非线性三维有限元法分析腰椎间盘退变

目的 探讨椎间盘退变对腰椎活动节段生物力学的影响.方法 采用新型的基于CT图像的CAD建模方法精确建立L4-L5运动节段的三维非线性有限元模型,并通过改变椎间盘材料特性和椎间盘高度等参数,建立正常椎间盘模型和轻、中、重度椎间盘退变模型,分别对4种有限元模型进行生物力学测试,比较4种模型之间刚度、髓核内压、后部结构力、纤维环基质最大应力的差异,并比较椎体、终板的应力分布变化.结果 各种载荷条件下,退变椎间盘模型刚度均与正常椎间盘模型不同,其中轻度退变模型刚度小于正常模型,而中度退变模型和重度退变模型刚度大于正常模型,且重度退变模型刚度大于中度退变模型;与正常模型比较,轻度退变模型的后部结构力略有增大,而中度退变和重度退变模型的后部结构力逐渐减小;随着椎间盘退变程度的增加,髓核内压逐渐减小,纤维环基质最大von Mises应力渐行性增大,各指标在5种载荷下表现一致;随着椎间盘退变的加重,椎间盘承载向纤维环分散,椎体、终板外缘出现应力集中现象.结论 椎间盘退变可导致腰椎活动节段刚度改变,轻度椎间盘退变引起腰椎刚度下降,而中、重度椎间盘退变时腰椎刚度增加;椎间盘退变时腰椎间盘承载与腰椎后部结构力呈现负相关变化;退变椎间盘的承载模式发生改变,椎间盘、椎体、终板应力分布存在向外周扩散的趋势.     

正常人体颈椎间盘的三维有限元分析

目的：研究下颈椎间盘三维有限元模型的建立及其应力分布情况.方法：通过CT扫描、Unigraphics V18.0 软件进行影像边界记录、定标等方法,按照点、线、面、体的顺序重建三维结构,采用CAD数据处理技术,输入相关的材料特性,构建下颈椎间盘三维有限元模型.结果：正常椎间盘纤维环在人体直立位、前屈位和后伸位时应力明显集中于后侧与后外侧,平均应力以后伸位最高.当椎间盘变性后,纤维环的平均应力水平比正常时显著降低.结论：建立颈椎间盘三维有限元模型并进行应力分析是可行的,且结果可信.     

腰椎间盘退变后应力变化的有限元分析

目的 利用有限元分析方法,评估腰椎间盘退变后的生物力学变化.方法 利用MIMICS软件对正常腰椎的CT图像进行预处理后,导入ABAQUS软件建立正常椎间盘L3～L4节段的三维有限元模型.通过改变椎间盘退变后对应的材料属性,建立退变椎间盘L3～L4节段的有限元模型.对模型施加0.3 MPa均布轴向压缩载荷,比较正常和退变椎间盘的纤维环、髓核、软骨终板、关节突关节的应力.结果 与正常椎间盘比较,退变椎间盘的应力分布发生改变,纤维环周边承受较大应力,髓核的压应力明显降低,软骨终板的应力集中在外周偏后;关节突关节面的应力明显增大.结论 有限元方法可以直观地观察椎间盘退变对腰椎的影响,是对临床研究的必要补充.     

模拟腰部推拿手法三维有限元模型分析

目的：应用三维有限元模型研究模拟腰部推拿手法时腰椎内部结构变化。方法：使用ABAQUS6．1有限元软件建立腰椎L4－5有限元模型，分别模拟斜板手法、坐位旋转和牵板手法的条件。结果：模拟手法作用时间椎间盘内髓核内压力坐位旋围手法最高，牵扳手法最低为负值。三种手法小关节合力无明显差别；斜扳手法和坐位旋转手法外层纤维环应力最大，牵扳手法内层纤维环应力最大，三种手法在椎间盘的后外侧均有位移。结论：应用三维有限元模型可以很好的模拟各种腰部推拿手法的状态，并可以得到与生物力学实验基本一致的结果。     

腰椎间盘摘除新型三维有限元模型研究

目的 建立腰椎L4/5运动节段椎间盘摘除的三维有限元模型,用于进一步的生物力学研究.方法 将CT扫描的腰椎图像结合人体解剖学数据通过3DSMAX建模形成正常中国男性L4/5运动节段的三维模型,用有限元分析软件SAP2000转换成三维有限元模型.去除模型中L4～5椎间盘右后侧1/4的纤维环中部全层及约1/4的髓核单元,以模拟腰椎间盘摘除手术.结果 建立了L4/5运动节段椎间盘摘除的三维有限元模型.结论 通过CT断层扫描、图像数字化处理及计算机辅助设计等方法,可以建立腰椎运动节段椎间盘摘除的三维有限元模型,用于脊柱生物力学的研究.     

