Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Megumi Yamada is active.

Publication


Featured researches published by Megumi Yamada.


Journal of the Neurological Sciences | 2011

Patterns of levels of biological metals in CSF differ among neurodegenerative diseases

Isao Hozumi; Tatsuya Hasegawa; Akiko Honda; Kazuhiro Ozawa; Y.K. Hayashi; Kazunori Hashimoto; Megumi Yamada; Akihiro Koumura; Takeo Sakurai; Akio Kimura; Yuji Tanaka; Masahiko Satoh; Takashi Inuzuka

We measured the levels of some biological metals: copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), and zinc (Zn) in the cerebrospinal fluid (CSF) in patients with neurodegenerative diseases (52 patients with amyotrophic lateral sclerosis (ALS)), 21 patients with Alzheimers disease (AD), and 20 patients with Parkinsons disease (PD) by inductively coupled plasma mass spectrometry (ICP-MS). The diagnoses were additionally supported by neuroimaging techniques for AD and PD. In ALS, the levels of Mg (p<0.01 significant difference), Fe, Cu (p<0.05), and Zn (p<0.10) in CSF were higher than those in controls. Some patients showed very high levels of Cu and Zn before the critical deterioration of the disease. In AD, the levels of Cu and Zn in CSF were significantly higher in patients with late-onset AD (p<0.01). In PD, we found significantly increased levels of especially Cu and Zn in particular (p<0.01) and Mn (p<0.05) in CSF. A multiple comparison test suggested that the increased level of Mg in ALS and that of Mn in PD were the pathognomonic features. These findings suggest that Cu and Zn in particular play important roles in the onset and/or progression of ALS, AD, and PD. Therefore, Cu-chelating agents and modulators of Cu and Zn such as metallothionein (MT) can be new candidates for the treatment of ALS, AD, and PD.


Neurology | 2014

Evaluation of SLC20A2 mutations that cause idiopathic basal ganglia calcification in Japan

Megumi Yamada; Masaki Tanaka; Mari Takagi; Seiju Kobayashi; Yoshiharu Taguchi; Shutaro Takashima; Kortaro Tanaka; Tetsuo Touge; Hiroyuki Hatsuta; Shigeo Murayama; Yuichi Hayashi; Masayuki Kaneko; Hiroyuki Ishiura; Jun Mitsui; Naoki Atsuta; Gen Sobue; Nobuyuki Shimozawa; Takashi Inuzuka; Shoji Tsuji; Isao Hozumi

Objective: To investigate the clinical, genetic, and neuroradiologic presentations of idiopathic basal ganglia calcification (IBGC) in a nationwide study in Japan. Methods: We documented clinical and neuroimaging data of a total of 69 subjects including 23 subjects from 10 families and 46 subjects in sporadic cases of IBGC in Japan. Mutational analysis of SLC20A2 was performed. Results: Six new mutations in SLC20A2 were found in patients with IBGC: 4 missense mutations, 1 nonsense mutation, and 1 frameshift mutation. Four of them were familial cases and 2 were sporadic cases in our survey. The frequency of families with mutations in SLC20A2 in Japan was 50%, which was as high as in a previous report on other regions. The clinical features varied widely among the patients with SLC20A2 mutations. However, 2 distinct families have the same mutation of S637R in SLC20A2 and they have similar characteristics in the clinical course, symptoms, neurologic findings, and neuroimaging. In our study, all the patients with SLC20A2 mutations showed calcification. In familial cases, there were symptomatic and asymptomatic patients in the same family. Conclusion: SLC20A2 mutations are a major cause of familial IBGC in Japan. The members in the families with the same mutation had similar patterns of calcification in the brain and the affected members showed similar clinical manifestations.


