三维有限元方法比较二种支抗形式关闭上颌拔牙间隙

目的 :建立关闭上颌第一前磨牙拔牙间隙的上颌骨三维有限元模型 ,比较 2种支抗形式在关闭上颌拔牙间隙时的区别 ,寻找一种安全可靠的加强支抗方法。方法 :应用螺旋CT扫描、计算机图象处理和CAD技术 ,建立关闭上颌第一前磨牙拔牙间隙的上颌骨三维有限元模型。在此基础上分别建立腭部种植体加强磨牙支抗、横腭杆加强磨牙支抗的加载模型。对 2种不同的支抗形式进行有限元分析、比较。结果 :腭部种植体支抗模型中的上颌第一恒磨牙的位移均明显小于横腭杆加强支抗模型 (P <0 .0 1) ,有高度统计学意义。结论 :腭部种植支抗能明显加强磨牙的支抗 ,这种作用优于横腭杆。     

Prediction of calibration curves in ria of digoxin; Influence of some variables

BACKGROUND: Competitive protein binding radioimmunoassay (CPB-RIA) is a principal method for quantifying serum digoxin concentration. The accuracy of this method is critically dependent on factors that influence the substitution reaction between unlabelled (Q) antigen (digoxin) with (125)I-labelled antigen (M) bound to anti-digoxin antibody (P). We studied the influence of initial concentration of M, ionic strength, and viscosity on the substitution reaction between M and Q. In addition, we propose a kinetic model for this reaction. METHODS: We used a commercially available CPB-RIA for digoxin, a gamma counter, and a viscosimeter to study the effect of initial concentration of M, ionic strength, viscosity, and temperature on the substitution reaction between M and Q. Data were analyzed using Statistica software. RESULTS: The apparent rate constant for the reaction between M and Q in the formation of PM is dependent on the initial concentration of M, and the ionic strength, viscosity, and temperature of the reaction medium, and independent of the concentration of Q. CONCLUSION: A kinetic model for the displacement of the (125)I-digoxin by the digoxin in its union to a specific antibody is proposed. Such model adjusts satisfactorily to the results and allows the prediction of the calibration curves of RIA (activity bound to the antibody vs. concentration of digoxin) showing the influence of the concentration of both species, the time of incubation, the viscosity and the ionic strength of the medium, on the sensitivity of the method of RIA on which the analytical determination of the digoxin is based.     

神经根沉降征与腰椎间盘突出症的相关性研究

目的 探讨神经根沉降征与腰椎间盘突出症(LDH)的相关性及其对腰椎间盘突出症患者保守治疗效果的预判作用。 方法 选取68例L4/5椎间盘突出患者作为研究对象,按神经根沉降征是否阳性分为A组(阳性组)36例,B组(阴性组)32例。对A、B两组患者进行年龄、性别、病程、硬膜囊受压面积比及VAS评分、JOA评分比较。再予以两组患者相同的保守治疗1个月,观察两组疗效是否存在差异。 结果 两组患者的性别、年龄及病程的比较差异无统计学意义(P均>0.05);两组患者的硬膜囊受压面积比差异有统计学意义(P<0.05),A组病例整体的硬膜囊压迫程度较B组重,当硬膜囊受压面积比>25%时,出现阳性神经根沉降的病例明显增多;两组间治疗前VAS评分、JOA评分比较差异无统计学意义(P>0.05);治疗后两组VAS评分比较,差异无统计学意义(P>0.05),JOA评分比较,治疗后B组JOA评分高于A组(P<0.05);两组VAS的显效率比较差异无统计学意义(P>0.05),两组JOA的显效率比较,差异有统计学意义(P<0.05),提示B组疗效优于A组。 结论 神经根沉降征阳性与阴性患者的性别、年龄、病程及VAS评分、JOA评分无差异;硬膜囊受压面积越大,神经根沉降征阳性率越高。神经根沉降症阳性的LDH患者保守治疗效果较阴性者差,提示神经根沉降征可能作为一个预测LDH患者保守治疗效果的指标。     

