Risk factors related to coronary artery occlusion in female patients with ischemic angina pectoris / 中华心血管病杂志

Objective: To analyze the risk factors of coronary artery occlusion in female patients with ischemic angina pectoris. Methods: Clinical data of 1 600 patients (666 females and 934 males) who underwent coronary angiography from January 2013 to December 2015 due to angina pectoris in 6 major coronary intervention centers in China were retrospectively analyzed. The clinical characteristics were compared between the female and male groups, and between the non-obstructive coronary artery disease (INOCA) and ischemic obstructive coronary artery disease (IOCA) subgroups of female subjects with angina pectoris. The risk factors related to the degree of coronary artery occlusion in female patients were analyzed. Results: In the enrolled patients who underwent coronary angiography for angina pectoris, female group was older than the male group, and the proportion of patients with hypertension, diabetes and ischemia accompanied by IOCA was significantly higher than that of the male group (P<0.05). Univariate analysis showed that age≥65 years, hypertension, diabetes, and typical angina symptoms were associated with an increased risk of IOCA in female patients with angina pectoris. Multivariate regression analysis showed that age≥65 years old (OR=1.784, 95%CI: 1.146-2.776, P=0.010), hypertension (OR=1.782, 95%CI: 1.201-2.644, P=0.004) and typical angina symptoms (OR=1.642, 95%CI: 1.127-2.393, P=0.010) were independent risk factors for female patients with angina pectoris diagnosed as IOCA. The correlation analysis between the number of risk factors and the type of coronary artery disease obstruction showed that the incidence of INOCA decreased significantly with the increase of the number of risk factors, from 45.5% to 14.2%. The incidence of IOCA increased significantly with the number of risk factors, from 54.5% to 85.8% (P for trend<0.001). Conclusion: The incidence of INOCA in female patients with angina pectoris suspected of coronary heart disease is higher than that of male. The incidence of IOCA increased significantly, and the incidence of INOCA decreased significantly in proportion to the increase of the number of combined risk factors.

Safety evaluation of Tibetan medicine Qishiwei Zhenzhu Pills based on serum pharmacochemistry and network pharmacology / 中国中药杂志

To explore the mechanism of the active ingredients of Qishiwei Zhenzhu Pills in inhibiting the hepatorenal toxicity of the zogta component based on serum pharmacochemistry and network pharmacology, thereby providing references for the clinical safety application of Qishiwei Zhenzhu Pills. The small molecular compounds in the serum containing Qishiwei Zhenzhu Pills of mice were identified by high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS). Then, by comprehensively using Traditional Chinese Medicines Systems Pharmacology(TCMSP), High-throughput Experiment-and Reference-guided Database(HERB), PubChem, GeneCards, SuperPred, and other databases, the active compounds in the serum containing Qishiwei Zhenzhu Pills were retrieved and their action targets were predicted. The predicted targets were compared with the targets of liver and kidney injury related to mercury toxicity retrieved from the database, and the action targets of Qishiwei Zhenzhu Pills to inhibit the potential mercury toxicity of zogta were screened out. Cytoscape was used to construct the active ingredient in Qishiwei Zhenzhu Pills-containing serum-action target network, and STRING database was used to construct the protein-protein interaction(PPI) network of intersection targets. The Gene Ontology(GO) and Kyoto Encyclopedia of Genes and Genomes(KEGG) enrichment analyses were carried out on the target genes by the DAVID database. The active ingredient-target-pathway network was constructed, and the key ingredients and targets were screened out for molecular docking verification. The results showed that 44 active compounds were identified from the serum containing Qishiwei Zhenzhu Pills, including 13 possible prototype drug ingredients, and 70 potential targets for mercury toxicity in liver and kidney were identified. Through PPI network topology analysis, 12 key target genes(HSP90AA1, MAPK3, STAT3, EGFR, MAPK1, APP, MMP9, NOS3, PRKCA, TLR4, PTGS2, and PARP1) and 6 subnetworks were obtained. Through GO and KEGG analysis of 4 subnetworks containing key target genes, the interaction network diagram of active ingredient-action target-key pathway was constructed and verified by molecular docking. It was found that taurodeoxycholic acid, N-acetyl-L-leucine, D-pantothenic acid hemicalcium, and other active ingredients may regulate biological functions and pathways related to metabolism, immunity, inflammation, and oxidative stress by acting on major targets such as MAPK1, STAT3, and TLR4, so as to inhibit the potential mercury toxicity of zogta in Qishiwei Zhenzhu Pills. In conclusion, the active ingredients of Qishiwei Zhenzhu Pills may have a certain detoxification effect, thus inhibiting the potential mercury toxicity of zogta and playing a role of reducing toxicity and enhancing effect.