不同体位下推拿旋转手法对颈椎间盘有限元模型应力分布的影响

目的探讨不同体位下推拿旋转手法对颈椎间盘有限元模型应力分布的影响,为其临床应用奠定基础。方法采集1例健康男性志愿者的CT和MRI数据,以逆向工程软件Geomagic Studio 12. 0建立颈椎间盘有限元模型,并分别模拟前屈30°、中立位和后伸30°三个体位予以旋转推拿的力学载荷,Ansys 13. 0软件计算不同体位的力学载荷下颈椎间盘有限元模型髓核应力分布和位移变化。结果本次研究建立颈椎C4/C6有限元模型,共包括19 255个节点,96 275个单元,C4/C5、C5/C6的屈曲、伸直、侧弯、旋转力矩与实验模型的符合程度相对满意。前屈30°、中立、后伸30°三种不同体位下,椎间盘的内在应力分布均集中在纤维环,髓内压变化幅度小于纤维环,但与纤维环变化趋势基本一致,髓核位移与髓内压变化基本一致。退变的椎间盘模型在静止生理状态时便有髓核位移情况,施加旋转手法后,髓内压和髓核位移均有所增大,其中C4/C5、C5/C6髓内压和髓核位移在后伸30°位时最小,其次是中立位,前屈30°位最大。结论颈椎间盘有限元模型分析结果支持后伸30°位时旋转手法对颈椎间盘髓核影响较小,安全性高。     

纤维环穿刺法建立兔腰椎间盘退变模型

目的 建立纤维环穿刺法建立兔椎间盘退变模型。方法 40只新西兰大白兔随机分为牵引组和对照组,手术组（30）只以16G针刺损伤新西兰兔腰椎椎体右前侧纤维环制备椎间盘退变模型,对照组（10只）不予穿刺手术。分别于造模术后4、8、12周通过腰椎侧位X片及组织病理学检查观察椎间隙变化情况及组织病理情况。结果 手术组在腰椎侧位X线片上术后4周椎间隙高度逐渐下降,椎间盘高度指数变化率（DHI）2组差异有统计学意义（P<0.05）;且随着时间的推移,手术组椎间盘内细胞逐渐减少。结论 纤维环穿刺法可缓慢模拟人类损伤后椎间盘退变,操作安全可靠。     

不同工况对腰椎运动节段作用的三维有限元模型分析

目的：研究各种工况条件下腰椎活动节段的三维有限元模型。方法：使用ABAQUS6．5有限元分析软件建立L4-5运动节段的三维有限元模型,分析腰椎运动节段在屈曲、拉伸、侧屈及旋转扭矩作用力下各部结构的应力变化。结果i压缩时椎体密质骨、椎弓根、椎弓峡部和后部小关节部应力最高;拉伸时小关节出现应力集中,高于其他部分;侧屈时屈侧椎体、后部小关节及椎间盘部为应力集中,拉伸侧呈张应力;轴向旋转时后部小关节及椎间盘后部应力较高;屈曲加旋转时椎体及椎间盘前缘、后部小关节处出现应力集中。结论：应用有限元分析能形象模拟腰椎活动节段各种载荷下的应力分析,不同运动条件下,腰椎运动生理节段的应力集中部位不同。这是中医旋转复位手法治疗腰椎小关节紊乱和腰椎间盘突出症的力学依据之一。     

