men, and the average age of death was 70 years. Neuropathological diagnoses included dementia with grains (2), argyrophilic grain disease (2), corticobasal degeneration (CBD, 1), Lewy body disease (1), hypoxic encephalopathy (1) and cerebral infarction (1). All cases showed AGs to various degrees. Three patients died in their 50s; one demonstrated dementia with Lewy bodies, while the other two showed abundant AGs in the thalamus and amygdala. Of the three patients who died in their 60s, one showed AGs preferentially in the thalamus and amygdala, while the others demonstrated limbic predominance. The patients who died in/after their 70s demonstrated AGs similar to controls, except for the patient with CBD. Our data provides potentiality that neurodegenerative diseases may be an underlying pathology in certain cases of BPD.

Immunohistochemical characterization of CD33 expression on microglia in Nasu-Hakola disease brains.

Nasu-Hakola disease (NHD) is a rare autosomal recessive disorder, characterized by formation of multifocal bone cysts and development of leukoencephalopathy, caused by genetic mutations of either DNAX-activation protein 12 (DAP12) or triggering receptor expressed on myeloid cells 2 (TREM2). Although increasing evidence suggests a defect in microglial TREM2/DAP12 function in NHD, the molecular mechanism underlying leukoencephalopathy with relevance to microglial dysfunction remains unknown. TREM2, by transmitting signals via the immunoreceptor tyrosine-based activation motif (ITAM) of DAP12, stimulates phagocytic activity of microglia, and ITAM signaling is counterbalanced by sialic acid-binding immunoglobulin (Ig)-like lectins (Siglecs)-mediated immunoreceptor tyrosine-based inhibitory motif (ITIM) signaling. To investigate a role of CD33, a member of the Siglecs family acting as a negative regulator of microglia activation, in the pathology of NHD, we studied CD33 expression patterns in five NHD brains and 11 controls by immunohistochemistry. In NHD brains, CD33 was identified exclusively on ramified and amoeboid microglia accumulated in demyelinated white matter lesions but not expressed in astrocytes, oligodendrocytes, or neurons. However, the number of CD33-immunoreactive microglia showed great variability from case to case and from lesion to lesion without significant differences between NHD and control brains. These results do not support the view that CD33-expressing microglia play a central role in the development of leukoencephalopathy in NHD brains.

Clinical impact of (11)C-Pittsburgh compound-B positron emission tomography carried out in addition to magnetic resonance imaging and single-photon emission computed tomography on the diagnosis of Alzheimer's disease in patients with dementia and mild cognitive impairment.

AIMS: The purpose of this study was to evaluate the clinical impact of addition of [(11)C]Pittsburgh compound-B positron emission tomography ((11)C-PiB PET) on routine clinical diagnosis of Alzheimer's disease (AD) dementia and mild cognitive impairment (MCI), and to assess diagnostic agreement between clinical criteria and research criteria of the National Institute on Aging-Alzheimer's Association. METHODS: The diagnosis in 85 patients was made according to clinical criteria. Imaging examinations, including both magnetic resonance imaging and single-photon emission computed tomography/computed tomography to identify neuronal injury (NI), and (11)C-PiB PET to identify amyloid were performed, and all subjects were re-categorized according to the research criteria. RESULTS: Among 40 patients with probable AD dementia (ProAD), 37 were NI-positive, 29 were (11)C-PiB-positive, and 27 who were both NI- and (11C-PiB-positive were categorized as having 'ProAD dementia with a high level of evidence of the AD pathophysiological process'. Among 20 patients with possible AD dementia (PosAD), 17 were NI-positive, and six who were both NI- and (11)C-PiB-positive were categorized as having 'PosAD with evidence of the AD pathophysiological process'. Among 25 patients with MCI, 18 were NI-positive, 13 were (11)C-PiB-positive, and 10 who were both NI- and (11)C-PiB-positive were categorized as having 'MCI due to AD-high likelihood'. CONCLUSIONS: Diagnostic concordance between clinical criteria and research criteria may not be high in this study. (11)C-PiB PET may be of value in making the diagnosis of dementia and MCI in cases with high diagnostic uncertainty.