Geriatrics & Gerontology International | 2013

High frequency of calcification in basal ganglia on brain computed tomography images in Japanese older adults

Megumi Yamada; Takahiko Asano; Kouichirou Okamoto; Y.K. Hayashi; Masayuki Kanematsu; Hiroaki Hoshi; Yasuhisa Akaiwa; Takayoshi Shimohata; Masatoyo Nishizawa; Takashi Inuzuka; Isao Hozumi

To investigate the frequency of calcification in the basal ganglia and the dentate nuclei in the cerebellum, and compare the difference in age and area, we examined the brain computed tomography (CT) images of all patients in two representative university hospitals in Japan.


Case Reports in Neurology | 2010

High Levels of Copper, Zinc, Iron and Magnesium, but not Calcium, in the Cerebrospinal Fluid of Patients with Fahr's Disease.

Isao Hozumi; Akihiro Kohmura; Akio Kimura; Tatsuya Hasegawa; Akiko Honda; Y.K. Hayashi; Kazunori Hashimoto; Megumi Yamada; Takeo Sakurai; Yuji Tanaka; Masahiko Satoh; Takashi Inuzuka

Patients with marked calcification of the basal ganglia and cerebellum have traditionally been referred to as having Fahr’s disease, but the nomenclature has been criticized for including heterogeneous etiology. We describe 3 patients with idiopathic bilateral striatopallidodentate calcinosis (IBSPDC). The patients were a 24-year-old man with mental deterioration, a 57-year-old man with parkinsonism and dementia, and a 76-year-old woman with dementia and mild parkinsonism. The former 2 patients showed severe calcification of the basal ganglia and cerebellum, and the latter patient showed severe calcification of the cerebellum. We found significantly increased levels of copper (Cu), zinc (Zn), iron (Fe) and magnesium (Mg), using inductively coupled plasma mass spectrometry in the CSF of all these 3 patients. The increased levels of Cu, Zn, Fe and Mg reflect the involvement of metabolism of several metals and/or metal-binding proteins during the progression of IBSPDC. More numerous patients with IBSPDC should be examined in other races to clarify the common mechanism of the disease and to investigate the specific treatment.


Neurology | 2010

Antibodies in patients with neuropsychiatric systemic lupus erythematosus

Akio Kimura; Y. Kanoh; Takeo Sakurai; Akihiro Koumura; Megumi Yamada; Y.K. Hayashi; Yuji Tanaka; Isao Hozumi; Masao Takemura; Mitsuru Seishima; Takashi Inuzuka

Objective: To investigate a target for antibodies in patients with neuropsychiatric systemic lupus erythematosus (NPSLE). Background: Pathogenesis of NPSLE may be related to autoantibody-mediated neural dysfunction, vasculopathy, and coagulopathy. However, very few autoantibodies are sensitive and specific to NPSLE because the neuropsychiatric syndromes associated with SLE are diverse in cause and presentation. Methods: We identified antibodies against brain antigens in the sera of 7 patients with NPSLE and 12 healthy controls by 2-dimensional electrophoresis, followed by Western blotting and liquid chromatography–tandem mass spectrometry (LC-MS/MS), using rat brain proteins as the antigen source. Results: Six antibodies were detected in patients with NPSLE. One of these 6 antibodies was found in antibodies against Rab guanosine diphosphate dissociation inhibitor α (αGDI) (which is specifically abundant in neurons and regulates synaptic vesicle exocytosis) in patients with NPSLE with psychosis. We tested more samples by 1-dimensional immunoblotting of human recombinant αGDI. Positivity of the anti-αGDI antibody was significantly higher in patients with NPSLE with psychosis (80%, 4 of 5) than in patients with NPSLE without psychosis (0%, 0 of 13), patients with systemic lupus erythematosus without neuropsychiatric symptoms (5.3%, 1 of 19), patients with multiple sclerosis (0%, 0 of 12), patients with infectious meningoencephalitis (0%, 0 of 13), patients with polyneuropathy (0%, 0 of 10), patients with psychotic syndromes (0%, 0 of 10), and healthy controls (0%, 0 of 12). Conclusions: We propose that the anti–Rab guanosine diphosphate dissociation inhibitor α antibody is a candidate for further exploration as diagnostic marker of psychosis associated with neuropsychiatric systemic lupus erythematosus.