Clinical Observation on Orthopedics No.1 Prescription Combined with Celecoxib in Treating Knee Osteoarthritis with Middle Stage of Cold-dampness Syndrome / 中国实验方剂学杂志

Objective:To study the clinical efficacy of orthopedics No.1 prescription combined with celecoxib in the treatment of knee osteoarthritis （KOA） with middle stage of cold-dampness syndrome and investigate its effect on serum cytokines levels. Method:The 72 patients were randomly divided into control group and observation group， with 36 cases each. Patients in both groups were given basic treatment with oral celecoxib capsules （0.2 g/ time， 1 time/day）. On the basis of western medicine treatment， patients in observation group were treated with orthopedics No.1 prescription decoction-free granules by fumigation， 1 bag/time， 1 time/day， 5 times/week. Both groups received treatment for 4 weeks. The visual analog pain score （VAS）， American knee society knee score （KSS）， serum interleukin-1<italic>β </italic>（IL-1<italic>β</italic>）， tumor necrosis factor-<italic>α </italic>（TNF-<italic>α</italic>）， and transforming growth factor-<italic>β</italic>₁（TGF-<italic>β</italic>₁） levels were observed before and after treatment， and their clinical efficacy was evaluated. Result:After treatment， VAS score significantly decreased in both groups （<italic>P</italic><0.01）， and KSS score significantly increased （<italic>P</italic><0.01）， with better clinical effect in observation group. After treatment， serum IL-1<italic>β</italic> and TNF-<italic>α</italic> levels decreased significantly in both groups （<italic>P</italic><0.01）， and the levels in observation group were lower than those in control group after treatment （<italic>P</italic><0.05）. TGF<italic>-β</italic>₁content was significantly higher than that before treatment in two groups （<italic>P</italic><0.01）. Conclusion:Orthopedics No.1 prescription combined with celecoxib for the treatment of KOA with middle stage of cold-dampness syndrome can effectively relieve the clinical symptoms of patients with KOA， improve joint function， improve quality of life， reduce the contents of inflammatory factors IL-1<italic>β</italic> and TNF-<italic>α</italic> in serum， and increase the expression of TGF-<italic>β</italic>₁ level.

Effect of Zishenwan on Pyroptosis and Epithelial-Mesenchymal Transition of Renal Tubular Epithelial Cells in Diabetic Nephropathy Mice / 中国实验方剂学杂志