Concordance between (99m)Tc-ECD SPECT and 18F-FDG PET interpretations in patients with cognitive disorders diagnosed according to NIA-AA criteria.

OBJECTIVES: The purpose of this study was to clarify the concordance of diagnostic abilities and interobserver agreement between 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) and brain perfusion single photon-emission computed tomography (SPECT) in patients with Alzheimer's disease (AD) who were diagnosed according to the research criteria of the National Institute of Aging-Alzheimer's Association Workshop. METHODS: Fifty-five patients with "AD and mild cognitive impairment (MCI)" (n = 40) and "non-AD" (n = 15) were evaluated with 18F-FDG PET and (99m)Tc-ethyl cysteinate dimer (ECD) SPECT during an 8-week period. Three radiologists independently graded the regional uptake in the frontal, temporal, parietal, and occipital lobes as well as the precuneus/posterior cingulate cortex in both images. Kappa values were used to determine the interobserver reliability regarding regional uptake. RESULTS: The regions with better interobserver reliability between 18F-FDG PET and (99m)Tc-ECD SPECT were the frontal, parietal, and temporal lobes. The (99m)Tc-ECD SPECT agreement in the occipital lobes was not significant. The frontal, temporal, and parietal lobes showed good correlations between 18F-FDG PET and (99m)Tc-ECD SPECT in the degree of uptake, but the occipital lobe and precuneus/posterior cingulate cortex did not show good correlations. The diagnostic accuracy rates of "AD and MCI" ranged from 60% to 70% in both of the techniques. CONCLUSIONS: The degree of uptake on 18F-FDG PET and (99m)Tc-ECD SPECT showed significant correlations in the frontal, temporal, and parietal lobes. The diagnostic abilities of 18F-FDG PET and (99m)Tc-ECD SPECT for "AD and MCI," when diagnosed according to the National Institute of Aging-Alzheimer's Association Workshop criteria, were nearly identical.

Cerebral small-vessel disease protein HTRA1 controls the amount of TGF-ß1 via cleavage of proTGF-ß1.

Cerebral small-vessel disease is a common disorder in elderly populations; however, its molecular basis is not well understood. We recently demonstrated that mutations in the high-temperature requirement A (HTRA) serine peptidase 1 (HTRA1) gene cause a hereditary cerebral small-vessel disease, cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL). HTRA1 belongs to the HTRA protein family, whose members have dual activities as chaperones and serine proteases and also repress transforming growth factor-ß (TGF-ß) family signaling. We demonstrated that CARASIL-associated mutant HTRA1s decrease protease activity and fail to decrease TGF-ß family signaling. However, the precise molecular mechanism for decreasing the signaling remains unknown. Here we show that increased expression of ED-A fibronectin is limited to cerebral small arteries and is not observed in coronary, renal arterial or aortic walls in patients with CARASIL. Using a cell-mixing assay, we found that HTRA1 decreases TGF-ß1 signaling triggered by proTGF-ß1 in the intracellular space. HTRA1 binds and cleaves the pro-domain of proTGF-ß1 in the endoplasmic reticulum (ER), and cleaved proTGF-ß1 is degraded by ER-associated degradation. Consequently, the amount of mature TGF-ß1 is reduced. These results establish a novel mechanism for regulating the amount of TGF-ß1, specifically, the intracellular cleavage of proTGF-ß1 in the ER.

Association of HTRA1 mutations and familial ischemic cerebral small-vessel disease.

