Yurika Numata

National Center of Neurology and Psychiatry, Кодаиры, Tōkyō, Japan

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Publications (12)27.53 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Neuromyelitis optica (NMO) is an inflammatory demyelinating disease with a poor prognosis that is characterized by inflammatory optic neuritis and myelitis. Although it is commonly misdiagnosed as multiple sclerosis (MS), distinguishing NMO from MS is important, as therapeutic approaches approved for MS are ineffective in patients with NMO. The aquaporin-4 (AQP4) antibody is a pathogenic and diagnostic biomarker for NMO. We report an AQP4 antibody-positive 9-year-old female with intractable hiccups and nausea (IHN). Brain imaging revealed lesions in the brainstem, thalami, and hypothalamus. Nevertheless, she had no clinical or radiological signs referable to the optic nerve or spinal cord. We propose that in patients with characteristic IHN associated lesions involving the brainstem or hypothalamus, measurement of AQP4 antibody should be considered for selectivity of treatment, even if the patient has no optic nerve or spinal cord lesions.
    Brain & development 04/2014; · 1.74 Impact Factor
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    ABSTRACT: To determine the epidemiological, clinical, and genetic characteristics of congenital hypomyelinating leukodystrophies, including Pelizaeus-Merzbacher disease (PMD), we conducted a nationwide epidemiological survey in Japan. A two-step survey targeting all medical institutions specializing in pediatric neurology and childhood disability (919 institutes) in Japan was performed. Detailed information was collected for 101 patients (86 males and 15 females) with congenital hypomyelinating leukodystrophies. The prevalence of congenital hypomyelinating disorders was 0.78 per 100,000 people (0-19 years old), and the incidence was 1.40 per 100,000 live births. Molecular testing was performed in 75 % of patients, and PLP1 gene abnormalities were observed in 62 %. The incidence of PMD with PLP1 mutations was estimated to be 1.45 per 100,000 male live births and that for congenital hypomyelinating disorders with unknown cause to be 0.41 per 100,000 live births. Patients with PLP1 mutations showed a higher proportion of nystagmus and hypotonia, both of which tend to disappear over time. Our results constitute the first nationwide survey of congenital hypomyelinating disorders, and provide the epidemiological, clinical, and genetic landscapes of these disorders.
    Journal of Neurology 02/2014; · 3.58 Impact Factor
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    ABSTRACT: Pelizaeus-Merzbacher disease (PMD) is a hypomyelinating disorder caused by the duplication and missense mutations of the proteolipid protein 1 (PLP1) gene. PLP1 missense proteins accumulate in the endoplasmic reticulum (ER) of premature oligodendrocytes and induce severe ER stress followed by apoptosis of the cells. Here, we demonstrate that an anti-malaria drug, chloroquine, decreases the amount of an ER-resident mutant PLP1 containing an alanine-243 to valine (A243V) substitution, which induces severe PMD in human. By preventing mutant PLP1 translation through enhancing the phosphorylation of eukaryotic initiation factor 2 alpha, chloroquine ameliorated the ER stress induced by the mutant protein in HeLa cells. Chroloquine also attenuated ER stress in the primary oligodendrocytes obtained from myelin synthesis deficit (msd) mice, which carry the same PLP1 mutation. In the spinal cords of msd mice, chloroquine inhibited ER stress and upregulated the expression of marker genes of mature oligodendrocytes. Chloroquine-mediated attenuation of ER stress was observed in HeLa cells treated with tunicamycin, an N-glycosylation inhibitor, but not with thapsigargin, a sarco/ER Ca(2+)ATPase inhibitor, which confirms its efficacy against ER stress caused by nascent proteins. These findings indicate that chloroquine is an ER stress attenuator with potential use in treating PMD and possibly other ER stress-related diseases.
    Experimental Biology and Medicine 02/2014; · 2.80 Impact Factor
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    ABSTRACT: In addition to the typical infantile spasm symptoms, several other symptoms, such as eye movements, have been reported to be associated with infantile spasms, although the relationship between the typical spasms and these other events is not fully understood. Here we present a case with West syndrome. We observed the appearance of periodic eye movements followed by the onset of typical spasms and the appearance/disappearance of periodic eye movements during withdrawal/increases of vigabatrin. We believe that the case strongly supports the notion that periodic eye movements and typical spasms represent a spectrum of symptoms related to the same phenomenon of West syndrome.
    Journal of child neurology 05/2013; · 1.59 Impact Factor