两种坐位旋转手法腰椎应力及位移的有限元分析

摘要：目的 探讨两种坐位旋转手法的作用机理及其合理性、安全性。 方法 使用螺旋CT,以1mm的间隔,对1具男性青年新鲜尸体的腰椎标本沿轴向进行断层扫描,以jpg格式将其断面图像输入计算机。利用三维重建软件Minics建立腰椎三维计算机模型。根据手法原理,将两种坐位旋转手法进行分解,把力学参数带入三维有限元模型,利用Ansys 9.0 软件进行计算。结果 椎间盘: 两种手法椎间盘的应力都主要集中于纤维环,尤其是外层纤维环,髓核应力相对较小。两者的最大位移分布基本一致,都位于椎间盘的左侧。椎间盘后部位移也都以左侧明显。椎体及后部结构: 直腰旋转手法主要应力分布于小关节,腰椎定点旋转手法主要应力分布与椎体峡部、椎弓根侧隐窝及上位椎体小关节面的下端。两者的最大位移分布不同,直腰旋转手法最大位移位于L4棘突,腰椎定点旋转手法最大位移位于L4椎体上缘左侧及L4左侧上关节突;且腰椎定点旋转手法的椎间孔位移更显著。结论 手法造成了椎间盘、关节突的位移,有利于解除神经根的粘连。两种手法比较,脊柱定点旋转手法更具有效性及安全性。     

腰椎间盘突出症两种常规手术对椎间盘压应力影响的实验研究

目的：分析不同腰椎间盘突出症手术对邻近椎间盘变性的影响，为手术方法的选择和改进提供依据。方法：采用30具新鲜小牛腰椎标本，制成两种腰椎间盘突出症的手术模型(椎板间开窗、全椎板切除)，模拟人体载荷前屈和侧屈运动，测量邻近椎间盘的压应力，并与正常对照组的椎间盘压应力进行比较。结果：在前屈和侧屈运动中不同手术对邻近椎间盘压应力的影响有着不同程度的差异。结论：后路椎板开窗术具有创伤小，对手术区城和邻近节段的干扰及稳定性影响较轻微，可作为多数腰椎间盘突出症治疗的选择；而全椎板切除对手术邻近节段的干扰和稳定性的影响较大，应严格掌握其手术适应症。     

Value of D-Dimers in patients with acute aortic dissection

Objective: To evaluatel the value of D-dimers in patients with acute aortic dissection (AAD). Methods: This study consisted of 16 patients with AAD and 27 non-AAD patients. Serum D-dimets were measured by Sta-Liatest D-DI immunoturbidimetric assay. Results: D-dimer level was higher (P ＜ 0.001) in patients with AAD(7.91 ± 5.52 μg/ml) than that in non- AAD group(1.57±1.24 μg/ml). D-dimer was positive (＞0.4 μg/ml) in all patients with AAD and in 10 control group patients (37%). Among patients with acute AAD, D-dimers tended to be higher in Stanford A than in Stanford B (8.67 ± 4.31 μg/ml vs. 3.24±1.27 μg/ml, P ＜0.01). D-dimer values tended to be higher in more extended disease(3.84 ± 1.65 μg/ml, 8.57 ± 3.58 μg/ml and 11.87 ± 5.69 μg/ml in thoracic aorta, thoracic and abdominal aorta, thoracic and abdominal aorta and iliacal arteries, respectively, P ＜ 0.05 for both 8.57 ± 3.58 and 11.87 ± 5.69 vs. 3.84 ± 1.65 ). Including the control group into the analysis, we found a sensitivity of 100%, a negative predictive value of 100%, and a specificity of 66% and a positive predictive value of 64% for D-dimer in diagnosis of AAD in our patients with suspected AAD. Conclusion: D-dimer was elevated in patients with AAD. A negative D-dimer test result could be useful in excluding AAD.     

Research of combined liver-kidney transplantation model in rats

Objective： To set up a simple and reliable rat model of combined liver-kidney transplantation. Methods： SD rats served as both donors and recipients. 4℃ sodium lactate Ringer＇s was infused from portal veins to donated livers,and from abdominal aorta to donated kidneys, respectively. Anastomosis of the portal vein and the inferior vena cava （IVC） inferior to the right kidney between the graft and the recipient was performed by a double cuff method, then the superior hepatic vena cava with suture. A patch of donated renal artery was anastomosed to the recipient abdominal aorta. The urethra and bile duct were reconstructed with a simple inside bracket. Results： Among 65 cases of combined liver-kidney transplantation, the success rate in the late 40 cases was 77.5%. The function of the grafted liver and kidney remained normal. Conclusion： This rat model of combined liver-kidney transplantation can be established in common laboratory conditions with high success rate and meet the needs of renal transplantation experiment.     

