著者

幸原 伸夫 川本 未知 石井 淳子 村瀬 翔

出版者

一般社団法人 日本臨床神経生理学会

雑誌

臨床神経生理学 (ISSN:13457101)

巻号頁・発行日

vol.44, no.1, pp.28-35, 2016-02-01 (Released:2017-03-01)

参考文献数

17

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LEMSは非特異的な疲労感が主訴となることが多いが, 近位筋の筋力低下と腱反射の低下, 口渇を認める患者をみたときにはLEMSを疑う必要がある。診断は手筋のCMAP振幅低下を確認し, 筋収縮後のCMAP振幅の増大をみることで容易に行える。10秒間の筋収縮終了直後に電気刺激を加え, 60%以上の振幅増大を認めたときにはLEMSの可能性がきわめて高い。神経末端のP/Q型電位依存性Caイオンチャンネルに対する抗体の存在が本症候群の原因であり, 陽性率は約90%である。対症療法として抗コリンエステラーゼ剤のほか3,4ジアミノピリジン (3,4 DAP) が有用である。悪性腫瘍を伴う場合は原因治療および免疫治療が, 伴わない場合は対症療法を中心として長期のフォローアップが重要である。

著者

石井 淳子 山本 司郎 吉村 元 藤堂 謙一 川本 未知 幸原 伸夫

出版者

日本神経学会

雑誌

臨床神経学 (ISSN:0009918X)

巻号頁・発行日

vol.55, no.3, pp.165-170, 2015 (Released:2015-03-17)

参考文献数

26

被引用文献数

2 5

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症例は82歳女性.呼吸困難で入院し,白血球17,700/μl,好酸球52%(9,204/μl),好酸球増多をおこす基礎疾患をみとめず,特発性好酸球増加症候群(hypereosinophilic syndrome; HES)と診断した.第6病日に左上下肢麻痺が出現し,頭部MRIで両側大脳半球分水嶺領域・小脳に散在性多発微小脳梗塞をみとめた.心エコーで左室壁全周性に血栓をみとめ,Löffler心内膜心筋炎合併による左室内血栓からの多発脳塞栓症であると考えた.抗凝固およびプレドニゾロン内服開始後,脳梗塞の再発はなかった.HESの合併症として脳梗塞を呈した際は,心内膜心筋障害を評価し早期治療介入が必要である.

著者

最上 善広 石井 淳子 馬場 昭次

出版者

日本宇宙生物科学会

雑誌

Biological Sciences in Space (ISSN:09149201)

巻号頁・発行日

vol.9, no.1, pp.17-35, 1995 (Released:2006-02-01)

参考文献数

28

被引用文献数

4 3

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In order to get an insight into the cellular mechanisms for the integration of the effects of gravity,we investigated the gravitactic behaviour in Paramecium. There are two main categories for the model of the mechanism of gravitaxis; one is derived on the basis of the mechanistic properties of the cell (physical model) and the other of the physiological properties including cellular gravireception (physiological model). In this review article, we criticized the physical models and introduced a new physiological model. Physical models postulated so far can be divided into two; one explaining the negative gravitactic orientation of the cell in terms of the static torque generated by the structural properties of the cell (gravity-buoyancy model by Verworn, 1889 and drag-gravity model by Roberts, 1970), and the other explaining it in terms of the dynamic torque generated by the helical swimming of the cell (propulsion-gravity model by Winet and Jahn, 1974 and lifting-force model by Nowakowska and Grebecki, 1977). Among those we excluded the possibility of dynamic-torque models because of their incorrect the oretical assumptions. According to the passive orientation of Ni2+-immobilized cells, the physical effect of the static torque should be inevitable for the gravitactic orientation. Downward orientation of the immobilized cells in the course of floating up in the hyper-density medium demonstrated the gravitactic orientation is not resulted by the nonuniform distribution of cellular mass (gravity-buoyancy model) but by the for-aft asymmetry of the cell (drag-gravity model). A new model explaining the gravitactic behaviour is derived on the basis of the cellular gravity sensation through mechanoreceptor channels of the cell membrane. Paramecium is known to have depolarizing receptor channels in the anterior and hyperpolarizing receptors in the posterior of the cell. The uneven distribution of the receptor may lead to the bidirectional changes of the membrane potential by the selective deformation of the anterior and posterior cell membrane responding to the orientation of the cell in the gravity field; i.e. negative- and positive-going shift of the potential due to the upward and downward orientation, respectively. The orientation dependent changes in membrane potential with respect to gravity, in combination with the close coupling of the membrane potential and the ciliary locomotor activity, may allow the changes in swimming direction along with those in the helical nature of the swimming path; upward shift of axis of helix by decreasing the pitch angle due to hyperpolarization in the upward-orienting cell, and also the upward shift by increasing the pitch angle due to depolarization in the downward-orienting cell. Computer simulation of the model demonstrated that the cell can swim upward along the “super-helical” trajectory consisting of a small helix winding helically an axis parallel to the gravity vector, after which the model was named as “super-helix model”. Three-dimensional recording of the trajectories of the swimming cells demonstrated that about a quarter of the cell population drew super-helical trajectory under the unbounded, thermal convection-free conditions. In addition, quantitative analysis of the orientation rate of the swimming cell indicated that gravity-dependent orientation of the swimming trajectory could not be explained solely by the physical static torque but complementarily by the physiological mechanism as proposed in the super-helix model.