Journal of Neurology | 2013

Cardiac sympathetic function in the patients with amyotrophic lateral sclerosis: analysis using cardiac [123I] MIBG scintigraphy

Yuji Tanaka; Megumi Yamada; Akihiro Koumura; Takeo Sakurai; Yuichi Hayashi; Akio Kimura; Isao Hozumi; Takashi Inuzuka

Amyotrophic lateral sclerosis (ALS), which is the most serious form of degenerative motor neuron disease in adults, is characterized by upper and lower motor neuron degeneration, skeletal muscle atrophy, paralysis, and death. Some patients with respiratory-dependent ALS die of sudden cardiac arrest or anoxic encephalopathy following circulatory collapse, which may be associated with sympathetic hyperactivity. Cardiac [123I] MIBG scintigraphy is a diagnostic method of cardiac sympathetic function. However, few reports have addressed cardiac sympathetic function in ALS patients using this technique. We investigated cardiac sympathetic function in 63 ALS patients and 10 healthy volunteers using cardiac [123I] metaiodobenzylguanidine (MIBG) scintigraphy [heart/mediastinum ratio (H/M ratio) in the early phase and washout ratio (WR)] at the time of diagnosis. The WR of cardiac [123I] MIBG scintigraphy, which indicates cardiac sympathetic activity, was significantly increased in ALS patients compared with controls. ALS patients with an increased WR exhibited a significantly higher progression rate compared with those with normal WR. Moreover, the survival of ALS patients with increased WR was significantly decreased compared with those with normal WR. These results suggested that some patients with ALS have sympathetic hyperactivity at the time of diagnosis. ALS patients may suffer from chronic cardiac sympathetic hyperactivity, which is associated with sudden cardiac death and stress induced cardiomyopathy. Increased WR in cardiac [123I] MIBG scintigraphy may be a predictive factor in ALS patients.


Journal of Neuroimmunology | 2010

High prevalence of autoantibodies against phosphoglycerate mutase 1 in patients with autoimmune central nervous system diseases.

Akio Kimura; Takeo Sakurai; Akihiro Koumura; Megumi Yamada; Y.K. Hayashi; Yuji Tanaka; Isao Hozumi; Ryo Tanaka; Masao Takemura; Mitsuru Seishima; Takashi Inuzuka

We identified the autoantibody against phosphoglycerate mutase 1 (PGAM1), which is a glycolytic enzyme, in sera from multiple sclerosis (MS) patients by proteomics-based analysis. We further searched this autoantibody in sera from patients with other neurological diseases. The prevalence of the anti-PGAM1 antibody is much higher in patients with MS and neuromyelitis optica (NMO) than in those with other neurological diseases and in healthy controls. It was reported that the anti-PGAM1 antibody is frequently detected in patients with autoimmune hepatitis (AIH). Results of our study suggest that the anti-PGAM1 antibody is not only a marker of AIH but also a nonspecific marker of central nervous system autoimmune diseases.


Journal of Neuroimmunology | 2011

Identification of antibodies as biological markers in serum from multiple sclerosis patients by immunoproteomic approach

Takeo Sakurai; Akio Kimura; Megumi Yamada; Akihiro Koumura; Y.K. Hayashi; Yuji Tanaka; Isao Hozumi; Takashi Inuzuka