急性心肌梗死局部室壁峰值速度和位移的变化

目的观察组织速度峰值（Sm）和组织位移峰值（D）在急性心肌梗死相关动脉（IRA）供血节段与非梗死相关动脉（NIRA）供血节段急性期的变化,并与正常人相应节段比较,探讨Sm和D能否敏感地评估缺血心肌、坏死心肌。方法以31例首次发病的急性心肌梗死（AMI）患者为研究对象,其中前壁AMI 14例,IRA为前降支（LAD）;下壁AMI 17例,IRA为回旋支（LCX）10例,IRA为右冠状动脉（RCA）7例;所有患者均在发病24小时内获取其标准心尖二腔、长轴、四腔彩色组织多普勒,描记心肌各节段的TVI、TT曲线,测量基底段、中段、心尖部收缩相峰值。并与42例正常人对照分析。结果AMI患者的Sm和D与正常人比较结果显示：在前壁和前间隔所有IRA基底段、中段和部分NIRA基底段、中段峰值减低有显著或极显著的统计学差异（P〈0.001或P〈0.01、P〈0.05）,峰值减低程度IRA大于NIRA;在侧壁、下壁、后壁和室间隔所有NIRA基底段、中段和部分IRA基底段、中段峰值减低有显著或极显著的统计学差异（P〈0.001或P〈0.01、P〈0.05）,峰值减低程度NIRA大于IRA。AMI患者的Sm和D在IRA和NIRA比较提示我们,在前壁AMI组（除外前壁的Sm）,前壁和下壁的基底段、中段的Sm和D可以区分梗死与非梗死心肌（P〈0.05）;在下壁AMI组（除外下壁AMI患者的Sm）侧壁、前间隔、后壁和室间隔中段的Sm和D可以区分梗死与非梗死心肌（P〈0.05）。结论AMI患者的Sm和D与正常人比较不仅能够在急性缺血早期无创、定量、准确、敏感地区分正常及缺血、坏死心肌,也能够评估IRA和NIRA的缺血、坏死心肌,为临床提供了可床旁测量、方便快捷的诊疗手段。     

经皮侧后路椎间孔镜下髓核摘除术治疗青少年腰椎间盘突出症的疗效与安全性分析

[目的]探讨经皮侧后路椎间孔镜下髓核摘除术治疗青少年腰椎间盘突出症的疗效与安全性.[方法]选自本院于2013年5月至2015年5月期间收治的青少年腰椎间盘突出症患者72例.依据随机数字表法分为观察组和对照组,各36例.对照组采用传统手术方法治疗,观察组采用经皮侧后路椎间孔镜下髓核摘除术治疗.[结果]观察组治疗总有效率(86.11％)高于对照组(63.89％)(P<0.05);观察组手术切口长度短于对照组,术后下床活动时间快于对照组,住院时间短于对照组,手术时间短于对照组,均有统计学差异(P<0.05);两组VAS评分术后3d、术后1个月、术后6个月、术后12个月下降(P<0.05);观察组VAS评分术后3d、术后1个月、术后6个月、术后12个月低于对照组(P<0.05);两组JOA评分术后3 d、术后1个月、术后6个月、术后12个月增加(P<0.05);观察组JOA评分术后3 d、术后1个月、术后6个月、术后12个月高于对照组(P<0.05).[结论]经皮侧后路椎间孔镜下髓核摘除术治疗青少年腰椎间盘突出症的疗效显著,安全性良好,具有重要研究意义.     

下胫腓联合损伤模型复位的压力与位移变化的生物力学研究

目的　探讨下胫腓联合损伤复位施加压力与位移变化的关系,探索最佳复位力度。 方法　选取10例新鲜冻融尸体小腿标本,解剖下胫腓联合复合体,依次切断下胫腓联合前方结构（下胫腓前韧带）、后方结构（下胫腓后韧带和下胫腓横韧带）,以及下胫腓联合上方10 cm的骨间膜,在同一标本上建立不同程度的下胫腓损伤模型,每个模型分别接受CT扫描,通过Mimics软件测量外踝嵴（A）和内踝表面中心（B）在不同模型中的距离。循AB连线方向复位,记录位移与压力大小的关系。 结果　分别切断下胫腓前联合、前后联合、前后联合及上方10 cm骨间膜后,AB平均距离均有增大,与下胫腓联合完整时差异有统计学意义,P<0.05;但每组损伤模型间AB距离对比无明显统计学差异,P>0.05。使用生物力学压力测试仪测出下胫腓解剖复位所需压力为40~70 N。下胫腓前后联合断裂复位所用压力与单纯下胫腓前联合断裂复位对比差异无统计学意义,P>0.05。下胫腓前后联合及上方10 cm 骨间膜断裂复位所用压力与下胫腓前后联合断裂复位对比差异无统计学意义,P>0.05;但与单纯下胫腓联合前韧带断裂复位对比差异具有统计学意义,P＜0.05。 结论　下胫腓联合不同程度损伤后,下胫腓之间分离的距离较完整时存在显著性差异,需用不同大小的力量进行复位。     