BACKGROUND: The genetic cause of cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL), which is characterized by ischemic, nonhypertensive, cerebral small-vessel disease with associated alopecia and spondylosis, is unclear. METHODS: In five families with CARASIL, we carried out linkage analysis, fine mapping of the region implicated in the disease, and sequence analysis of a candidate gene. We also conducted functional analysis of wild-type and mutant gene products and measured the signaling by members of the transforming growth factor beta (TGF-beta) family and gene and protein expression in the small arteries in the cerebrum of two patients with CARASIL. RESULTS: We found linkage of the disease to the 2.4-Mb region on chromosome 10q, which contains the HtrA serine protease 1 (HTRA1) gene. HTRA1 is a serine protease that represses signaling by TGF-beta family members. Sequence analysis revealed two nonsense mutations and two missense mutations in HTRA1. The missense mutations and one of the nonsense mutations resulted in protein products that had comparatively low levels of protease activity and did not repress signaling by the TGF-beta family. The other nonsense mutation resulted in the loss of HTRA1 protein by nonsense-mediated decay of messenger RNA. Immunohistochemical analysis of the cerebral small arteries in affected persons showed increased expression of the extra domain-A region of fibronectin and versican in the thickened tunica intima and of TGF-beta1 in the tunica media. CONCLUSIONS: CARASIL is associated with mutations in the HTRA1 gene. Our findings indicate a link between repressed inhibition of signaling by the TGF-beta family and ischemic cerebral small-vessel disease, alopecia, and spondylosis.

Relationship between apathy and diffusion tensor imaging metrics of the brain in Alzheimer's disease.

OBJECTIVE: Alzheimer's disease (AD) research has largely concentrated on the study of cognitive decline, but the associated behavioral and neuropsychiatric symptoms are of equal importance in the clinical profile of the disease. Apathy is the most common neuropsychiatric manifestation in AD. Clinical, multimodal neuroimaging studies and pathologic studies of apathy in AD have suggested an association with frontal dysfunction but without a definitive localization. In this study, we examined the association between apathy and white matter integrity using diffusion tensor imaging (DTI). METHODS: Twenty-one AD patients underwent DTI and neuropsychiatric and cognitive assessments. All fractional anisotropy (FA) maps were normalized to the standard space, and the association between the apathy scale and DTI metrics were evaluated voxel basically. RESULTS: Statistical parametric mapping analysis showed that there were statistically negative correlations between the apathy scale and FA values in the right anterior cingulate, right thalamus, and bilateral parietal regions using age, Mini-Mental State Examination score and sex as nuisance variables. CONCLUSIONS: Apathy in AD is associated with impaired white matter integrity in the anterior cingulate and medial thalamus. These results reinforce the confluence of evidence from other investigational modalities in implicating limbic dysfunction and related neuronal circuits in the neurobiology of apathy in AD.

Phosphorylated Syk expression is enhanced in Nasu-Hakola disease brains.

Nasu-Hakola disease (NHD) is a rare autosomal recessive disorder, characterized by progressive presenile dementia and formation of multifocal bone cysts, caused by a loss-of-function mutation of DNAX-activation protein 12 (DAP12) or triggering receptor expressed on myeloid cells 2 (TREM2). TREM2 and DAP12 constitute a receptor/adaptor complex on myeloid cells. The post-receptor signals are transmitted via rapid phosphorylation of the immunoreceptor tyrosine-based activating motif (ITAM) of DAP12, mediated by Src protein tyrosine kinases, followed by binding of phosphorylated ITAM to Src homology 2 (SH2) domains of spleen tyrosine kinase (Syk), resulting in autophosphorylation of the activation loop of Syk. To elucidate the molecular mechanism underlying the pathogenesis of NHD, we investigated Syk expression and activation in the frontal cortex and the hippocampus of three NHD and eight control brains by immunohistochemistry. In NHD brains, the majority of neurons expressed intense immunoreactivities for Syk and Y525/Y526-phosphorylated Syk (pSyk) chiefly located in the cytoplasm, while more limited populations of neurons expressed Src. The levels of pSyk expression were elevated significantly in NHD brains compared with control brains. In both NHD and control brains, substantial populations of microglia and macrophages expressed pSyk, while the great majority of reactive astrocytes and myelinating oligodendrocytes did not express pSyk, Syk or Src. These observations indicate that neuronal expression of pSyk was greatly enhanced in the cerebral cortex and the hippocampus of NHD brains, possibly via non-TREM2/DAP12 signaling pathways involved in Syk activation.

Immunohistochemical characterization of microglia in Nasu-Hakola disease brains.