We identified the antibody against mitochondrial heat shock protein 70 (mtHSP70) in serum from multiple sclerosis (MS) patients by proteomics-based analysis. The prevalence of the anti-mtHSP70 antibody is significantly higher in serum from MS patients than in serum from Parkinson disease patients, multiple cerebral infarction patients, infectious meningoencephalitis patients, and healthy controls (HCs) (68% sensitivity; 74% specificity). We studied the clinical features and magnetic resonance imaging findings of MS patients with the anti-mtHSP70 antibody. As a result, there were no significant differences between the anti-mtHSP70-antibody-positive and -negative MS patients. Additionally, in our comprehensive analysis of the prevalence of both the anti-mtHSP70 antibody and the anti-phosphoglycerate mutase 1 (PGAM1) antibody, which was previously reported by us to also show a higher prevalence in serum from MS patients, the positivity rates of both these antibodies were significantly higher in serum from MS patients than in serum from patients with other neurological diseases and from HCs; moreover, the specificity of this combination assay was higher than that of the assay of only one antibody (57% sensitivity; 93% specificity). Results of our study suggest that not only the anti-PGAM1 antibody but also the anti-mtHSP70 antibody is good diagnostic markers of MS and the combination of both these antibodies is useful for a more specific diagnosis of MS.


Geriatrics & Gerontology International | 2017

Reduction in the numbers of drugs administered to elderly in-patients with polypharmacy by a multidisciplinary review of medication using electronic medical records.

Yuichi Hayashi; Ayumi Godai; Megumi Yamada; Nobuaki Yoshikura; Naoko Harada; Akihiro Koumura; Akio Kimura; Shinji Okayasu; Yasuko Matsuno; Yasutomi Kinosada; Yoshinori Itoh; Takashi Inuzuka

Polypharmacy is a major problem for elderly patients in developed countries. We investigated whether a multidisciplinary medication review using electronic medical records could reduce the number of drugs administered to elderly patients receiving polypharmacy.


Journal of Stroke & Cerebrovascular Diseases | 2012

Elevated Anti-Heat Shock Protein 60 Antibody Titer is Related to White Matter Hyperintensities

Akio Kimura; Takeo Sakurai; Megumi Yamada; Akihiro Koumura; Yuichi Hayashi; Yuji Tanaka; Isao Hozumi; Masao Takemura; Mitsuru Seishima; Takashi Inuzuka

BACKGROUND There are many reports that the antibody against heat shock protein 60 (Hsp60) is present in most patients with coronary artery disease and atherosclerosis, and that its titer correlates with disease severity. However, few reports have described the association between anti-Hsp60 antibody and cerebrovascular disease. METHODS We determined the anti-Hsp60 antibody titer in patients with neurologic diseases and healthy subjects using enzyme-linked immunosorbent assay (ELISA) and evaluated their findings of brain magnetic resonance imaging (MRI) of the white matter. White matter hyperintensities (WMHs) on T2-weighted and fluid-attenuated inversion recovery (FLAIR) images were classified into 2 categories: periventricular hyperintensity (PVH) and deep white matter hyperintensity (DWMH). The lesions in each category were then divided into 4 grades (grades 0-3) according to the Fazekas rating scale. RESULTS There were no significant differences in the titer between patients with neurologic diseases and healthy subjects. The mean grade of DWMHs (mean ± SD, 1.56 ± 0.70) was significantly higher in 18 subjects in the high-titer group (≥39.8 ng/mL; mean titer + 2 SD in sera from 23 healthy subjects) than in 86 subjects (mean ± SD, 0.09 ± 0.76) in the normal-titer group (<39.8 ng/mL; P < .003). The mean grade of PVHs (mean ± SD, 1.50 ± 0.71) was also significantly higher in the high-titer group than in the normal-titer group (mean ± SD, 1.17 ± 0.62; P < .02). CONCLUSIONS A significant correlation was noted between anti-Hsp60 antibody titer and the severity of WMHs on brain MR images. We suggest that an elevated titer of the anti-Hsp60 antibody could be a risk factor for cerebral small-vessel disease.

Collaboration


Dive into the Megumi Yamada's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Isao Hozumi

Gifu Pharmaceutical University

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge