Chemodynamic therapy (CDT), employing metal ions to transform endogenous H2O2 into lethal hydroxyl radicals (•OH), has emerged as an effective approach for tumor treatment. Yet, its efficacy is diminished by glutathione (GSH), commonly overexpressed in tumors. Herein, a breakthrough strategy involving extracellular vesicle (EV) mimetic nanovesicles (NVs) encapsulating iron oxide nanoparticles (IONPs) and β-Lapachone (Lapa) was developed to amplify intracellular oxidative stress. The combination, NV-IONP-Lapa, created through a serial extrusion from ovarian epithelial cells showed excellent biocompatibility and leveraged magnetic guidance to enhance endocytosis in ovarian cancer cells, resulting in selective H2O2 generation through Lapa catalysis by NADPH quinone oxidoreductase 1 (NQO1). Meanwhile, the iron released from IONPs ionization under acidic conditions triggered the conversion of H2O2 into •OH by the Fenton reaction. Additionally, the catalysis process of Lapa eliminated GSH in tumor, further amplifying oxidative stress. The designed NV-IONP-Lapa demonstrated exceptional tumor targeting, facilitating MR imaging, and enhanced tumor suppression without significant side effects. This study presents a promising NV-based drug delivery system for exploiting CDT against NQO1-overexpressing tumors by augmenting intratumoral oxidative stress.

文章主要介绍军队区域放射卫生监督机构组织实施放射诊疗许可管理的主要程序和方法,分析了医疗机构存在的放射诊疗建设项目卫生审查未开展、放射诊疗设备性能检测未全覆盖、放射防护与质量控制设备用品配备不全、放射工作人员职业健康体检未有效落实、个人剂量监测和放射防护培训不规范等影响许可审批的主要问题,提出了既符合法规标准要求、又切合军队当前放射诊疗工作实际的许可对策,总结了军队新的体制编制条件下做好医疗机构放射诊疗许可管理工作的体会和建议,对更好推动军队放射诊疗许可工作具有指导意义.

Tumor hypoxic environment is an inevitable obstacle for photodynamic therapy (PDT) of melanoma. Herein, a multifunctional oxygen-generating hydrogel loaded with hyaluronic acid-chlorin e6 modified nanoceria and calcium peroxide (Gel-HCeC-CaO2) was developed for the phototherapy of melanoma. The thermo-sensitive hydrogel could act as a sustained drug delivery system to accumulate photosensitizers (chlorin e6, Ce6) around the tumor, followed by cellular uptake mediated by nanocarrier and hyaluronic acid (HA) targeting. The moderate sustained oxygen generation in the hydrogel was produced by the reaction of calcium peroxide (CaO2) with infiltrated H2O in the presence of catalase mimetic nanoceria. The developed Gel-HCeC-CaO2 could efficiently alleviate the hypoxia microenvironment of tumors as indicated by the expression of hypoxia-inducible factor -1α (HIF-1α), meeting the "once injection, repeat irradiation" strategy and enhanced PDT efficacy. The prolonged oxygen-generating phototherapy hydrogel system provided a new strategy for tumor hypoxia alleviation and PDT.

目的 了解辖区医疗机构放射诊断场所辐射防护基本情况,为采取有效的放射防护监督管理措施提供依据.方法 2020年10-12月对辖区内38家医疗机构285台放射诊断设备进行辐射防护监督检测,并对结果进行分析.结果 285个放射诊断场所防护检测合格率为94.74％,其中口腔CT的合格率最低(80.00％),其次是CT(86.75％)和DR(97.87％).检测合格率低的位置主要是候诊区防护门(97.34％)、控制室防护门(97.72％)和观察窗(99.28％).防护设施检查合格率由高到低分别为通风系统(95.44％)、电离辐射警告标识(96.84％)、工作状态指示灯(80.70％)、防护用品(75.79％)、操作位可视机房防护门(49.12％)和候诊区注意事项告知栏(30.53％).结论 38家医疗机构放射诊断场所的整体防护水平比往年有所提高,但还存在不少安全隐患,特别是针对受检者的防护措施有待进一步加强.卫生部门需严格放射诊疗许可管理,对防护合格率较低的场所和部位重点监督和管理,确保放射防护各项措施落实到位.