Changes of cdk5, p35 and p53 gene expression levels in arsenic-induced neural cell apoptosis / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the expression levels of cdk5, p35 and p53 genes in arsenic trioxide (As2O3O)-induced neuron apoptosis and to explore the potential mechanism.</p><p><b>METHODS</b>The cultured primary rats' neurons were divided into 5 groups, which were exposed to 0, 1, 5, 10 micromol/L As2O3 and dimethyl sulfoxide (DMSO) for 8 h, respectively. The cell viability and cell apoptosis were detected by MTT colouration methods and flow cytometry, respectively. The real-time fluorescence quantitative PCR was used to measured the expression levels of cdk5, p35 and p53 genes.</p><p><b>RESULTS</b>The cell viability inhibition rates were 16.77%, 19.72% and 27.81% in 1, 5, 10 micromol/L As203 groups, respectively. Compared to the untreated group and DMSO group, the cell apoptosis rates were significantly increased in 5 and 10 micromol/L As2O3 groups (P < 0.05). The expression levels of cdk5, p35 and p53 genes increased with the exposure doses of AsO3. However, there were no significant differences in p35 gene expression between different dose subgroups (P > 0.05). There were significant differences in cdk5 and p53 gene expression between different dose subgroups (P < 0.05). The expression levels of cdk5 gene in 5 and 10 micromol/L As2O3 groups were significantly higher than those in untreated group and DMSO group (P < 0.05). The expression levels of p53 gene in 1, 5 and 10 micromol/L As2O3 groups were significantly higher than that in untreated group (P < 0.05). The expression level of p53 gene in 10 mciromol/L As2O3 group was significantly higher than that in DMSO group (P < 0.05).</p><p><b>CONCLUSION</b>Cdk5, p35 and p53 genes may involve in the process of As2O3-induced neural cell apoptosis.</p>

Experimental study on viscoelasticity of lumbar yellow ligament in young and old people / 医用生物力学

Objective To compare the stress relaxation and mechanical properties of creep viscoelasticity in the young and old’s spine and to provide the reference for the mechanical mechanism of viscoelasticity of yellow ligament degeneration. Method Twenty specimens of elderly patients with degenerative lumbar yellow ligament degeneration as the older group, and twenty specimens of young patients with lumbar yellow ligament injuries as the youth group were used respectively. All the yellow ligament specimens were from the yellow ligament between the fourth and fifth of lumbar vertebra (L4~L5). Stress relaxation experiment and creep experiment were conducted on the specimens by the strain increasing speed as 1%/s and the stress increasing speed as 0.5 MPa/s respectively. The experimental temperature was (36.5±0.5) ℃ and the experimental time was 7 200 s. Ninety stress relaxation and creep data were collected, and the data were dealt with the statistical analysis and normalization methods. Results The 7 200 s stress of yellow ligament in the youth group decreased by 1.42 MPa, while the 7 200 s stress of yellow ligament in the older group decreased by 1.91 MPa. The 7 200 s strain of yellow ligament in the youth group increased by 3.39%, while the 7 200 s strain of yellow ligament in the older group increased by 2.07%. The 7 200 s stress in two groups all increased and the increased strain data showed statistically significance (P<0.05). The stress relaxation curve changed in the form of logarithm and the creep curve changed in the form of index. Conclusions The 7 200 s stress relaxation and creep in the yellow ligament of the older group all decreased and the mechanical properties of viscoelasticity changed.

Effects of Airborne Particles on Micronuclear Frequency of Human Binucleate Lymphocytes / 环境与健康杂志

Objective To study the effects of airborne particles exposure on the micronucleus frequency of human binucleate lymphocytes. Methods Airborne particles were collected at a residential area of Taiyuan city with classification air samplers.The organic substance was extracted by dichloromethane acetone and methanol in a Soxhlet apparatus. Four metals,Ni Pb Cd and Cr in airborne particles were extracted by 1∶1 nitric acid and determined by atomic absorption spectrophotometry.The mutagenicity of the extracts of airborne particles was studied with cytokinesis-locking assay. Results The content of airborne particles in the area was 0.791 9 mg/m3exceeded the related standard by 4.28 times. The small particles contained more metals elements and organic substances than the big particles. The extracts of airborne particles induced a significant increase in micronucleus production P