BACKGROUND:Mesenchymal stem cells from human skeletal muscle exhibit multi-directional differentiation potential under the influence of osteogenic proteins such as bone morphogenetic protein 4 (BMP4). But the differentiation of a specific cell subpopulation is not yet clear.OBJECTIVE:To characterize the multi-directional differentiation potential of mesenchymal stem cells from human skeletal muscle based on the expression of different surface markers.METHODS:Four different subpopulations were isolated from the human skeletal muscle by fluorescence-activated cell sorting based on their expression of the myogenic-specific marker CD56 and the endothelial-specific markers CD34 and CD144, including CD56+, CD56+CD34+CD144+, CD34+CD144+, and unsorted groups. Osteogenic differentiation of the four groups of the cells was displayed by Von Kossa staining after the treatment with BMP4 alone or BMP4 plus transforming growth factor β3. Chondrogenic differentiation of these cells was displayed by Alcian blue staining. Bone metabolism was assessed by alkaline phosphatase staining.RESULTS AND CONCLUSION:No significant difference in the bone metabolism was found among four groups after the treatment with BMP4 (P > 0.05). Osteogenic and chondrogenic potentials of the four cell subpopulations were significantly different. Under the same osteogenic induction, the CD56+ cells exhibited strongest potential for osteogenic differentiation; and under the same chondrogenic induction, the CD56+CD34+CD144+ cells exhibited better potential for chondrogenic differentiation than the CD56+ cells. These findings indicate that the osteogenic and chondrogenic potentials are intimately associated with the type of mesenchymal stem cells from human skeletal muscle:the CD56+ cells are closely related to the osteogenic potential, while the CD56+CD34+CD144+ cells have stronger chondrogenic potential.

BACKGROUND:Early postural adjustments serve as preparatory measures for forthcoming actions or potential disruptions in posture,thereby facilitating improved movement execution and mitigating destabilizing effects caused by posture interference. OBJECTIVE:To investigate the characteristics of temporal and intensity parameters of key lower limb muscles during early postural adjustment phase when stroke patients with varying levels of balance initiate walking at a self-selected comfortable pace. METHODS:The characteristics of early postural adjustments in 16 stroke patients were observed.Sixteen patients were divided into a non-fall group(n=8)and a fall group(n=8)based on the history of falls and Berg Balance Scale scores.Noraxon inertial sensors and Noraxon Ultium EMG wireless surface electromyography were utilized to collect body kinematic data and surface electromyography data during gait initiation.Muscle activation time and activation sequence of six key muscles in the lower limbs(tibialis anterior,medial and lateral gastrocnemius,rectus femoris,lateral femoris and biceps femoris muscles)during the early postural adjustment phase,as well as normalized electromyography integral values for the four time windows(each 150 ms)before gait initiation,were analyzed. RESULTS AND CONCLUSION:Stroke patients with a history of falls exhibited earlier activation times for the six key muscles in the lower limbs during gait initiation compared with those in the non-fall group.The fall group demonstrated significantly earlier activation times for tibialis anterior,lateral head of gastrocnemius,and vastus lateralis(P<0.01,P<0.05).In contrast,the non-fall group displayed a consistent pattern of activating extensor muscles before flexor muscles,with thigh muscle activation preceding calf muscle activation.However,in the fall group,calf extensor muscle activation occurred prior to thigh extensor muscle activation,and the vastus lateralis was activated even earlier.The tibialis anterior was the last activated muscle in both groups.Specifically during T3(>-300 to-150 ms),the tibialis anterior exhibited significantly higher activity in the fall group compared with the non-fall group(P<0.05),while the lateral head of gastrocnemius demonstrated significant inhibition during T3(P<0.05)and the medial head of gastrocnemius showed significant inhibition during both T3 and T4(>-150 to 0 ms)stages compared with the non-fall group(P<0.01,P<0.05).To conclude,stroke patients with varying balance abilities employ distinct early postural adjustment strategies prior to stepping,as evidenced by differences in muscle activation timing,recruitment order,and muscle activity amplitude.Patients at a high risk of falling exhibit prolonged duration of early postural adjustment and delayed initiation of gait,indicating earlier activation of the tibialis anterior muscle and inhibition of gastrocnemius muscle activity.These delays in gait initiation and variations in muscle recruitment strategies may contribute to unstable posture and an increased susceptibility to falls.

Objective:To investigate the effect of transcranial direct current stimulation (tDCS) on the behavior and the mismatch negativity (MMN) component of the auditory evoked potential of autistic children.Methods:Thirty-four autistic children were randomly divided into an anode stimulation group ( n=19) and a pseudo-stimulation group ( n=16). Both groups were given one hour of routine rehabilitation five times a week for 4 weeks, while the anode stimulation group was additionally provided with 20 minutes of tDCS 3 times a week. Before and after the treatment, both groups′ behavior was evaluated by using autism behavior checklist (ABC) as well as any changes in MMN of the auditory evoked EEG signals. Results:There were no significant differences between the two groups in any of the measurements before the treatment. Afterwards behavior had improved significantly in both groups, with significantly greater improvement in the stimulated group. In the stimulated group the average MMN amplitude had increased significantly and the average latency had decreased significantly. However, no such significant changes were observed in the pseudo-stimulation group. There was a significant linear correlation between the changes in the incubation period of MMN components and the improvements in ABC, vestibular functioning, tactile defense and proprioception.Conclusion:Anodal tDCS combined with conventional rehabilitation therapy can effectively increase the MMN amplitude and shorten the latency in autistic children, improving their brain function.