Objective:To study the efficacy and mechanism of Zishenwan （ZSW） against pyroptosis and epithelial-mesenchymal transition （EMT） of renal tubular epithelial cells in diabetic nephropathy （DN） mice， so as to provide evidence for the treatment of DN with ZSW. Method:The <italic>db/db</italic> mice with spontaneous diabetes were randomly divided into the model group， dapagliflozin （1.0 mg·kg^-1） group， and high-， medium-， and low-dose （6.0， 3.0， 1.5 g·kg^-1） ZSW groups. The non-diabetic <italic>db/m</italic> mice were classified into the normal group. The ones in the model and normal groups were given an equal volume of deionized water by gavage， while those in the other groups were intervened with the corresponding drugs for 12 weeks. The fasting blood glucose （FBG） level was tested at tail vein once every two weeks. The levels of urine albumin-creatinine ratio （ACR）， <italic>β</italic>-N-acetyl-D-glucosaminidase （NAG）， and cystatin C （CysC） were detected once every four weeks. After 12 weeks of administration， the blood sampled from eyeballs was used for measuring the blood urea nitrogen （BUN） and serum creatinine （SCr）. The pathological changes in renal tissues were observed by light microscopy and transmission electron microscopy. The expression of EMT markers in the renal tubular epithelium was analyzed by immunohistochemistry （IHC）. The in situ terminal end-labeling （TUNEL） staining was conducted to analyze the nuclear damage of renal tubular epithelial cells. The protein and mRNA expression levels of EMT markers， nucleotide-binding oligomerization domain-like receptor protein 3 （NLRP3） inflammasome and pyroptosis-related inflammatory cytokines in renal tissues were separately assayed by Western blot and Real-time fluorescence quantitative polymerase chain reaction（Real-time PCR）. Result:Compared with the normal group， the model group displayed significantly increased FBG， BUN， serum SCr， ACR， NAG， and CysC （<italic>P</italic><0.01）， impaired renal tissues， altered EMT marker expression intensities and levels （<italic>P</italic><0.01）， and elevated TUNEL-positive rate and protein and mRNA expression levels of pyroptosis-related inflammatory cytokines and NLRP3 inflammasome （<italic>P</italic><0.01）. Compared with the model group， ZSW and dapagliflozin significantly decreased the levels of FBG， BUN， serum SCr， ACR， NAG， and CysC （<italic>P</italic><0.01）， relieved the pathological injuries in renal tissues， changed the EMT marker expression intensities （<italic>P</italic><0.01） and protein and mRNA expression levels （<italic>P</italic><0.05， <italic>P</italic><0.01）， and down-regulated the TUNEL-positive rate （<italic>P</italic><0.01） of renal tubular epithelial cells as well as the protein and mRNA expression levels of pyroptosis-related inflammatory cytokines （<italic>P</italic><0.01） and NLRP3 inflammasome （<italic>P</italic><0.05， <italic>P</italic><0.01）. Conclusion:ZSW alleviates DN possibly by inhibiting pyroptosis and EMT in renal tubular epithelial cells.

Age-Related Changes of Material Mechanics and Bone Material Parameters of Rat Skulls / 法医学杂志

Objective To study the relationship between material mechanics and bone material parameters of rat skulls and their correlation with age by examination of the parameters. Methods Forty-eight healthy male SD rats were divided into 2, 4, 6, 8, 17, 26, 52 and 104 week groups according to their age. Each group had six rats. The right cranium was compressed by KD Ⅱ-0.2 microcomputer controlled electronic universal testing machine, and material mechanics parameters （ultimate load, compression strength and compression modulus） were measured, then the skull slices were cut off and scanned by Micro-CT system to detect bone material parameters （skull thickness, bone mineral density, bone volume, and trabecular thickness）. Results The differences in ultimate load, compression strength and compression modulus among all groups had statistical significance （P<0.05）, and were positively correlated with age within 26 weeks （P<0.05）. The differences in skull thickness, bone mineral density, bone volume and trabecular thickness among all groups had statistical significance （P<0.05）, and were positively correlated with age within 52 weeks （P<0.05）. All material mechanics parameters were positively correlated with bone material parameters （P<0.05）. Conclusion There is a positive correlation between bone material parameters （skull thickness, bone mineral density, bone volume, trabecular thickness）, material mechanics parameter （skull ultimate load, compression strength, compression modulus） and age in a certain range, which can be used to infer age.

Correlation analysis of mandarin fish (Siniperca chuatsi) growth hormone gene polymorphisms and growth traits

Screening of trait-associated molecular markers can be used to enhance the efficiency of selective breeding. Previously, we produced the first high-density genetic linkage map for the mandarin fish (Siniperca chuatsi) and identified 11 quantitative-trait loci significantly associated with growth, of which one is located within the growth hormone (GH) gene. To investigate the GH gene polymorphisms and their correlation with growth, the complete sequence was cloned and 32 single-nucleotide polymorphisms (SNPs) and one simple-sequence repeat (SSR)were identified. Of which, eight SNPs (G1–G8) and the SSR (GH-AG)were selected for genotyping and correlation analysis with growth traits in a random population. The results showed that the four novel polymorphicloci (G1, G2, G3 and GH-AG) were significantly correlated with growth traits of mandarin fish (P < 0.05). Of these, G1, G3 and GH-AG showed highly significant correlations with multiple growth traits (P < 0.01) and the combined SNP analysis showed that G1–G3 formed four effective diplotypes (D1–D4), among which D1 was highly significantly greater than D4 (P < 0.01) for some important growth traits. In conclusion, our results show that the four polymorphic loci G1–G3 and GH-AG within the mandarin fish GH gene are significantly correlated with growth traits and could be used as candidate molecular markers for selective breedingof superior varieties of mandarin fish.

