Riichiro Kishimoto

Hokkaido University, Sapporo-shi, Hokkaido, Japan

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Publications (4)7.25 Total impact

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    ABSTRACT: To confirm the reported findings and clarify unknown clinical features of Churg-Strauss syndrome (CSS)-associated neuropathy and design appropriate treatment. We assessed the clinical features of 6 patients with CSS-associated neuropathy. Mononeuritis multiplex was present in 4 cases and polyneuropathy in the remaining cases. Both groups progressed to sensori-motor polyneuropathy in an acute or subacute course. All cases showed bronchial asthma and eosinophilia. Two cases with serum antineutrophil cytoplasmic antibodies to myeloperoxidase (MPO-ANCA) had an acute clinical course and severe symptoms. Nerve conduction studies (NCS) of these 2 cases revealed conduction blocks at the initial stage, although NCS finally indicated sensori-motor axonopathy at the involved extremities. For treatment, high-dose corticosteroid therapy for 4 cases, and cyclophosphamide combined with corticosteroids for 1 case, were effective. For the remaining case, intravenous immunoglobulin (IVIg) at the chronic phase resulted in a slow improvement of neuropathy in the symptomatic aspect. There was no relapse of neuropathy with low-dose corticosteroid treatment for 14-24 months after the initial treatment, except 1 case. There was also no relapse in the other case that was treated with moderate-dose steroids. Our study showed that CSS-associated neuropathy is a treatable disorder and that the first choice therapy is high-dose corticosteroid. In cases where corticosteroids are ineffective or for severe cases, immunosuppressive therapy (cyclophosphamide) with steroids should be considered, and IVIg might be a treatment option.
    Clinical neurology and neurosurgery 08/2009; 111(8):683-7. · 1.30 Impact Factor
  • Nihon Naika Gakkai Zasshi 09/2007; 96(8):1709-11.
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    ABSTRACT: The endoplasmic reticulum (ER) is important for maintaining the quality of cellular proteins. Various stimuli can disrupt ER homeostasis and cause the accumulation of unfolded or misfolded proteins, i.e., a state of ER stress. Recently, ER stress has been reported to play an important role in the pathogenesis of neurological disorders such as cerebral ischemia and neurodegenerative diseases, but its involvement in the spinal cord diseases has not been fully discussed. We conducted this study using tunicamycin (Tm) as an ER stress inducer for rat spinal cord in organotypic slice culture, a system that we have recently established. Tm was shown to induce ER stress by increased expression of GRP78. The viability rate of spinal cord neurons decreased in a dose-dependent manner with Tm treatment, and dorsal horn interneurons were more vulnerable to Tm-induced neurotoxicity. A p53 inhibitor significantly increased the viability of dorsal horn interneurons, and immunofluorescence studies showed nuclear accumulation of p53 in the dorsal horns of Tm-treated spinal cord slices. These findings suggest that p53 plays an important role in the killing of dorsal horn interneurons by Tm. In contrast, motor neurons were not protected by the p53 inhibitor, suggesting that the role of p53 may vary between different cell types. This difference might be a clue to the mechanism of the stress-response pathway and might also contribute to the potential application of p53 inhibitors for the treatment of spinal cord diseases, including amyotrophic lateral sclerosis.
    Journal of Neuroscience Research 03/2007; 85(2):395-401. · 2.97 Impact Factor
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    ABSTRACT: A dysfunctional ubiquitin-proteasome system recently has been proposed to play a role in the pathogenesis of neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). We have shown previously that spinal motor neurons are more vulnerable to proteasome inhibition-induced neurotoxicity, using a dissociated culture system. To confirm this toxicity, we used organotypic slice cultures from rat neonatal spinal cords, which conserve the structure of the spinal cord in a horizontal plane, enabling us to identify motor neurons more accurately than in dissociated cultures. Furthermore, such easy identifications make it possible to follow up the course of the degeneration of motor neurons. When a specific proteasome inhibitor, lactacystin (5 microM), was applied to slice cultures, proteasome activity of a whole slice was suppressed below 30% of control. Motor neurons were selectively damaged, especially in neurites, with the increase of phosphorylated neurofilaments. They were eventually lost in a dose-dependent manner (1 microM, P < 0.05; 5 microM, P < 0.01). The low capacity of Ca(2+) buffering is believed to be one of the factors of selectivity for damaged motor neurons in ALS. In our system, negative staining of Ca(2+)-binding proteins supported this notion. An intracellular Ca(2+) chelator, BAPTA-AM (10 microM), exerted a significant protective effect when it was applied with lactacystin simultaneously (P < 0.01). We postulate that proteasome inhibition is an excellent model for studying the mechanisms underlying selective motor neuron death and searching for new therapeutic strategies in the treatment of ALS.
    Journal of Neuroscience Research 11/2005; 82(4):443-51. · 2.97 Impact Factor