BLOOD PRESSURE CHANGE WITH AGE IN SALT-SENSITIVE TEENAGERS

Objective To observe blood pressure change with age in salt-sensitive teenagers whose salt sensitivity were determined by repeated testing.Methods Salt sensitivity was determined through intravenous infusion of normal saline combined with volume-depletion by oral diuretic furosemide in 55 teenagers. After five years, salt sensitivity was re-examined and subject blood pressure was followed up. Blood pressure changes in salt-sensitive teenagers were compared to that of non-salt sensitive teenagers over five years.Results After 5 years, the repetition rate of salt sensitivity determined by intravenous saline loading is 92.7%. In teenagers with salt sensitivity on the baseline, both the systolic blood pressure increments and increment rates were much higher than non-salt sensitive teenagers (12.7±12.1 mmHg vs. 2.8±5.2 mmHg, P＜ 0.01; 12.2%± 12.0% vs. 2.5% ±4.4%, P＜ 0.001,respectively). There was a similar trend for diastolic blood pressure (8.4 ± 6.4 mmHg vs. 3.7 ± 6.4 mmHg, P = 0.052; 13.2% ±10.6 % vs. 6.8%± 10.1%, P = 0.053, respectively).Conclusions Salt sensitivity determined by intravenous saline loading showed good reproducibility. Blood pressure increments with age were much higher in salt-sensitive teenagers than non-salt sensitive teenagers, especially in terms of systolic blood pressure.     

安心颗粒对急诊经皮冠状动脉介入术后生活质量影响的研究

目的：评价使用安心颗粒对急诊经皮冠状动脉介入术（PPCI）术后生活质量的影响.方法：将160例接受PPCI的急性ST段抬高型心肌梗死患者随机分为安心颗粒组（术前顿服安心颗粒8.8g,术后安心颗粒4.4 g/次,每日2次）和对照组（仅接受基础药物治疗）.所有患者均服用阿司匹林、氯吡格雷和阿托伐他汀.分别在入院时、出院前1d、出院后180 d时,应用心肌梗死多维度量表（MIDAS）、中文版SF-36评价量表对患者生活质量评分.并观察术后30 d以内的出血并发症、血小板减少症发生情况.结果：入院时和出院前1d,两组患者的心肌梗死MIDAS、SF-36量表评分比较无差异（P＞0.05）;出院后180 d时,与对照组比较,安心颗粒组MIDAS、SF-36评分明显减低（P＜0.05）;组内与入院时比较,两组出院前1d、出院后180 d时,MIDAS、SF-36评分均降低（P＜0.05）.两组患者在随访期间均无大量出血、少量出血、重度和极重度血小板减少症发生,安心颗粒组有4例、对照组有7例发生不明显出血（P＞0.05）.两组发生轻度血小板减少症的患者数比较无差异（P＞0.05）.结论：PPCI使用安心颗粒,能改善急性ST段抬高型心肌梗死患者的生活质量,且不增加出血风险.     

The comparative studies of the influences of Urapidil and Nicardipine on sino-atrial node function, atrio-ventricular node function and hemodynamics

Objective:To investigate the influences of urapidil and nicardipine on rabbit sinus function,atrio-ventricular node function and hemodynamics.Methods:Thirty-two Angora's rabbits were selected and randomly divided into four groups.U1 group:urapidil 0.25 mg/kg;U2 group:urapidil 0.5 mg/kg;N1 group:nicardipine 10 μg/kg;N2 group:nicardipine 20 μg/kg.All these medicine were administrated within 30 seconds.Measurements were taken before and after the administration of urapidil or nicardipine for the following data:mean blood pressure(MAP),heart rate(HR),sino-atrial conduction time(SACT),maximal sinoatrial recovery time(SNRTmax)corrected sinus node recovery time(CSNRT),index of sinus node recovery time(SNRTI),Wenckebach A-V conduction frequency (WB),and P-R interval.Results:Significant MAP and HR changes were identified in all of the four groups before and after administration of both urapidil and nicardipine.No significant changes could be found in the rest of the parameters.Intergroup analysis showed that SACT and CSNRT of N1 and N2 groups were shorter than those of the U2 group(P＜0.01);the MAP decreased(P＜0.01)and the HR increased drastically(P＜0.01).Conclusions:Neither urapidil(0.25 mg/kg,0.5 mg/kg)nor nicardipine(10μg/kg,20μg/kg)has any significant influence on rabbit sinus function or rabbit atrio-ventricular node function.Nicardipine could be a better choice than urapidil for parafunctional sinus node patients.     