Observations on the Efficacy of Scalp Acupuncture with Strong Stimulation in Treating Intractable Hiccup / 上海针灸杂志

Objective To investigate the efficacy of scalp acupuncture with strong stimulation plus oral hiccup decoction in treating intractable hiccup. Method One hundred patients with intractable hiccup were allocated, using a random number table, to treatment and control groups, 50 cases each. In addition to oral hiccup decoction in the two groups, the treatment group received scalp acupuncture with strong stimulation at the stomach and chest areas and the control group, electroacupuncture, for two courses of treatment. The times to produce the effect and the symptom frequency scores were compared between the two groups. Result After one course of treatment, the cure rate, the cure and marked efficacy rate and the total efficacy rate were 42％, 66％ and 78％, respectively, in the treatment group and 24％, 40％ and 68％, respectively, in the control group. There were statistically significant difference in the cure rate and the cure and marked efficacy rate (P<0.05) but no in the total efficacy rate (P>0.05) between the two groups. After two courses of treatment, the cure rate, the cure and marked efficacy rate and the total efficacy rate were 68％, 78％ and 88％, respectively, in the treatment group and 40％, 60％ and 74％, respectively, in the control group. There were statistically significant difference in the cure rate (P<0.05) but no in the cure and marked efficacy rate and the total efficacy rate (P>0.05) between the two groups. After one and two courses of treatment, there was a statistically significant difference in the hiccup frequency score between the treatment and control groups (P<0.05). The time to produce the effect was 2-5 hrs in the treatment group and 5-8 hrs in the control group. Conclusion The total efficacy rate of scalp acupuncture with strong stimulation for intractable hiccup is not significantly different from that of electroacupuncture, but the cure rate of the former was significantly higher than that of the latter. Scalp acupuncture with strong stimulation can produce a quick effect, reduce the frequency of hiccups and relieve symptoms accompanying hiccup.

In vitro study of genistein inducing apoptosis in MDA-MB-231 breast cancer cells via NF-κB and MAPK signaling pathways / 中国药理学通报

Aim To study the effect of genistein on apoptosis in human breast cancer MDA-MB-231 cells and the underlying mechanisms. Methods MTT as-say was used to observe the inhibitory rate on human breast cancer MDA-MB-231 cells treated with genistein. Colony assay was used to determine the cell colony formation rate on human breast cancer MDA-MB-231 cells treated with genistein. Western blot was used to detect the expression of Bcl-2, Bax, caspase-3,NF-κB, ERK, p-ERK, JNK and p-JNK in human breast cancer MDA-MB-231 cells treated with genistein. Results The results of MTT assay showed that genistein inhibited the viability of breast cancer MDA-MB-231 cells in a time- and concentration-de-pendent manner. Colony assay suggested that genistein had an antiproliferative effect on MDA-MB-231 cells. The expression levels of Bcl-2, NF-κB and p-ERK were significantly down-regulated compared with con-trol(P < 0.01). However, the expression of Bax, caspase-3 and p-JNK was significantly up-regulated(P<0.01). Conclusions Genistein could inhibit the growth of human breast cancer MDA-MB-231 cells and induce apoptosis,and the mechanism may be related to the inhibition of NF-κB, ERK/MAPK signaling path-ways and the activation of JNK/MAPK signaling path-way.