小鼠颈脊髓半侧挫伤模型的建立及其组织学特点

目的　建立基于位移控制的C57/6J小鼠C5脊髓半侧挫伤模型,观察其脊髓组织学改变。 方法　C57BL/6小鼠在麻醉状态下行C5左侧椎板切除术,打击头（直径0.75 mm）对准C5左侧,由电磁伺服材料试验机驱动挫伤脊髓,设定打击位移0.9 mm,打击速度50 mm/s。损伤后1周脊髓标本取材,EC染色,作组织学定量分析。 结果　打击参数结果稳定性与重复性良好。打击位移、打击速度和打击力分别为（0.880±0.035）mm、（48.146±4.367）mm/s、（0.407±0.129）N,损伤中心的脊髓组织学表现为：伤侧脊髓有明显的出血及正常组织结构破坏,脊髓背侧束、脊髓后角和部分前角有破坏;健侧脊髓结构基本保持完整。计算损伤中心平面的残存灰质比例、残存白质比例及损伤面积比例分别为（19±7）%、（88±9）%及（28±4）%。 结论　本研究成功建立小鼠颈脊髓半侧挫伤模型,此模型具有重复性较好的力学参数,表现出典型的单侧颈脊髓损伤的组织学特征,可为脊髓损伤分子机制和治疗研究奠定基础。     

ECG-gated, mechanical and electromechanical wave imaging of cardiovascular tissues in vivo

In simplistic terms, the motion of the heart can be summarized as an active contraction and passive relaxation of the myocardium. However, the local motion of cardiovascular tissues over the course of an entire cardiac cycle results from various transient events such as the valves closing/opening, sudden changes in blood pressure and electrical conduction of the myocardium. The transient motion generated by most of these events occurs within a very short time (on the order of 1 ms) and cannot be imaged correctly with conventional imaging systems, due to their limited temporal resolution. In this paper, we propose a method for imaging this rapid transient motion of tissues in cardiovascular applications. Our method is based on imaging tissues with ultrasound at high frame rates (up to 8000 fps) by synchronizing the two-dimensional (2D) image acquisition on the electrocardiogram (ECG) signals. In vivo feasibility is demonstrated in anesthetized mice. The propagation of several transient mechanical waves was imaged in different regions of the myocardium and the wave phase velocities were found to be between 0.44 m/s and 5 m/s. These waves may be generated by either a purely mechanical effects or through electromechanical coupling in the myocardium depending on the phase of the cardiac cycle, in which they occur. The abdominal aorta was also imaged using the same technique and the propagation of a mechanical pulse wave was imaged. The pulse wave velocity was measured and the Young's modulus of the vessel wall was derived based on the Moens-Korteweg equation. This method could potentially be used for mapping the stiffness of the myocardium and the artery walls and may lead to the early diagnosis of cardiovascular diseases.     

腰椎间盘突出并椎体后缘离断症的CT诊断

目的：探讨腰椎间盘突出并椎体后缘离断症的发病机理和CT表现，提高对本症的认识。材料与方法：对16例患者进行轴位及部分冠、矢状位重建的CT扫描。结果：本组病例离断骨片均来自椎体后上缘，以S1居多，后移骨片前方骨质缺损区为间盘组织充填，周边硬化。结论：椎体后缘骨片离断的主要发病机理是椎间盘突出的推压，为继发改变，认同腰椎间盘突出并椎体后缘离断症的命名。     

Mini suture anchor: An effective device for reduction and fixation of displaced temporomandibular joint disc with intracapsular condylar fracture

PurposeThe main aim is to provide clinical reference for the application of mini suture anchor in the reduction and fixation of displaced temporomandibular joint (TMJ) disc with intracapsular condylar fracture.MethodsFrom October 2018 to October 2019, 21 patients (31 sides) with intracapsular condylar fractures and articular disc displacement from West China Hospital of Stomatology, Sichuan University were included. The selection criteria were: (1) mandibular condylar fractures accompanied by displacement of the TMJ disc, confirmed by clinical examination, CT scan and other auxiliary examinations; (2) indication for surgical treatment; (3) no surgical contraindications; (4) no previous history of surgery in the operative area; (5) no facial nerve injury before the surgery; (6) informed consent to participate in the research program and (7) complete data. Patients without surgical treatment were excluded. The employed patients were followed up at 1, 3, 6 and 12 months after operation. Outcomes were assessed by success rate of operation, TMJ function and radiological examination results at 3 months after operation. Data were expressed as number and percent and analyzed using SPSS 19.0.ResultsAll the surgical procedures were completed successfully and all the articular discs were firmly attached to the condyles. The articular disc sufficiently covered the condylar head after the fixation. The fixation remained stable when the mandible was moved in each direction by the surgeons. No complications occurred. The functions of the TMJ were well-recovered postoperatively in most cases. CT scan revealed that the screws were completely embedded in the bone without loosening or displacement.ConclusionMini suture anchor can provide satisfactory stabilization for the reduced articular disc and also promote the recovery of TMJ functions.