Publications by authors named "Daiji Obara"

Performing a cohort-based SARS-CoV-2 antibody assay is crucial for understanding infection status and future decision-making. The objective of this study was to examine consecutive antibody seroprevalence changes among hospital staff, a high-risk population. A two-time survey was performed in May and October 2020 for 545 hospital staff to investigate the changes in the results of the rapid kit test and chemiluminescence immunoassay (CLIA).

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This study suggests the importance of instituting accompanying measures to prevent potential negative mental and social impacts on people receiving false-positive results.

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Objectives: The objective of this study was to investigate the differences between the results of two serology assays for detection of COVID-19 among medical staff, who are at higher risks of infection.

Methods: The immunochromatography (ICG) rapid test kit and the chemiluminescence immunoassay (CLIA) quantitative antibody test were performed. The differences in IgM and IgG antibody prevalence in different serological assays were descriptively analyzed.

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A 77-year-old woman developed progressive dysesthesia, hypesthesia and weakness in four extremities immediately after improvement of herpes zoster in the left Th10 dermatome area. Examination of the cerebrospinal fluid (CSF) showed an increase in protein concentrations. Evidence of demyelinating polyneuropathy was demonstrated by nerve conduction studies.

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To determine the efficacy of low-dose FK506 in the treatment of myasthenia gravis (MG), untreated de novo patients were randomly selected to receive treatment with (n = 18) or without (n = 16) FK506, and were evaluated for 1 year after treatment with limitation of daily dose of prednisolone. Low-dose FK506 reduced the duration of early-phase therapy in hospital (p < 0.05) and the need for combined therapy with plasmapheresis and high-dose intravenous methylprednisolone or high-dose intravenous methylprednisolone alone (p < 0.

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To investigate the role of protein kinase Cdelta (PKCdelta) in angiotensin II-induced facilitation mechanisms of hypoxic neuronal damage and whether candesartan, an AT1 receptor antagonist, can suppress these mechanisms, we performed in vitro experiments which were free from vascular components using PC12 cells under hypoxic (12 h)/reoxygenation (0-48 h) conditions. Angiotensin II apparently increased the basal expression level of PKCdelta phosphorylated at Ser(643) before hypoxia, promoted the cleavage of PKCdelta to its catalytic fragment, and fostered the progression of DNA fragmentation after hypoxia. Candesartan inhibited both phosphorylation and cleavage of PKCdelta and suppressed the angiotensin II-induced facilitation of DNA fragmentation under hypoxic/reoxygenation conditions.

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A 59-year-old man developed progressive sensory dullness and muscle weakness in the extremities, facial palsy on the left side, and hoarseness 4 days after the onset of acute hepatitis A. Vibration and joint sensation in the extremities were severely affected. Anti-sulfatide IgM antibody level was initially elevated in serum, but diminished along with amelioration of the symptoms following intravenous immunoglobulin therapy.

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To investigate the role of dendritic cells (DCs) in the hyperplastic myasthenia gravis (MG) thymus, we studied the frequency and distribution of three mature DC phenotypes (CD83(+)CD11c(+), CD86(+)CD11c(+), and HLA-DR(+)CD11c(+)) in samples from patients with MG whose symptoms dramatically improved following thymectomy and in non-MG control thymuses. In hyperplastic MG thymuses, mature DCs were much more numerous in nonmedullary areas, such as the subcapsular/outer cortex; around the germinal centers; and in extralobular connective tissue, particularly around blood vessels. Mature DCs strongly coexpressed CD44 and appeared to be components of a CD44-highly positive (CD44(high)) cell population migrating from the vascular system.

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We examined interleukin-2 (IL-2) production by phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMs) from 75 untreated myasthenia gravis (MG) patients and 48 control patients. Patients with MG consisted of those with elevated PBM IL-2 production (>1,250 pg/ml; mean + 2SD of the controls) (n = 29, 39%) and those with normal PBM IL-2 production (<1,250 pg/ml) (n = 46, 61%). Significant characteristics of patients with elevated PBM IL-2 production included elevated serum levels of anti-acetylcholine receptor antibodies, severe generalized symptoms, thymic hyperplasia, and marked effects of thymectomy (p < 0.

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We compared the early effects of FK506 on clinical severity, interleukin-2 (IL-2) production by phytohemagglutinin-stimulated peripheral blood mononuclear cells (PBMs), and serum levels of acetylcholine receptor antibodies between myasthenia gravis (MG) patients with elevated (>1250 pg/ml, n = 9) or normal (<1250 pg/mL, n = 10) levels of PBM IL-2 production. Reduction in clinical severity and PBM IL-2 production were significantly greater in the patients with elevated IL-2 production than those with normal PBM IL-2 production in the first month of treatment.

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Phosphorylation of Akt induced under hypoxic or ischemic conditions has been reported only for residue Ser(473). We examined whether Akt can be phosphorylated at Thr(308), another phosphorylation site on Akt, and can exhibit neuroprotective effects under conditions of hypoxia/reoxygenation, comparing pheochromocytoma-12 (PC12) cells transfected with constitutively active Akt (Myr-pCMV cells) and those transfected with pCMV vector only (pCMV cells). Expression levels of Akt phosphorylated at Ser(473) were 2.

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Over-expression of alpha7 nicotinic acetylcholine receptor (alpha7nAChR) in PC12 cells, independent of agonistic stimulation, induces marked neurite outgrowth and high capacity for migration and adherence (differentiation-like transformation), and increases tolerance against cell damage. In the present study, we investigated the effects of alpha7nAChR over-expression and nicotine on ERK phosphorylation and N-cadherin expression by comparing 3 groups of cells: PC12 cells transfected with alpha7 subunit cDNA (alpha7pCMV cells); untransfected PC12 cells exposed to 50 microM nicotine (PC12 cells+nicotine); and PC12 cells transfected with vector only (pCMV cells). alpha7 subunit protein was detected in alpha7pCMV cells at 24 to 72 h after transfection.

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We investigated the neuroprotective function of alpha7 nicotinic acetylcholine receptor (alpha7nAChR) after transient hypoxia (12 h) and reoxygenation (0-72 h), comparing rat pheochromocytoma (PC12) cells overexpressing FLAG-tagged alpha7nAChR (alpha7pCMV cells) and control PC12 cells (non-transfected or transfected with vector only) in medium with and without nicotine. Plasma membrane degradation in the early phase after hypoxia was inhibited in PC12 cells with nicotine, and more profoundly in alpha7pCMV cells with nicotine. Inhibition of DNA fragmentation in the late phase after hypoxia was most remarkable in alpha7pCMV cells with nicotine, but, surprisingly, it was more remarkable in alpha7pCMV cells without nicotine than in PC12 cells with nicotine.

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