Effect of follower load on facet joint contact force of lumbar spine / 医用生物力学

Objective To study the influence of follower load on contact force of facet joints under various postures of lumbar spine. Methods A 3D nonlinear finite element model of lumbar spine (L1-S1) was developed, with consideration of the non-uniform thickness and nonlinear material properties of the cartilage layer in facet joints. The model was then applied with different follower preload (0, 0.5, 0.8, 1.2 kN), under pure moment of 7.5 N•m in different directions (flexion, extension, lateral bending, extension and torsion). The contact forces of facet joints on the two sides of each segment under different loading conditions were compared. The asymmetry influence of follower load on contact force of facet joints was also quantitatively studied. Results The follower preload increased the facet force under flexion-extension and bending (ipsilateral), while decreased the force on the contralateral facet under lateral bending. All the effects of follower load on facet force became weaker with the increase of preload. For torsion loading, the preload had almost no effect on facet force. The greatest asymmetry influence of follower load on facet force was under bending (the ipsilateral side), followed by flexion, bending (contralateral side), extension and torsion. Conclusions The follower load shows obviously different effects on contact force of facet joints with different postures. The asymmetry of facet joints should be fully considered in biomechanical studies of lumbar spine, especially in studies on post-structures of lumbar spine under physiological loads.

Biomechanical effects of interbody cage height on cervical spine / 医用生物力学

Objective To investigate the biomechanical effects of interbody cage height on cervical spine during anterior cervical discectomy and fusion (ACDF) surgery,so as to provide references for selection of interbody cage.Metheds The finite element model of normal cervical spine (C2-7) was built and validated,and the cages with different height (5,6,7,8 mm) were implanted into C5-6 disc (cage 5,6,7,8 model).All the models were loaded with pure moment of 1.5 N · m to produce flexion,extension,lateral bending and axial rotation motions on cervical spine,and the effects of cage height on range of motion (ROM),facet joint stress,intervertebral pressure in cervical spine were investigated.Results The intervertebral angle at the fusion segment increased by 0.68° with per 1 mm-increase in height.The ROM in C5-6 after cage implantation was smaller than 0.44°.The influence of cage height on ROM in C4-5 was greater than that in C6-7,and the changes of ROM in non-fusion segments were smaller than 7.3％.The cage height variation had a smaller impact on the facet joint stress and intervertebral pressure.The stresses in the capsular ligament,cage and screw-plate system increased gradually with the increase of cage height,and the stresses in cage 6,7,8 models were much higher than those in cage 5 model.Conclusions For patients who need implanting fusion cage,the cage height should be 0-1 mm greater than the original intervertebral space height.

Biomechanical effects of interbody cage height on cervical spine / 医用生物力学

Objective To investigate the biomechanical effects of interbody cage height on cervical spine during anterior cervical discectomy and fusion (ACDF) surgery,so as to provide references for selection of interbody cage.Metheds The finite element model of normal cervical spine (C2-7) was built and validated,and the cages with different height (5,6,7,8 mm) were implanted into C5-6 disc (cage 5,6,7,8 model).All the models were loaded with pure moment of 1.5 N · m to produce flexion,extension,lateral bending and axial rotation motions on cervical spine,and the effects of cage height on range of motion (ROM),facet joint stress,intervertebral pressure in cervical spine were investigated.Results The intervertebral angle at the fusion segment increased by 0.68° with per 1 mm-increase in height.The ROM in C5-6 after cage implantation was smaller than 0.44°.The influence of cage height on ROM in C4-5 was greater than that in C6-7,and the changes of ROM in non-fusion segments were smaller than 7.3％.The cage height variation had a smaller impact on the facet joint stress and intervertebral pressure.The stresses in the capsular ligament,cage and screw-plate system increased gradually with the increase of cage height,and the stresses in cage 6,7,8 models were much higher than those in cage 5 model.Conclusions For patients who need implanting fusion cage,the cage height should be 0-1 mm greater than the original intervertebral space height.

