Shoulder Pain - Don't Forget First Rib Fractures.

First rib fractures are uncommon, mainly in paediatric population, considering its anatomic features and their skeleton plasticity. Traditional teaching usually characterizes it as a hallmark of severe trauma. Herein, to unfold awareness to an unnoticed diagnosis, we describe two paediatric cases of isolated first rib fracture in adolescents without a clear identifiable cause nor an underlining trauma mechanism. Neurovascular injuries should always be investigated, as fracture of the first rib with ensuing callus formation is a rare but fearing cause of thoracic outlet syndrome. We highlight the scarcity of reports on isolated first rib fractures outside of sports medicine, as well as the importance of considering this otherwise easily missed diagnosis in a common complaint in children.

Increased extracellular matrix deposition during chondrogenic differentiation of dental pulp stem cells from individuals with neurofibromatosis type 1: an in vitro 2D and 3D study.

BACKGROUND: Neurofibromatosis 1 (NF1) presents a wide range of clinical manifestations, including bone alterations. Studies that seek to understand cellular and molecular mechanisms underlying NF1 orthopedic problems are of great importance to better understand the pathogenesis and the development of new therapies. Dental pulp stem cells (DPSCs) are being used as an in vitro model for several diseases and appear as a suitable model for NF1. The aim of this study was to evaluate in vitro chondrogenic differentiation of DPSCs from individuals with NF1 using two-dimensional (2D) and three-dimensional (3D) cultures. RESULTS: To fulfill the criteria of the International Society for Cellular Therapy, DPSCs were characterized by surface antigen expression and by their multipotentiality, being induced to differentiate towards adipogenic, osteogenic, and chondrogenic lineages in 2D cultures. Both DPSCs from individuals with NF1 (NF1 DPSCs) and control cultures were positive for CD90, CD105, CD146 and negative for CD13, CD14, CD45 and CD271, and successfully differentiated after the protocols. Chondrogenic differentiation was evaluated in 2D and in 3D (pellet) cultures, which were further evaluated by optical microscopy and transmission electron microscopy (TEM). 2D cultures showed greater extracellular matrix deposition in NF1 DPSCs comparing with controls during chondrogenic differentiation. In semithin sections, control pellets hadhomogenous-sized intra and extracelullar matrix vesicles, whereas NF1 cultures had matrix vesicles of different sizes. TEM analysis showed higher amount of collagen fibers in NF1 cultures compared with control cultures. CONCLUSION: NF1 DPSCs presented increased extracellular matrix deposition during chondrogenic differentiation, which could be related to skeletal changes in individuals with NF1.