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    ABSTRACT: Missense mutations in the proteolipid protein 1 (PLP1) gene cause a wide spectrum of hypomyelinating disorders, from mild spastic paraplegia type 2 to severe Pelizaeus-Merzbacher disease (PMD). Mutant PLP1 accumulates in the endoplasmic reticulum (ER) and induces ER stress. However, the link between the clinical severity of PMD and the cellular response induced by mutant PLP1 remains largely unknown. Accumulation of misfolded proteins in the ER generally leads to up-regulation of ER chaperones to alleviate ER stress. Here, we found that expression of PLP1A243V mutant, which causes severe disease, depletes some ER chaperones with a KDEL (Lys-Asp-Glu-Leu) motif, in HeLa cells, MO3.13 oligodendrocytic cells and primary oligodendrocytes. The same PLP1 mutant also induces fragmentation of the Golgi apparatus (GA). These organelle changes are less prominent in cells with milder disease-associated PLP1 mutants. Similar changes are also observed in cells expressing another disease-causing gene that triggers ER stress, as well as in cells treated with brefeldin A, which induces ER stress and GA fragmentation by inhibiting GA-to-ER trafficking. We also found that mutant PLP1 disturbs the localization of KDEL receptor, which transports the chaperones with KDEL motif from the GA to the ER. These data show that PLP1 mutants inhibit GA-to-ER trafficking, which reduces the supply of ER chaperones and induces GA fragmentation. We propose that depletion of ER chaperones and GA fragmentation induced by mutant misfolded proteins contribute to the pathogenesis of inherited ER stress-related diseases and affect the disease severity.
    Journal of Biological Chemistry 01/2013; · 4.65 Impact Factor
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    ABSTRACT: Tolosa-Hunt syndrome (THS) is a rare disorder, especially in the pediatric population, characterized by unilateral painful ophthalmoplegia with a relapsing-remitting course. Because the diagnosis of THS is based on the exclusion of other causes of painful ophthalmoplegia, attention should be paid to possible alternative diagnoses. Thallium-201 chloride ((201)Tl) scintigraphy has been used to evaluate tissue histology in clinical oncology with a marker, the retention index (RI). A higher value indicates histological malignancy. Although its utility in pediatric THS has not been discussed, we suggest that (201)Tl scintigraphy may be informative as a marker in the diagnosis. We present an 11-year-old boy with THS who was evaluated with (201)Tl scintigraphy before treatment with corticosteroids, when he had headache, photophobia, and diplopia. The RI of (201)Tl indicated that the lesion would be benign. Although his clinical symptoms did not fulfill the THS criteria completely, his eye symptoms disappeared 2 weeks after corticosteroid treatment, which was not within the 72h as in the diagnostic criteria of THS. He has been symptom-free for more than 2years with only an initial 4-week corticosteroid therapy. This report not only shows the potential of (201)Tl scintigraphy to contribute to the correct diagnosis of pediatric THS but also suggests the possibility that the diagnosis of THS could be supported uniquely even in a pediatric THS-suspicious patient who did not fulfill the current THS criteria completely. In conclusion, we suggest that (201)Tl scintigraphy may be useful for making the diagnosis of THS, especially in pediatric patients.
    The Tohoku Journal of Experimental Medicine 01/2013; 229(1):83-6. · 1.37 Impact Factor
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    ABSTRACT: Aim  To investigate the association between magnetic resonance imaging (MRI) patterns and motor function, epileptic episodes, and IQ or developmental quotient in patients born at term with spastic diplegia. Method  Eighty-six patients born at term with cerebral palsy (CP) and spastic diplegia (54 males, 32 females; median age 20y, range 7-42y) among 829 patients with CP underwent brain MRI between 1990 and 2008. The MRI and clinical findings were analysed retrospectively. Intellectual disability was classified according to the Enjoji developmental test or the Wechsler Intelligence Scale for Children (3rd edition). Results  The median ages at diagnosis of CP, assignment of Gross Motor Function Classification System (GMFCS) level, cognitive assessment, and MRI were 2 years (range 5mo-8y), 6 years (2y 8mo-19y), 6 years (1y 4mo-19y), and 7 years (10mo-30y) respectively. MRI included normal findings (41.9%), periventricular leukomalacia, hypomyelination, and porencephaly/periventricular venous infarction. The frequency of patients in GMFCS levels III to V and intellectual disability did not differ between those with normal and abnormal MRI findings. Patients with normal MRI findings had significantly fewer epileptic episodes than those with abnormal ones (p=0.001). Interpretation  Varied MRI findings, as well as the presence of severe motor dysfunction and intellectual disability (despite normal MRI), suggest that patients born at term with spastic diplegia had heterogeneous and unidentified pathophysiology.
    Developmental Medicine & Child Neurology 11/2012; · 2.68 Impact Factor