Soil pretreatment and fast cell lysis for direct polymerase chain reaction from forest soils for terminal restriction fragment length polymorphism analysis of fungal communities

Abstract Humic substances in soil DNA samples can influence the assessment of microbial diversity and community composition. Using multiple steps during or after cell lysis adds expenses, is time-consuming, and causes DNA loss. A pretreatment of soil samples and a single step DNA extraction may improve experimental results. In order to optimize a protocol for obtaining high purity DNA from soil microbiota, five prewashing agents were compared in terms of their efficiency and effectiveness in removing soil contaminants. Residual contaminants were precipitated by adding 0.6 mL of 0.5 M CaCl2. Four cell lysis methods were applied to test their compatibility with the pretreatment (prewashing + Ca2+ flocculation) and to ultimately identify the optimal cell lysis method for analyzing fungal communities in forest soils. The results showed that pretreatment with TNP + Triton X-100 + skim milk (100 mM Tris, 100 mM Na4P2O7, 1% polyvinylpyrrolidone, 100 mM NaCl, 0.05% Triton X-100, 4% skim milk, pH 10.0) removed most soil humic contaminants. When the pretreatment was combined with Ca2+ flocculation, the purity of all soil DNA samples was further improved. DNA samples obtained by the fast glass bead-beating method (MethodFGB) had the highest purity. The resulting DNA was successfully used, without further purification steps, as a template for polymerase chain reaction targeting fungal internal transcribed spacer regions. The results obtained by terminal restriction fragment length polymorphism analysis indicated that the MethodFGB revealed greater fungal diversity and more distinctive community structure compared with the other methods tested. Our study provides a protocol for fungal cell lysis in soil, which is fast, convenient, and effective for analyzing fungal communities in forest soils.

Effects of Hybrid surgery on load transfer pattern of cervical spine / 医用生物力学

Objective To investigate the pattern of load transfer in cervical spine treated with Hybrid surgery using total disc replacement (TDR) and spinal fusion, so as to deepen the understanding of Hybrid surgery from the biomechanical view. Methods A finite element model of cervical spine C3-7 (INTACT model) was built to simulate three types of fusion surgeries at C4-6 degenerative segments: upper TDR combined with lower bone graft fusion (TDR45 model), upper fusion combined with lower TDR (TDR56 model), two-level fusion (Fusion456 model). Results In all surgical models, mobility of the fused levels was almost lost, while mobility of the TDR levels increased. Under the axial load of 160 N, the entire cervical motion was less than 4° in the INTACT model, while the motion in the TDR45 model and TDR56 model increased to 8.2° and 8.9°, respectively. In the TDR56 model, the force transferred through the C5 vertebra decreased by 20%, while the force transferred through the facet joint force was 3.8 times larger than that of the INTACT model. The facet contact force in the TDR45 model increased by 50%. The maximal stress in the INTACT model was 0.8 MPa, while the facet contact force in the TDR45 model and TDR56 model were almost 2 times as that in the INTACT model. Conclusions Due to the increased mobility at the TDR levels, the cervical curvature after Hybrid surgery changes greatly under the axial load. The alteration of spinal alignment will result in a decrease in anterior vertebral section force at the operative level, as well as an increase in facet joint force and facet cartilage stress.

Iterative model reconstruction and hybrid iterative reconstruction techniques iDose4 in low-dose abdominal CT: comparison of image quality in evaluation of hypovascular metastases of liver / 中华放射学杂志

