ABSTRACT
Objective To explore dynamic characteristics of the gait for the elderly with different fall risks before and after obstacle crossing. Methods Twenty-seven elderly people in community were graded as fall risk by using the time up and go test and five-time sit to stand test. The plantar pressure parameters of the elderly before and after obstacle crossing were measured and analyzed by foot pressure measurement system. Results There was no significant difference in the characteristic value of bimodal curve of overall plantar pressure between the high and low fall risk groups before and after obstacle crossing(P>0.05). The center of pressure (COP) trajectory in X direction of high fall risk group after obstacle crossing was significantly greater than that of low fall risk group (P0.05). Conclusions The support time of the elderly with high fall risk is longer than that of the elderly with low fall risk during obstacle crossing, the peak pressure of plantar metatarsal region of the crossing leg increases, and the plantar COP curve shows asymmetry, with an increase in transverse range of the coronal plane. In clinical evaluation, plantar pressure characteristics of people with fall risks during obstacle crossing should be focused on.
ABSTRACT
Objective To study the preparation method of compound tissue-engineering scaffolds of the PLA/silk fibroin and evaluate its biological features.Methods The PLA scaffolds matrix were dipped into the silk fibroin solution,then dried,and PLA/silk fibroin scaffolds were prepared.There were two groups in the experiment,one group was PLA group,and the other one was compound scaffolds group.According to ISO-10993 standard,hematolysis test,dynamic coagulation time test,cell toxicity test,stimulation test and pyrogen test were performed in two groups,and the results were compared betwen two groups.Results In the stimulation test,the two kinds of materials had equally not aroused the obvious animal skin stimulation,it showed that the experiment was in accordance with the standard.In the pyrogen test,the two scaffolds material aroused the animal temperature rising without exception under 0.2℃ and the total number of degree was under 1.0℃,therefore there was no obvious difference between two groups.In the hematolysis test,the hemolysis rates of the two scaffolds samples were smaller than 5% equally(P=0.000),which indicated that the hemolysis of the compound scaffolds was better than that of the PLA scaffolds.In the dynamic coagulation time test,the coagulation time of the compound scaffolds(37 min) was longer than that of the PLA scaffolds(26 min).The anti-coagulation ability of the compound scaffolds was better than that of the PLA scaffdds.In the cell toxicity test,the cell growth situation of the compound scaffolds group was obviously better than that of the PLA group,and at the meantime the cell toxicity of the compound scaffolds was obviously smaller than that of the PLA scaffolds.Conclusion The material of PLA/silk fibroin compound scaffolds has the advanced biological consistent compared with the simplex scaffolds.Accordingly,the PLA/silk fibroin can be used as a scaffolds matrix to be transplanted into the body.
ABSTRACT
[Objective]To investigate the feasibility of the dermal pluripotent stem cells in the repairing of cartilage defects.It was aimed to provide experimental basis in view of cartilage defects of expanding the repair of cartilage defects seed cells selection. [Method]Neonatal cyanotic blue rabbits were used.Dermal tissue directly isolated through mechanical method and cells through enzymatic digestion were obtained.The growth characteristics of adherent adhesion of stem cells were used to obtain high cloned cells,which were subcultured.The cell concentration of 1?106/ml was cultured with polylactic acid scaffold for one weeks,and the obtained result was implanted into full-thickness articular cartilage defects of rabbits.Thirty cyanotic blue rabbit(60 joints)for about 3~5 months were randomly divided into three groups:dermal pluripotent stem cell / scaffold polylactic acid in group A,polylactic acid scaffold in group B,controls in group C.Twenty joints for each group.The rabbits were killed by air embolization at 12 weeks,restoration organization was extracted and stained by HE and toluidine blue.According to the repairing result of cartilage defect,gross and histologic scoring was made,and analyzed by statistics.The comparison of score difference between each groups was performed statistically.[Result]Gross and histological observation demonstrated that in group A organizations had smooth surface,appeared transparent,good integration with surrounding cartilage and subchondral bone.In group B there was a tiny transparent cartilage,and the fiber cartilage repair accounted for much proportion.The surface of group C showed some defects,mainly characterized by fibrous cartilage repair.After gross and histological observations statistics score analysis was performed.Results showed that group A is the most optimal(P