Nasu-Hakola disease (NHD) is a rare autosomal recessive disorder, characterized by progressive presenile dementia and formation of multifocal bone cysts, caused by genetic mutations of DNAX-activation protein 12 (DAP12) or triggering receptor expressed on myeloid cells 2 (TREM2). TREM2 and DAP12 constitute a receptor/adapter signaling complex expressed on osteoclasts, dendritic cells (DC), macrophages and microglia. Previous studies using knockout mice and mouse brain cell cultures suggest that a loss-of-function of DAP12/TREM2 in microglia plays a central role in the neuropathological manifestation of NHD. However, there exist no immunohistochemical studies that focus attention on microglia in NHD brains. To elucidate a role of microglia in the pathogenesis of NHD, we searched NHD-specific biomarkers and characterized their expression on microglia in NHD brains. Here, we identified allograft inflammatory factor 1 (AIF1, Iba1) and sialic acid binding Ig-like lectin 1 (SIGLEC1) as putative NHD-specific biomarkers by bioinformatics analysis of microarray data of NHD DC. We studied three NHD and eight control brains by immunohistochemistry with a panel of 16 antibodies, including those against Iba1 and SIGLEC1. We verified the absence of DAP12 expression in NHD brains and the expression of DAP12 immunoreactivity on ramified microglia in control brains. Unexpectedly, TREM2 was not expressed on microglia but expressed on a small subset of intravascular monocytes/macrophages in control and NHD brains. In the cortex of NHD brains, we identified accumulation of numerous Iba1-positive microglia to an extent similar to control brains, while SIGLEC1 was undetectable on microglia in all the brains examined. These observations indicate that human microglia in brain tissues do not express TREM2 and DAP12-deficient microglia are preserved in NHD brains, suggesting that the loss of DAP2/TREM2 function in microglia might not be primarily responsible for the neuropathological phenotype of NHD.

TDP-43 dimerizes in human cells in culture.

TAR DNA-binding protein-43 (TDP-43) is a 43-kDa nuclear protein involved in regulation of gene expression. Abnormally, phosphorylated, ubiquitinated, and aggregated TDP-43 constitute a principal component of neuronal and glial cytoplasmic and nuclear inclusions in the brains of frontotemporal lobar degeneration with ubiquitin-positive inclusions (FTLD-U) and amyotrophic lateral sclerosis (ALS), although the molecular mechanism that triggers aggregate formation remains unknown. By Western blot analysis using anti-TDP-43 antibodies, we identified a band with an apparent molecular mass of 86-kDa in HEK293, HeLa, and SK-N-SH cells in culture. It was labeled with both N-terminal-specific and C-terminal-specific TDP-43 antibodies, enriched in the cytosolic fraction, and the expression levels were reduced by TDP-43 siRNA but unaltered by treatment with MG-132 or by expression of ubiqulin-1 or casein kinase-1. By immunoprecipitation analysis, we found the interaction between the endogenous full-length TDP-43 and the exogenous Flag-tagged TDP-43, and identified the N-terminal half of TDP-43 spanning amino acid residues 3-183 as an intermolecular interaction domain. When the tagged 86-kDa tandemly connected dimer of TDP-43 was overexpressed in HEK293, it was sequestered in the cytoplasm and promoted an accumulation of high-molecular-mass TDP-43-immunoreactive proteins. Furthermore, the 86-kDa band was identified in the immunoblot of human brain tissues, including those of ALS. These results suggest that the 86-kDa band represents dimerized TDP-43 expressed constitutively in normal cells under physiological conditions.

Protein microarray analysis identifies cyclic nucleotide phosphodiesterase as an interactor of Nogo-A.