Objective To assess the image quality of iterative model reconstruction algorithm (IMR) compared with hybrid iterative reconstruction algorithm (iDose4) for hypovascular hepatic metastases.Methods Medical history and pathological results of 33 cases with primary malignant tumor were retrospective analyzed.Follow-up with enhanced CT or enhanced MRI at more than 3 months confirmed hypovascular metastases in these patients.All patients underwent abdominal CT scanning and dynamic enhanced CT scanning.Portal vein phase of low dose scanning data were taken as the research object.According to the different tube currents and reconstruction algorithm,the images were divided into 4 groups.Group A included images with tube current of 175 mAs and IMR post-processing (17 cases).Group B included images with tube current of 175 mAs and iDose4 post-processing (17 cases).Group C included images with tube current of 125 mAs and IMR post-processing (16 cases).Group D included images with tube current of 125 mAs and iDose4 post-processing (16 cases).In the cases with multiple lesions,the largest lesion was selected to evaluate.For each image of the objective evaluation [including noise,the signal-to-noise ratio (SNR),contrast to noise ratio (CNR)] and subjective evaluation (including lesion sharpness,necrosis interface and diagnostic confidence).The CT dose index of each scanning was recorded.The objective evaluation,subjective evaluation indexes were compared by paired samples t test and Wilcoxon signed rank test.Results The tube current of Group A and Group B were (7.7± 1.8) and (12.8±3.7)HU,while CNR were 10.3 ±2.6 and 5.6± 1.4,SNR were 13.2±3.2 and 8.1 ± 2.2,and the differences were statistically significant (t values were 9.966,12.670,9.203;P＜0.01).The tube current of Group C and Group D were (7.2±1.3) and (9.9±1.8)HU,while CNR were 7.4±2.0 and 3.7±0.9,SNR were 13.9±2.9 and 9.8±1.9,and the differences were statistically significant (t values were 9.209,12.320,9.628;P＜0.01).The lesion sharpness score of Group A and Group B were 4.95±0.24 and 4.29±0.59,while the necrosis interface score were 4.76 ± 0.36 and 3.68 ± 0.30,diagnostic confidence score were 4.94± 0.24 and 4.44 ±0.56,and the differences were statistically significant (P＜0.05).The lesion sharpness score of Group C and Group D were 3.94±0.68 and 3.56±0.63,while the necrosis interface score were 3.91±0.64 and 3.03±0.50,diagnostic confidence score were 4.19±0.40 and 3.94±0.44,and the differences were statistically significant (P＜0.05).CTDIvol of 175 mAs group and 125 m As group were (11.83±0.28) and (8.44±0.24) mGy respectively.Conclusion Compared with iDose4,iterative reconstruction technology IMR significantly reduces the image noise and enhances image quality of hypovascular hepatic metastases.

Modal analysis of human lumbar spine using finite element method / 医用生物力学

Objective To study dynamic characteristics of human lumbar spine using three-dimensional finite element method. Methods Finite element model of lumbar spine (L1~5) was developed and validated based on CT images, and the modal analysis was also conducted. Results A total of top 30-order modal parameters were extracted to obtain dynamic characteristics of the lumbar spine under free boundary conditions. Resonance frequencies of the model were concentrately distributed, but the amplitude of each order varied greatly. Amplitude near L5 segment was much larger, indicating L5 was easily to be injured. This lumbar modal analysis could provide a basis for its further dynamic analysis. Parameters such as natural frequency, modal shape and vibration amplitude of the lumbar spine would be helpful for both lumbar dynamic analysis and optimal design of man-machine interface mechanical equipment.

Biomechanical effects of different traction modes on lumbar spine / 医用生物力学

Objective To study biomechanical effects of the lumbar spine under different traction conditions by using three-dimensional (3D) finite element method. Methods The CT images of lumbar segment L1-5 were input to the Mimics 10.01 for developing 3D geometrical model of L1-5. Then the mesh model of L1-5 was obtained using Geomagic Studio 12.0 and Hypermesh 11.0. The finite element simulation of the lumbar spine under different traction conditions was made by using Abaqus. Results Head-down titling angle was related to the nucleus pulposus stress. When the head-down tilting angle was smaller than 10°, the nucleus pulposus stress regularly changed with the swing cycle; while the head-down tilting angle exceeded 10°, the stress was decreased. In the swing mode, the annulus inner ring stress was increased to promote intervertebral retraction. Conclusions The traction mode helps to relieve the lumbar pain with the swing helping to coordinate the traction effect in each direction, which can better sort out and relieve the rear facet joint disorders. In addition, patients should be careful to select the appropriate traction force in the treatment to achieve good therapeutic effect.

Pilot load analysis under Herbst maneuver based on flight simulation / 医用生物力学

Objective To obtain the multi-axis load histories on physiological coordinate of the pilot when performing Herbst maneuver by flight simulation, and make analysis on the obtained typical data. Methods The 3D geometrical model of the aircraft was established in CAD software based on design parameters of the fourth-generation aircraft, 6 key motion parameters of mass center were obtained by flight simulation, and 3D human body model was developed according to anthropometric measurement data of Chinese male pilot; based on the location of cabin and seat in the aircraft, the assembly model with both the aircraft and human body was established and the multi-axis load histories at different locations of human body under Herbst maneuver were obtained through kinematics analysis of the human-aircraft system. An analytic case of Herbst maneuver at altitude of 3 km and flight velocity of 90 m/s was carried out. Results The load histories at chest, foot and head of human body were basically coincided, but Gy histories between the chest and hand were different; the Gy peak value of hand was about 1.6 g; under the multi-axis loads, the +Gx peak value was about 3.0 g, being the maximum. Conclusions The load histories of aircraft mass center cannot be used as those of human body because it may have some deviation, and the Gy histories for hand cannot be replaced by load histories of other locations on human body when they are used for analysis on effects of multi axis load on operating behaviors of the aircraft.

