BACKGROUND: Implantation of bone marrow mesenchymal stem cells (BMSCs) is a potential alternative for promoting bone defects healing or osseointegration in osteoporosis. However, the reactive oxygen species (ROS) accumulated and excessive inflammation in the osteoporotic microenvironment could weaken the self-replication and multi-directional differentiation of transplanted BMSCs. METHODS: In this study, to improve the hostile microenvironment in osteoporosis, Poloxamer 407 and hyaluronic acid (HA) was crosslinked to synthetize a thermos-responsive and injectable hydrogel to load MnO2 nanoparticles as a protective carrier (MnO2 @Pol/HA hydrogel) for delivering BMSCs. RESULTS: The resulting MnO2 @Pol/HA hydrogel processed excellent biocompatibility and durable retention time, and can eliminate accumulated ROS effectively, thereby protecting BMSCs from ROS-mediated inhibition of cell viability, including survival, proliferation, and osteogenic differentiation. In osteoporotic bone defects, implanting of this BMSCs incorporated MnO2 @Pol/HA hydrogel significantly eliminated ROS level in bone marrow and bone tissue, induced macrophages polarization from M1 to M2 phenotype, decreased the expression of pro-inflammatory cytokines (e.g., TNFa, IL-1b, and IL-6) and osteogenic related factors (e.g., TGF-b and PDGF). CONCLUSION This hydrogel-based BMSCs protected delivery strategy indicated better bone repair effect than BMSCs delivering or MnO2 @Pol/HA hydrogel implantation singly, which providing a potential alternative strategy for enhancing osteoporotic bone defects healing.

Objective To analyze the effect of limited internal fixation contrasting micro -external fixator in the treatment of fractures around the hand.Methods Sixty patients with fractures around the hand treated in the First People′s Hospital of Huizhou from May 2015 to May 2017 were selected and randomly divided into the internal fixation group and the external fixation group,and then were treated with effective internal fixation and mini external fixator respectively.The curative effect,operation condition,postoperative recovery and complications of the two groups were compared.Results The treatment effect(excellent and good rate was 96.67%(29/30)),fracture recovery time((6.37 ± 1.25)weeks),hospitalization time((4.32 ±1.23)d)and postoperative complication rate(10.0%(3/30))in the external fixation group were superior to those in the internal fixation group(76.67%(23/30),(8.87 ± 2.12)weeks,(7.29 ± 2.15)d,33.3%(10/30)),the differences were statistically significant(P=0.032;t=15.459,P=0.005;t=17.788,P =0.001;P=0.012).However,there were no significant differences between the external fixation group and internal fixation group in the operation time and the blood loss during operation((28.41±2.87)min vs.(27.67±1.42)min;(16.87 ± 3.71)ml vs.(16.43 ± 2.89)ml)(t=2.459,P=0.423;t=1.788,P =0.619). Conclusion Compared with limited internal fixation,the mini external fixator is reliable and effective,with less complications,and is more conducive to the early activity and functional recovery of the patients with hand fractures.

Male primary adenocarcinoma of urethra is rare clinically. A patient with primary adenocarcinoma of posterior urethra complicated with intestinal metaplasia was admitted and underwent urethral mass resection. The tumor recurred 3 months after surgery and no further treatment was given for personal reasons. The purpose of this report is to improve clinicians' understanding of urethral cancer, so that patients can undergo more accurate diagnosis and treatment.