[Research Progress in Promotion of Tissue Regeneration and Reconstruction with Exosomes Derived from Mesenchymal Stem Cells].

In regenerative medicine, stem cell therapy is an effective strategy for tissue regeneration and has a positive therapeutic effect on the regeneration and repair of defective tissues. In recent years, a series of studies have shown that the positive effects of stem cell therapy are mediated by exosomes released by the paracrine action of mesenchymal stem cells. Researchers have thus proposed a novel treatment strategy to use stem-cell-derived exosomes alone for tissue regeneration and repair, and affirmed through studies that the effects achieved were comparable to those of stem-cell-based therapies. Therefore, as a promising treatment strategy, exosome-based tissue regeneration treatment measures have been extensively studied. In this review, we discussed the latest knowledge of exosomes and the research progress in the regeneration and repair of related connective tissues, including the regeneration of bones, cartilage, skin, spinal cord and tendons, and briefly discussed the corresponding mechanisms. In addition, the challenges and prospects of tissue regeneration and repair based on mesenchymal stem cell exosomes were discussed.

Radiation protection and regulations for the nuclear medicine physician.

As authorized users of radioactive material, nuclear medicine (NM) physicians play a leading role in the use and management of these agents. Regarding patient management, NM physicians are responsible for ensuring both the appropriateness of exams and the associated patient doses. Along with radiologists, NM physicians are the ones developing and implementing processes that provide guidance to and dialog with referring physicians to ensure that patients receive the most appropriate type of imaging exams. Regarding regulatory compliance, in collaboration with radiation safety officers, NM physicians are the ones educating their staff about principles of radiation protection and radiation safety with adherence to regulations from agencies such as the Nuclear Regulatory Commission, the Department of Transportation, the Environmental Protection Agency, and the Food and Drug Administration. On occasion, these regulations and standards can be difficult to comprehend. This article is intended to serve as a condensed guide for NM physicians who are in the process of applying for a radioactive materials license, establishing a new radiation protection program, or want to ensure continued compliance and maintenance of safety and security of licensed materials in the clinical or research settings.