Biomechanical study on unilateral maxilla restoration using different retention methods / 医用生物力学

Objective To study the biomechanical effects of 3 different retention methods (clasp, attachment or zygomatic implants) on repairing unilateral maxillary defects by using 3D finite element analysis method. Methods The maxillary unilateral defect model was reconstructed by the medical image processing software Mimics. The prosthesis was generated by mirroring technology. After processing, the finite element model of maxillary model by the three different retention methods was established to simulate stress distributions of maxilla during occlusion. Results Compared with the other methods, by using zygomatic implant retention method, stresses on affected and unaffected palate were the largest as 7.399 and 4.864 MPa, respectively, while those on affected and unaffected maxilla were the smallest as 10.46 and 10.86 MPa, respectively. Stress on zygomatic implant itself was 15.25 MPa, which was also the smallest. Conclusions Different retention methods had an obvious impact on unilateral maxillary defect restoration. The clasp and attachment retention methods could share the stress on palate by carrying bracket. The zygomatic implant retention method could also share the stress on maxilla by passing the stress to the zygoma.

Endodontic bacteria from primary and persistent endodontic lesions in Chinese patients as identified by cloning and 16S ribosomal DNA gene sequencing / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Few literatures pertain to the 16S ribosomal DNA (16S rDNA) analysis of bacteria contributing to primary and persistent endodontic lesions, with no information available for the Chinese population. As such, we investigated endodontic bacteria associated with primary and persistent endodontic lesions in adult Chinese patients living in Beijing, China using 16S rDNA gene sequencing techniques.</p><p><b>METHODS</b>Endodontic microbial samples were obtained from fourteen adult Chinese patients and subjected to DNA extraction. Pllymerase chain reaction (PCR) products were cloned and 100 clones from each generated library were randomly selected. Purified plasmid DNA with 16S rDNA gene inserts was sequenced, and the sequences were searched against GenBank databases using the BLASTN algorithm. Only significant identification with the highest-scored BLAST result and 99% minimum similarity was considered for phylotyping.</p><p><b>RESULTS</b>More than 150 taxa were obtained. Primary endodontic infection was mainly associated with Burkholderia cepacia, Actinomyces, Aranicola spp. and Streptococcus sanguinis, whilst Burkholderia cepacia was predominant in the persistent endodontic infections.</p><p><b>CONCLUSION</b>There is a difference in the species profile associated with endodontic infections of Chinese patients living in Beijing in comparison to other geographical or ethnic reports.</p>

Malocclusions in Xia Dynasty in China / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The prevalence of malocclusion in modern population is higher than that in the excavated samples from the ancient times. Presently, the prevalence of juvenile malocclusion in the early stage of permanent teeth is as high as 72.92% in China. This study aimed to observe and evaluate the prevalence and severity of malocclusions in a sample of Xia Dynasty in China, and to compare these findings with the modern Chinese population.</p><p><b>METHODS</b>The material consisted of 38 male and 18 female protohistoric skulls of Xia Dynasty 4000 years ago. Of 86 dental arches, 29 cases had the jaw relationships. Tooth crowding, diastema, individual tooth malposition and malocclusion were studied.</p><p><b>RESULTS</b>Of the samples, 23.3% showed tooth alignment problems including crowding (8.1%), diastema (9.3%), and individual tooth malposition (5.8%). The prevalence of malocclusion was 27.6%, mainly presented as Angle Class I.</p><p><b>CONCLUSIONS</b>It is indicated that over thousands of years from Neolithic Age (6000 - 7000 years ago) to Xia Dynasty (4000 years ago), the prevalence of malocclusion did not change significantly. The prevalence of malocclusion of Xia Dynasty samples was much lower than that of modern population.</p>