Proliferation and differentiation of endogenous neural stem cells in subventricular zone in rats after traumatic craniocerebral injury / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the time course of proliferation and differentiation of neural stem cells (NSCs) in the subventricular zone (SVZ) of rats following traumatic craniocerebral injury (TBI).</p><p><b>METHODS</b>Forty-eight SD rats were randomized into 3 groups, namely the control group without any treatment, the sham-operated group with scalp incision and preparation of a cranial window, and TBI group with craniocerebral injury induced by Feeney's method. With nestin and BrdU as two cell markers, NSE as the neuron-specific marker and GFAP as the glial cell marker, immunofluorescence assay with double labeled antibodies was performed to examine the proliferation and differentiation of endogenous NSCs in the SVZ at different time points after TBI.</p><p><b>RESULTS</b>s The numbers of cells positive for nestin/NSE, nestin/GFAP, BrdU/NSE, and BrdU/GFAP in the SVZ of the rats increased significantly after TBI. The positive cells began to increase at 1 day after TBI, reached the peak level at day 3 and became normal at day 14, showing significant differences between the time points of measurement following TBI and from the cell numbers in the control group measured at the same time points. The cells positive for nestin/ GFAP showed the most distinct increase in the SVZ of the rats with TBI.</p><p><b>CONCLUSION</b>TBI results in mobilization of the NSCs in the SVZ on the injured side to cause the proliferation and differentiation of the endogenous NSCs. The SVZ is one of the most important germinal centers of NSC proliferation and differentiation.</p>

Kinetic characteristics of gymnastic vault springboard / 医用生物力学

Objective To analyze the dynamics of vault springboard designated to using in formal competitions by the Federation International de Gymnastique (FIG), and find a new method measuring the reaction force of the springboard, so as to provide scientific supports for diagnosis of its take-off technique. Methods The stiffness values of GYMNOVA soft and hard springboards were derived by method of material mechanics, then the springboards were then tested with static, dynamic experiments and computer simulations. In the static experiment, two video cameras with the sample frequency of 600 Hz were placed at a 90° angle to capture the deformation of the springboards under the loads of 160, 180, 210 and 230 kg, respectively. In the dynamic experiment, a volunteer performed drop jump (DJ) from a 1.25 m high platform onto the hard and soft springboards, respectively, while a camera was employed to capture the deformation at the sample frequency of 300 Hz. All the three cameras were calibrated using a 2-dimensional framework, and the changes of the board height, velocity under different loads and acceleration of center of mass (COM) of the human body in DJ experiment were all obtained by digitizing the videos using SIMI MOTION software. Finally, modeling and computer simulation were performed to simulate the DJ in the dynamic experiment. Results The equation F=kx+c describing force-displacement of both the springboard was obtained. The depressing displacements of the board under different loads in the static experiment were close to those calculated by the equation. The vertical reaction force curve in DJ calculated by the equation was highly correlated to that obtained by acceleration of COM. The coefficient of multiple correlation was all greater than 0.86. Conclusions The study developed a new method for measuring the vertical reaction force of the springboard based on board depressing displacement and velocity with the help of high-speed camera. This method, which can be employed with convenience to rapidly monitor the board reaction force during take-off, provides scientific supports for enhancement of vaulting techniques and plays an active role in prevention of vaulting injuries.