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    ABSTRACT: PLP1 amino acid substitutions cause accumulation of misfolded protein and induce endoplasmic reticulum (ER) stress, causing Pelizaeus-Merzbacher disease (PMD), a hypomyelinating disorder of the central nerve system. Currently no effective therapy is available for PMD. Promoted by its curative effects in other genetic disease models caused by similar molecular mechanisms, we tested if curcumin, a dietary compound, can rescue the lethal phenotype of a PMD mouse model (myelin synthesis deficient, msd). Curcumin was administered orally to myelin synthesis deficit (msd) mice at 180 mg·kg(-1)·day(-1) from the postnatal day 3. We evaluated general and motor status, changes in myelination and apoptosis of oligodendrocytes by neuropathological and biochemical examination, and transcription levels for ER-related molecules. We also examined the pharmacological effect of curcumin in cell culture system. Oral curcumin treatment resulted in 25% longer survival (p<0.01). In addition, oligodendrocytes undergoing apoptosis were reduced in number (p<0.05). However, no apparent improvement in motor function, neurological phenotype, and myelin formation was observed. Curcumin treatment did not change the expression of ER stress markers and subcellular localization of the mutant protein in vitro and/or in vivo. Curcumin partially mitigated the clinical and pathological phenotype of msd mice, although molecular mechanisms underlying this curative effect are yet undetermined. Nonetheless, curcumin may serve as a potential therapeutic compound for PMD caused by PLP1 point mutations.
    Molecular Genetics and Metabolism 03/2012; 106(1):108-14. · 2.83 Impact Factor
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    ABSTRACT: Mutations in NKX2-1 cause neurological, pulmonary, and thyroid hormone impairment. Recently, the disease was named brain-lung-thyroid syndrome. Here, we report three patients with brain-lung-thyroid syndrome. All patients were unable to walk until 24 months of age, and still have a staggering gait, without mental retardation. They have also had choreoathetosis since early infancy. Genetic analysis of NKX2-1 revealed a novel missense mutation (p.Val205Phe) in two patients who were cousins and their maternal families, and a novel 2.6-Mb deletion including NKX2-1 on chromosome 14 in the other patient. Congenital hypothyroidism was not detected on neonatal screening in the patient with the missense mutation, and frequent respiratory infections were observed in the patient with the deletion in NKX2-1. Oral levodopa did not improve the gait disturbance or involuntary movement. The results of (99m)Tc-ECD single-photon emission computed tomography (ECD-SPECT) analyzed using the easy Z-score imaging system showed decreased cerebral blood flow in the bilateral basal ganglia, especially in the caudate nuclei, in all three patients, but no brain magnetic resonance imaging (MRI) abnormalities. These brain nuclear image findings indicate that NKX2-1 haploinsufficiency causes dysfunction of the basal ganglia, especially the caudate nuclei, resulting in choreoathetosis and gait disturbance in this disease.
    Journal of the neurological sciences 12/2011; 315(1-2):77-81. · 2.32 Impact Factor
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    ABSTRACT: We report a case of a 3-year-old boy with acute muscle weakness that initially affected neck and all four limbs but later vanished from the lower limbs. Pharyngeal palsy was not observed during the course. All deep tendon reflexes were absent. Peripheral nerve conduction studies showed a demyelination pattern in each limb. The patient received intravenous high-dose corticosteroid hormone, followed by two immunoglobulin therapies. His muscle strength gradually improved after treatment and was almost completely restored four months later. We ultimately diagnosed the condition as the pharyngeal-cervical-brachial variant of Guillain-Barré syndrome, in consideration of the patient's muscle weakness of the neck and four limbs, the greater degree of weakness of the upper limbs versus the lower limbs. His clinical presentation was atypical for the pharyngeal-cervical-brachial variant of Guillain-Barré syndrome, as he presented no pharyngeal muscle weakness or anti GT1a antibodies, typical manifestations of the condition.
    No to hattatsu. Brain and development 11/2011; 43(6):482-5.
  • Neuroscience Research - NEUROSCI RES. 01/2011; 71.
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    ABSTRACT: A girl aged 1 year 9 months had recurrent episodes of febrile status epilepticus. She recovered completely after the first three episodes. However, at 9 months she developed acute encephalopathy resulting in severe neurologic sequelae. Diffusion-weighted magnetic resonance imaging revealed diffuse high-intensity signals over the cortex and subcortical white matter in the acute phase and severe diffuse cerebral atrophy in the chronic phase. Mutations were detected in the neuronal voltage-gated sodium channel alpha subunit type 1 (SCN1A) gene. SCN1A sequence analysis revealed a truncation mutation:e x1-c.126Adel (D43fs). Our patient was likely afflicted by severe myoclonic epilepsy in infancy, and the fourth episode of status epilepticus was similar to acute encephalopathy. This report provides further insight into the molecular pathophysiology underlying acute encephalopathy.
    Epilepsia 09/2010; 51(9):1886-8. · 3.96 Impact Factor

Publication Stats

19 Citations
27.53 Total Impact Points

Institutions

  • 2012–2014
    • National Center of Neurology and Psychiatry
      • Department of Mental Retardation and Birth Defect Research
      Кодаиры, Tōkyō, Japan
  • 2011–2013
    • Tohoku University
      • Department of Pediatrics
      Sendai, Kagoshima, Japan