ABSTRACT
Objective To improve the biological fidelity of the thorax flexible body in the original MADYMO child human model,so as to further study pediatric thorax injuries of child occupant.Methods The finite element model of six-year-old pediatric thorax was built by the method of reverse modeling based on CT images.By replacing the thorax model with flexible body in MADYMO six-year-old human model,an improved human model containing biomechanical thorax model was developed.The model was verified by joint validation of two tests,including Irwin and Mertz's method of scaling channel reported in Kroell's adult chest impact experiment and Ouyang's thoracic impact test on pediatric cadavers.Results The response of this established thorax model was in good agreement with scaling channel method and cadaver test data,and the thorax model was much more accurate than the original flexible body model.The resilience of simulation model was consistent with cadaver test.Conclusions The validity of the model is verified,and the results can be further used for occupant injury analysis in vehicle frontal crash.
ABSTRACT
Objective To investigate the correlation between immune inflammation and overactivity of T helper cells in childhood asthma by cell proliferation assay and activation induced cell death in vitro.Methods Th1/Th2/Th17 cytokines were determined by cytometric bead array.Cell proliferation and activation induced cell death were detected when CD4+ T cells were purified by magnetic beads and stimulated by PHA and antiCD3.At last,mRNA of Fas,FasL and Bcl-2 were mesured by real-time PCR.Results Cytokines of IL-4(2.451± 1.052ng/L vs 1.796 ±0.615 ng/L,P =0.018),IL-10( 1.920 ±0.813ng/L vs 1.390 ±0.162ng/L,P =0.006)and TNF(5.112 ±5.842 ng/L vs 1.506 ±0.551 ng/L,P =0.009) in sera of asthma group were higher than those in control group.Compared to control group,proliferation ability of CD4 + T cells in asthma group was greater ( OD450:0.498 ± 0.052 vs 0.274 ± 0.032,P ＜ 0.001 ) and apoptosis rate was lower( 35.62 ± 0.05 ％ vs 65.28±3.85％,P ＜0.001 ).mRNA expression of Fas in asthma group was lower but Bcl-2 was higher than those in control group.Conclusion It is implicated that defective expression of Fas and over expression of Bcl-2 in CD4+ T cells may contribute to apoptosis inhibition and cell proliferation,which could explain overeactivity of CD4 + T cells and lvmphocvte infiltration in childhood asthma.