Expression of OPGmRNA and ODFmRNA in the patients of hip fracture due to osteoporosis

Objective：To investigate the gene expression of osteoprotegerin（OPG） and osteoclast differentiation factor（ODF） in the bone tissue of patients with hip fracture due to osteoporosis. Methods：OPGmRNA and ODFmRNA in the bone tissue in 50 cases of osteoporosis sufferers（over 50 years old） with hip fracture（Observer Group） and 30 cases of hip facture sufferers with no osteoporosis（Control group） were analyzed with the Semi-Quantitative RT-PCR method. Results：The mRNA expressed of ODF, OPG were both high in the patients with hip fracture. In the control group, the expression of OPG mRNA was observed, while the expression of ODF mRNA was very slight. Conclusion：Aged patients contained all signals including OPG, ODF that are essential for inducing osteoclastogenesis and promoting bone resorption.     

Dynamic Changes in Serum Estradiol and Progesterone levels in Patients of Premenstrual Syndrome with Adverse Flow of Liver-qi

Objective:To probe into the influence of changes of ovarian hormones on the pathogenesis of the specific sub-type premenstrual syndrome(PMS)and reveal partial microcosmic mechanisms of adverse flow of liver-qi.Methods:Estradiol(E2)and progesterone(P)levels in serum were determined at different phases of menstrual cycle by radioimmunoassay.Results:In the group of PMS with adverse flow of liver-qi.the secretive peak value Of E2 and P at the follicular phase significantly decreased,and the secretive peak value at the luteal phase did not come into being.Conclusions:Low E2 and P secretive peak at the follicular phase and absence of secretive peak at the luteal phase is one of the microcosmic mechanisms of PMS with adverse flow of liver-qi.One of the pathophysiologic mechanisms of specific sub-type PMS is probably the continuous low level of E2and P.     

Real-time Three-dimensional Echocardiography in Assessment of Left Ventricular and Right Ventricular Volumes

Real-time three-dimensional echocardiography (RT3DE)is a new ultrasound technique that enables dynamic threedimensional visualization and quantification of the heart in real time. Investigation of feasibility and methodology of RT3DE in determining left ventricular (LV) and right ventricular (RV) volumes, RT3DE was performed in 35 normal adults using Philips SONOS 7500 system with a 2-4 MHz matrix array transducer. The 60°×60° "pyramid" volume database was obtained and analyzed on a TomTec echo workstation. Both LV and RV volumes were calculated with four 3DE methods (i.e. apical 2, 4, 8, and 16-plane) through manually tracing ventricular endocardial borders in end diastole and end systole. Stroke volumes were then calculated. LV volume was also measured by 2DE Simpson's rule using GE VIVID 7 ultrasound machine.     

SCREENING FOR A 21-CHROMOSOME ABNORMALITY IN PREIMPLANTED EMBRYOS OF ELDERLY WOMEN

Increasing maternal age is the only etiological factor unequivocally linked to Down's syndrome in humans. The occurrence rate of newborns with Down's syndrome is about 1/220 in women over 35 years old. However, the occurrence rate in embryos fertilized in vitro, of the elder woman is unclear. Using FISH we screened the number of chromosome 21 in preimplanted embryos of 5 elderly women (average age, 38.4 years) to study the feasibility and necessity of screening trisomy 21 in embryos in patients over 35 years old at the in vitro fertilization (IVF) center.     

Scientific principles and rigorous processes should be followed in developing clinical guidelines for therapeutic interventions of integrative medicine

A clinical guideline for the therapeutic interventions of integrative medicine may be defined as a written document which states a series of recommendations on therapeutic interventions of integrative medicine for a special disease or condition. The guideline may provide assistance to medical professionals in making clinical decisions aimed at improving the clinical outcome of patients and reducing the costs of medical care（~＇4~. Recommendations issued by a guideline should be based on the best available evidence in both Western and Chinese medicine. For fulfilling this purpose, the development of clinical guidelines for therapeutic interventions in the field of integrative medicine should follow scientific principles and undergo a rigorous processes.