Effects of bioactive modification of poly-D,L-lactide acid scaffolds on the biological behaviors of the seed cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the changes in the biological behavior of bone marrow mesenchymal stem cells (BMSCs) transfected with red fluorescent protein by lentivirus (RFP-BMSCs) seeded on in poly-D, L-lactide acid (PDLLA) scaffolds with bioactive modification by ammonia plasma and Gly-Arg-Gly-Asp-Ser (GRGDS) in vitro.</p><p><b>METHODS</b>Circular sheets of PDLLA scaffolds (8 mm in diameter and 1 mm in thickness) were prepared and aminated with PDLLA (group A) or modified with the peptide conjugate A/PDLLA (group PA), with untreated PDLLA as the control (group P). The RFP-BMSCs were seeded on the scaffold materials and their proliferation and metabolic activity were detected using CyQuant NF and Alamar blue staining. The mineralization on the scaffolds was observed using calcein fluorescent dye under a fluorescent microscope. The adhesion and proliferation of RFP-BMSCs were observed by fluorescent microscope, and scanning electron microscope (SEM) was used to confirm the observed adhesion of the seed cells.</p><p><b>RESULTS</b>The RFP-BMSCs seeded on the 3 scaffolds all showed proliferative activity at different time points after cell seeding, and the cell numbers decreased significantly in the order of PA>A>P (P<0.001). The cell number was significantly greater in group PA than in group A at all the time points except for days 10 (P=0.077) and 12 (P=0.491), and gradually became similar with the passage of time. The metabolic changes of the cells follow a similar pattern of cell proliferation. RFP-BMSCs showed more active proliferation in group A and group PA than in group P. On days 14 and 21, the intensity of green fluorescence decreased in the order of group PA, A and P. The RFP-BMSCs showed better adhesion in group PA than in group A, and the cells in group P appeared more scattered under scanning electron microscope.</p><p><b>CONCLUSION</b>Bioactive modification of PDLLA by ammonia treatment and conjugation with GRGDS peptides may promotes the adhesion, proliferation, metabolism and mineralization of RFP-BMSCs seeded on PDLLA scaffolds.</p>

Three-dimensional visualization of virtual surgery for intertrochanteric fractures / 南方医科大学学报

<p><b>OBJECTIVE</b>To establish a computer-aided three-dimensional visualization operation simulation system based on Mimics and Unigraphics NX software to provide reliable evidence for accurate preoperative surgical planning.</p><p><b>METHODS</b>The preoperative CT scans of 5 patients with intertrochanteric fractures were used for three-dimensional reconstruction of intertrochanteric fractures using Mimics software. Three-dimensional reconstruction of the surgical instruments was carried out using the modeling function of Unigraphics NX software, whose assembly function was used to visualize the simulates internal fixations of intertrochanteric fractures with dynamic hip screw (DHS) system. The operative procedures simulated by Unigraphics NX were analyzed preoperatively.</p><p><b>RESULTS</b>The virtual surgery procedures were clearly and vividly visualized in three dimensions. The fracture reduction and surgical effects could be predicted using this system.</p><p><b>CONCLUSIONS</b>This system of three-dimensional visualization of virtual surgery for intertrochanteric fractures has important values in surgical planning, risk assessment and clinical training, and can help improve the reliability and outcome of orthopedic surgery.</p>

Establishment of a digital Evans-Jensen classification model of femoral intertrochanteric fracture / 南方医科大学学报

<p><b>OBJECTIVE</b>To establish a digitized Evans-Jensen classification model of femoral intertrochanteric fracture.</p><p><b>METHODS</b>The hip of a healthy male volunteer was examined with 64-slice spiral CT, and the data were processed using Mimics 10.01 software to reconstruct the proximal femur model. According to Evans-Jensen classification criteria of femoral intertrochanteric fracture, each type of fracture model was simulated. Five orthopedic surgeons and 10 medical students undertook the preliminary evaluation of the digital fracture model.</p><p><b>RESULTS</b>The digital fracture model is intuitive, three-dimensional, and realistic with good visual effect. The fracture could be observed and charted from optional direction and angle. The corresponding animation allowed 360 degrees rotation. Evaluation by the 4 orthopedic surgeons and 10 medical students confirmed that the digital fracture model was intuitive and easy to understand.</p><p><b>CONCLUSION</b>The digital model of femoral intertrochanteric fracture is intuitive, three-dimensional, realistic and dynamic, and may help in clinical practice and medical teaching.</p>