Objective To explore the biomechanical characteristics of different types of lumbar disc herniation(LDH),and provide a theoretical basis for the clinical classification,diagnosis,and treatment of LDH.Methods A normal lumbar spine model with spinal nerves and four types of LDH models(central type,paracentral type/lateral recess type,intervertebral foramen type,extreme type)were constructed,and the biomechanical characteristics of the intervertebral discs and nerve roots in neutral posture and under six degrees of freedom conditions were analyzed.Results In neutral position,the stress of normal intervertebral disc was carger than that of the herniated intervertebral disc,and the stress ratio of annulus fibrosus and nucleus pulposus in normal model was greater than that of annulus fibrosus and nucleus pulposus in herniated models.In neutral position,the disc stress was mainly concentrated at the incisor between the protrusion and normal part,and recruitment occurred at outer edge of the disc.In flexion and extension position,the stress of the herniated intervertebral disc shifted to the right side.The maximum stress of herniated intervertebral disc appeared during right flexion,and the nerve root stress on the right side was carger than that on the left side.The stress of the herniated intervertebral disc during right rotation was slightly lower than that during right flexion,and the stress of nerve root on the right side was smaller than that on the left side.Conclusions The intervertebral disc is important in maintaining lumbar dynamic and static stability and flexibility.Different positions have an obvious effect the intervertebral disc stress.For patients with LDH,forward bending,flexion of the affected side and large extension should be avoided.Appropriate rotation of the affected side can help relieve the symptoms of nerve root compression.

Objective To explore the biomechanical safety of applying traditional Chinese orthopedic manipulation therapy after anterior cervical discectomy and fusion(ACDF)surgery,so as to provide a theoretical basis for clinical treatment in biomechanics.Methods Based on CT data,a three-dimensional finite element model of the normal C0-T1 cervical spine was established,and an ACDF postoperative finite element model of the C5-6 segment was constructed on this basis.Cervical spine rotation manipulation was simulated at the C4 and C7 segments of both models,and the von Mises stresses of the vertebral body,bilateral facet joints,intervertebral discs,and internal fixation system under manipulation loading of the C4 and C7 segments in both models were compared and analyzed.Results When the C4 segment was manipulated,the stress on the C5,C6,and C7 vertebral bodies in the ACDF postoperative model decreased by 12.3％,11.5％,and 26.4％,compared to the normal model.The stress on the left facet joints of the C4-5,C5-6,and C6-7 segments decreased by 12.3％,58.8％,and 15.4％,and the stress on the right facet joints decreased by 16.6％,92.1％,and 17.2％.The stress on the C4-5 and C6-7 segments decreased by 13.2％and 4.0％,while the maximum stress of the fusion cage,titanium plate,and screws in the C5-6 segment were 9.349,111.9,and 300.8 MPa.When the C7 segment was manipulated,the stress on the C4,C5,and C6 vertebral bodies in the ACDF postoperative model increased significantly compared to the normal model,especially the C5 vertebral body,with an increase of nearly 18 times.Except for the stress on the left facet joint of the C4-5 segment increased by 57.7％,the stress on the bilateral facet joints of other segments generally decreased,but the stress on the C4-5 and C6-7 segments increased by 43.2％and 21.7％and the stresses on the fusion cage,titanium plate,and screws in the C5-6 segment were 2.926,205.4,and 256.2 MPa.Conclusions The safety of performing manipulation on the upper vertebral body of the fusion segment after ACDF surgery is relatively high,but performing manipulation on the lower vertebral body of the fusion segment may lead to stress concentration and increase the risk of injury.When postoperative conservative treatment is implemented,the manipulation safety and indications should be considered to avoid operations in high-risk areas,and more precise and safe manipulation intervention treatment should be implemented based on the specific postoperative biomechanical state of the patient.

Objective To explore the biomechanical characteristics of different types of lumbar disc herniation(LDH),and provide a theoretical basis for the clinical classification,diagnosis,and treatment of LDH.Methods A normal lumbar spine model with spinal nerves and four types of LDH models(central type,paracentral type/lateral recess type,intervertebral foramen type,extreme type)were constructed,and the biomechanical characteristics of the intervertebral discs and nerve roots in neutral posture and under six degrees of freedom conditions were analyzed.Results In neutral position,the stress of normal intervertebral disc was carger than that of the herniated intervertebral disc,and the stress ratio of annulus fibrosus and nucleus pulposus in normal model was greater than that of annulus fibrosus and nucleus pulposus in herniated models.In neutral position,the disc stress was mainly concentrated at the incisor between the protrusion and normal part,and recruitment occurred at outer edge of the disc.In flexion and extension position,the stress of the herniated intervertebral disc shifted to the right side.The maximum stress of herniated intervertebral disc appeared during right flexion,and the nerve root stress on the right side was carger than that on the left side.The stress of the herniated intervertebral disc during right rotation was slightly lower than that during right flexion,and the stress of nerve root on the right side was smaller than that on the left side.Conclusions The intervertebral disc is important in maintaining lumbar dynamic and static stability and flexibility.Different positions have an obvious effect the intervertebral disc stress.For patients with LDH,forward bending,flexion of the affected side and large extension should be avoided.Appropriate rotation of the affected side can help relieve the symptoms of nerve root compression.

