稲垣 健志

中枢神経系に作用する一般用医薬品の濫用により突然死に至った若年者の２剖検例を経験したので報告する。 事例１は20歳代の女性。自宅のトイレ内で淡褐色調の吐瀉物にまみれて死亡していた。死者の居室には市販のカフェイン製剤20錠分が空になったPTP包装シートが遺留されていた。剖検で心臓血中に致死濃度のカフェインが検出された。事例２は10歳代の女性。自室内で死亡していた。周囲には市販の鎮咳薬デキストロメトルファンの空になったPTP包装シートが大量に遺留されていた。剖検で心臓血中に致死濃度のデキストロメトルファンが検出された。 一般用医薬品の多くは，未成年者であっても比較的容易に入手できる。その手軽さの一方で濫用による死亡事例は後を絶たない。市販薬の説明文書には過剰摂取による毒性や薬物代謝の個人差，薬物相互作用に関する記載はなく，濫用や依存に対する注意喚起と適正使用の啓発の必要が強く示唆された。 キーワード： Dextromethorphan (デキストロメトルファン)，Caffeine (カフェイン)，一般用医薬品，薬物過剰摂取，突然死

Objective: To report on a volunteer-led program supporting local healthcare providers (L-HCPs) and disaster responders after the 2024 Noto Peninsula Earthquake, focusing on its implementation and immediate outcomes. Methods: A volunteer-led initiative established by university alumni deployed medical teams to a local hospital on weekends following the earthquake, providing onsite support to relieve L-HCPs from prolonged strain. The program integrated information and communication technology (ICT) platforms to enable remote support, communication, and structured debriefing sessions for volunteers, facilitating assistance from a wider network. Results: The project effectively sustained the local health care institution's capacity by managing diverse patient needs, including a surge in internal medical conditions. It provided essential respite, allowing local physicians crucial personal time, for which they expressed profound gratitude. Volunteer doctors reported effective stress management through the onsite and ICT-based support structure, and the initiative concluded safely without injury. Conclusions: The project demonstrated that combining onsite medical assistance with strategically implemented ICT effectively mitigates burnout among L-HCPs, providing essential psychological support for deployed volunteers. The findings highlight the significance of sustained recovery-phase support, professional networks, and ICT in disaster response. These experiences highlight the need for comprehensive, system-wide support strategies for all frontline personnel in future disasters. Keywords: Disaster medicine; burnout; health personnel; information technology; mental health; professional

White matter injury is caused by cerebral blood flow disturbances associated with stroke and demyelinating diseases such as multiple sclerosis. Remyelination is induced spontaneously after white matter injury, but progressive multiple sclerosis and white matter stroke are usually characterised by remyelination failure. However, the mechanisms underlying impaired remyelination in lesions caused by demyelination and stroke remain unclear. In the current study, we demonstrated that collagen fibres accumulated in the demyelinated lesions of multiple sclerosis patients (age range 23-80 years) and white matter lesions of stroke patients (age range 80-87 years), suggesting that the accumulation of collagen fibres correlates with remyelination failure in these lesions. To investigate the function of collagen fibres in the white matter lesions, we generated two types of white matter injury in mice. We induced focal demyelination by lysolecithin (LPC) injection and ischemic stroke by endothelin 1 (ET1) injection into the internal capsule. We found that type I collagen fibres were secreted in ET1-induced lesions with impaired white matter regeneration in the chronic phase of disease. We also showed that monocyte-derived macrophages that infiltrated into lesions from the peripheral blood produced type I collagen after white matter injury, and that type I collagen also exacerbated microglial activation, astrogliosis, and axonal injury. Finally, we demonstrated that oligodendrocyte differentiation and remyelination were inhibited in the presence of type I collagen after LPC-induced demyelination. These results suggest that type I collagen secreted by monocyte-derived macrophages inhibited white matter regeneration, and therefore, the modulation of type I collagen metabolism might be a novel therapeutic target for white matter injury.