Nogo-A, a neurite outgrowth inhibitor, is expressed exclusively on oligodendrocytes and neurons in the CNS. The central domain of Amino-Nogo spanning amino acids 567-748 in the human Nogo-A designated NIG, mediates persistent inhibition of axonal outgrowth and induces growth cone collapse by signaling through an as yet unidentified NIG receptor. We identified 82 NIG-interacting proteins by screening a high-density human protein microarray composed of 5000 proteins with a recombinant NIG protein as a probe. Following an intensive database search, we selected 12 neuron/oligodendrocyte-associated NIG interactors. Among them, we verified the molecular interaction of NIG with 2', 3'-cyclic nucleotide 3'-phosphodiesterase (CNP), a cell type-specific marker of oligodendrocytes, by immunoprecipitation and cell imaging analysis. Although CNP located chiefly in the cytoplasm of oligodendrocytes might not serve as a cell-surface NIG receptor, it could act as a conformational stabilizer for the intrinsically unstructured large segment of Amino-Nogo.

Potential pathophysiological role of D-amino acid oxidase in schizophrenia: immunohistochemical and in situ hybridization study of the expression in human and rat brain.

D-Amino acid oxidase (DAO) is a peroxisomal flavoenzyme that catalyzes oxidative deamination of a wide range of D-amino acids. Among the possible substrates of DAO in vivo, D-serine is proposed to be a neuromodulator of the N-methyl-D-aspartate (NMDA) type glutamate receptor. The gene for DAO was reported to be associated with schizophrenia. Since DAO is expected to be one of the key enzymes in the regulation of NMDA neurotransmission, the modulation of the enzyme activity is expected to be therapeutical for neuronal disorders. In search of the pathophysiological role of DAO, we analyzed the distribution of DAO mRNA and protein in the rat and human brain. In rat, the distribution of DAO mRNA was newly detected in choroid plexus (CP) epithelial cells in addition to glial cells of pons, medulla oblongata, and especially Bergmann glia of cerebellum. Moreover, to investigate how DAO expression level is altered in schizophrenia, we performed immunohistochemistry in the human brain. In agreement with the results in the rat brain, the immunoreactivity for DAO was detected in glial cells of rhombencephalon and in CP. Furthermore, higher level of DAO expression was observed in schizophrenic CP epithelial cells than that in non-schizophrenic cases. These results suggest that an increase in DAO expression in parts of the brain is involved in aberrant D-amino acid metabolism. In particular, gene expression of DAO in CP suggests that DAO may regulate D-amino acid concentration by modulating the cerebrospinal fluid and may be regarded as a potential therapeutic target for schizophrenia.

Close association of water channel AQP1 with amyloid-beta deposition in Alzheimer disease brains.

Aquaporin-1 (AQP1), a membrane water channel protein, is expressed exclusively in the choroid plexus epithelium in the central nervous system under physiological conditions. However, AQP1 expression is enhanced in reactive astrocytes, accumulating in brain lesions of Creutzfeldt-Jakob disease and multiple sclerosis, suggesting a role of AQP1-expressing astrocytes in brain water homeostasis under pathological conditions. To clarify a pathological implication of AQP1 in Alzheimer disease (AD), we investigated the possible relationship between amyloid-beta (Abeta) deposition and astrocytic AQP1 expression in the motor cortex and hippocampus of 11 AD patients and 16 age-matched other neurological disease cases. In all cases, AQP1 was expressed exclusively in a subpopulation of multipolar fibrillary astrocytes. The great majority of AQP1-expressing astrocytes were located either on the top of or in close proximity to Abeta plaques in AD brains but not in non-AD cases, whereas those independent of Abeta deposition were found predominantly in non-AD brains. By Western blot, cultured human astrocytes constitutively expressed AQP1, and the levels of AQP1 protein expression were not affected by exposure to Abeta(1-42) peptide, but were elevated by hypertonic sodium chloride. By immunoprecipitation, the C-terminal fragment-beta (CTFbeta) of amyloid precursor protein interacted with the N-terminal half of AQP1 spanning the transmembrane helices H1, H2 and H3. These observations suggest the possible association of astrocytic AQP1 with Abeta deposition in AD brains.

Plaque-type deposition of prion protein in the damaged white matter of sporadic Creutzfeldt-Jakob disease MM1 patients.

