Stromal cells of giant cell tumor of bone show primary cilia in giant cell tumor of bone.

Giant cell tumor of bone (GCTB) is a locally aggressive primary bone neoplasm composed by tumoral stromal cells (SCs) and a reactive component that consists of monocytic/histiocytic cells that give rise by fusion to osteoclast-like multinucleated cells. Recently, specific Histone 3.3 mutations have been demonstrated in SCs of GCTB. Many of the pathways related to bone proliferation and regulation depend on the primary cilium, a microtubule-based organelle that protrudes outside the cell and acts as a sensorial antenna. In the present work, we aimed to study the presence and role of primary cilia in GCTB. Ultrastructural, immunohistochemical, and immunofluorescence studies were performed in order to demonstrate, for the first time, that the primary cilium is located in spindle-shaped SCs of GCTB. Moreover, we showed Hedgehog (Hh) signaling pathway activation in these cells. Hence, primary cilia may play a relevant role in GCTB tumorogenesis through Hh signaling activation in SCs. RESEARCH HIGHLIGHTS: Transmission electron microscopy allows describing and differentiating cellular subpopulations in giant cell tumor of bone (GCTB). The primary cilium is present in some tumoral stromal cells of GCTB. Hedgehog signalling is activated in these cells.

International trauma care: initial European approaches during the COVID 19 pandemic.

The world was not prepared for the global of pandemic in early 2020 with the arrival of COVID 19. Europe has some of the most developed health care systems in the world and this article explains the initial response to the pandemic from an orthopaedic and trauma viewpoint from 8 nations. Italy reported the first cluster in February, which then rapidly spread around the continent, requiring a rapid reorganization of services. The reports highlight how elective surgery was universally stopped, surgical services were reconfigured, and new practices, such as the widespread use of telemedicine, may well become permanent. It also emphasizes how the pandemic has re-educated us on the importance of a consistent and central approach to deal with a global health crisis, and how medical services need to remain flexible and responsive to new ways of working.