Objective To explore the biomechanical safety of applying traditional Chinese orthopedic manipulation therapy after anterior cervical discectomy and fusion(ACDF)surgery,so as to provide a theoretical basis for clinical treatment in biomechanics.Methods Based on CT data,a three-dimensional finite element model of the normal C0-T1 cervical spine was established,and an ACDF postoperative finite element model of the C5-6 segment was constructed on this basis.Cervical spine rotation manipulation was simulated at the C4 and C7 segments of both models,and the von Mises stresses of the vertebral body,bilateral facet joints,intervertebral discs,and internal fixation system under manipulation loading of the C4 and C7 segments in both models were compared and analyzed.Results When the C4 segment was manipulated,the stress on the C5,C6,and C7 vertebral bodies in the ACDF postoperative model decreased by 12.3％,11.5％,and 26.4％,compared to the normal model.The stress on the left facet joints of the C4-5,C5-6,and C6-7 segments decreased by 12.3％,58.8％,and 15.4％,and the stress on the right facet joints decreased by 16.6％,92.1％,and 17.2％.The stress on the C4-5 and C6-7 segments decreased by 13.2％and 4.0％,while the maximum stress of the fusion cage,titanium plate,and screws in the C5-6 segment were 9.349,111.9,and 300.8 MPa.When the C7 segment was manipulated,the stress on the C4,C5,and C6 vertebral bodies in the ACDF postoperative model increased significantly compared to the normal model,especially the C5 vertebral body,with an increase of nearly 18 times.Except for the stress on the left facet joint of the C4-5 segment increased by 57.7％,the stress on the bilateral facet joints of other segments generally decreased,but the stress on the C4-5 and C6-7 segments increased by 43.2％and 21.7％and the stresses on the fusion cage,titanium plate,and screws in the C5-6 segment were 2.926,205.4,and 256.2 MPa.Conclusions The safety of performing manipulation on the upper vertebral body of the fusion segment after ACDF surgery is relatively high,but performing manipulation on the lower vertebral body of the fusion segment may lead to stress concentration and increase the risk of injury.When postoperative conservative treatment is implemented,the manipulation safety and indications should be considered to avoid operations in high-risk areas,and more precise and safe manipulation intervention treatment should be implemented based on the specific postoperative biomechanical state of the patient.

Objective To investigate the co-transfection of p53 and angiostatin gene in the inhibition of SG7901. Methods Transfected the pVITRO2-hp53-hAS into SG7901 with lipofectamine.After transfection, RT-PCR were used to know whether the aimed gene had been transfected and expressed or not. Cell clones trial, MTT growth curve, cell cycle measuring were used to analyze the differences. Results The cells were suppressed by the two genes and inhibition of the combined genes is more powerful than single one. Conclusion The effection of combined genes pVITRO2-hp53-hAS on SG7901 is stronger than either single one. Combined-gene-therapy is a useful anti-carcinoma method.

Purpose:To investigate the status of p16 gene and its influence in p16 mRNA expression in primary hepatocellular carcinoma (HCC). Methods:The methylation status of p16 gene and expression of p16 mRNA were examined by methylation-specific PCR (MSP) and RT-PCR in twenty-five primary HCC and corresponding paracancerous tissue specimens.Results:Methylation was detected in 12 of 25 (52.0%) tumor tissue specinmens, while 6 of 25 (24.0%) in corresponding paracancerous tissue specimens. Loss of p16 mRNA expression was found in 19 specimens with methylated p16 gene,while expression of p16 mRNA was detected in 27 of 31 specimens with unmethylated p16 gene. There was significant difference in mRNA expression between specimens with methylated p16 and unmethylated p16.Conclusions:p16 gene methylation is a frequent event in HCC. The methylation of p16 gene might lead to loss of p16 mRNA expression. Detection of p16 gene methylation may be a useful marker in the molecular diagnosis of hepatocellular carcinomas.