Plaque-type deposition of prion protein (PrP) in the brain has been extremely rare in sporadic Creutzfeldt-Jakob disease patients with methionine homozygosity at polymorphic codon 129 of the PrP gene and type 1 abnormal isoform of PrP (sCJD-MM1). Here we report three sCJD-MM1 patients who showed prominent PrP-positive amyloid plaques in the cerebral and cerebellar white matter. All three patients showed clinical courses of long duration (2 years < or =), particularly at the end-stage. The white matter of these patients was severely damaged because of the prolonged disease duration. Furthermore, Alzheimer's amyloid precursor protein, which accumulates within the axonal swellings under pathological conditions, co-accumulated with the PrP-amyloid plaques. These findings suggest that the axonal damage reflecting the prolonged disease duration causes the deposition of PrP-amyloid plaques in the white matter. The present study shows that PrP-amyloid plaques can occur in the white matter of sCJD-MM1 cases.

Perceptual change in response to a bistable picture increases neuromagnetic beta-band activities.

The purpose of the present study was to examine by whole-head magnetoencephalography (MEG) brain oscillatory responses related to visual perceptual change of short-term duration in the absence of morphologic change. Twenty healthy volunteers participated in this study. We used three pictures: a bistable picture with ambiguous contours that could represent two different objects ('target') and two preceding pictures that were clear representations of either object ('face' or 'saxophone'). Two types of stimulus conditions were created, the 'face-target' (F-T) condition and the 'saxophone-target' (S-T) condition, and data acquisition was performed mainly during presentation of the 'target' picture. Time-frequency analysis was performed by means of fast Fourier transform. All subjects reported that they perceived the 'target' picture predominantly as a 'face' regardless of the preceding picture. We suspect that perceptual change occurred more frequently in the S-T condition than in the F-T condition. We found significantly greater synchronization in the beta (14-30-Hz) frequency band, ranging from 250 to 450ms predominantly over the occipital and parietal regions, after stimulus alternation for the S-T condition than for the F-T condition. Results of the present study show that the change in beta-band activity reflects a change in visual perception.

Localization of CKII beta subunits in Lewy bodies of Parkinson's disease.

We reported previously that phosphorylation by casein kinase II (CKII) regulates the interaction between alpha-synuclein and its binding partner synphilin-1, and that both CKII alpha and beta subunits co-localize with alpha-synuclein in cytoplasmic inclusions in transfected cells. In this study, we extended these observations to the brains of patients with Parkinson's disease (PD) and examined whether CKII subunits are present in Lewy bodies. Immunohistochemical studies on PD brains harboring Lewy bodies revealed a positive stain for CKII beta but not for CKII alpha. In addition, CKII beta subunits co-localized with alpha-synuclein in most Lewy bodies. These findings suggest that CKII beta subunits may play a role in the formation of intracytoplasmic inclusions in human alpha-synucleinopathies either through phosphorylation events or through a separate mechanism linked to the beta subunit itself.

Autosomal dominant leukoencephalopathy with mild clinical symptoms due to cerebrovascular dysfunctions: a new disease entity?

A family with cerebrovascular dysfunctions and extensive white matter lesions was presented. The proband had suffered migraine. His brother showed syncopal episodes and migraine. His mother also suffered severe migraine with aura, and had transient hemiparesis during pregnancy. Their brain MRIs, being quite similar to each other, revealed diffuse bilateral deep white matter lesions, with no changes in serial follow-up. His grandmother showed similar white matter changes on CT, consistent with autosomal dominant inheritance. Lesions were considered to be due to chronic vasogenic edema based upon increased apparent diffusion coefficient (ADC) values on diffusion-weighted imaging, normal spectrum ratio of metabolites on (1)H MR spectroscopy, and decreased regional cerebral blood flows on single-photon emission CT (SPECT). A deficiency of genetically determined factors contributing to the autoregulation of small blood vessels might possibly lead to both clinical symptoms and white matter lesions through the breakdown of the blood-brain barrier and resultant vasogenic edema. Although cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) was suspected, neither NOTCH3 mutation nor granular osmiphilic material (GOM) in the arteriole walls were detected. Further accumulation of similar cases is necessary to establish the possibility of a new familial leukoencephalopathy.