胫骨平台骨折术后高度丢失的原因及对策

目的分析随访病例术后平台高度丢失的原因并提出对策,提高胫骨平台骨折手术解剖复位率。方法对2000年1月～2003年6月期间在我院治疗的不同类型胫骨平台骨折进行回顾,对有良好随访的57例达解剖复位或接近解剖复位的平台骨折病例进行X线片分析。结果随访6个月～2.5年,平均15个月,约有28.1%发生平台高度丢失(判定标准:关节面塌陷>3mm和/或轴向对线不良>5°),总结出6种胫骨平台骨折术后高度丢失的原因:①年龄>60岁,②严重骨质疏松,③复杂性、粉碎性骨折,④拉力螺钉、T或L型钢板抗剪应力较差,⑤植骨不充分,⑥过早负重。结论术前正确判断骨折类型、足量植骨、解剖复位后坚强内固定及早期不负重功能锻炼是减少平台高度丢失、提高胫骨平台骨折疗效的关键。在胫骨平台骨折手术复位及术后康复锻炼中,如能充分考虑上述六种造成平台高度丢失的原因并加以克服,将可能避免或延缓创伤性骨关节炎的发生。     

胫骨结节下移对髌股关节影响的实验研究

作者用4只成年犬,将胫骨结节下移约0.5cm,克氏针固定,其可引起髌骨下移,造成髌股关节间关节面接触出现错格现象,接触面积减少和关节间作用力增加,使关节软骨受到机械性损害和营养障碍,出现关节软骨的退行性改变。     

载物台自动式彩色电视显微镜

在电视显微镜上安装一组步进电机能实现自动粗调焦和等距移动标本。用8031单片机应用系统控制步进电机的运转，在功率放大器中选用IRF530场效应管以提高系统的性能和可靠性。这种显微镜与微机组合，构成普及型显微图象处理系统的硬件基础。     

Combined analysis of spatial and velocity displacement artifacts in phase contrast measurements of complex flows

MR phase contrast (PC) velocity imaging is a promising tool for quantifying blood flow velocity in vivo. PC velocity imaging is, however, susceptible to artifacts that result from the displacement of spins during the finite duration pulse sequences. Such displacement artifacts can lead to errors in velocity measurements, especially in the presence of oblique and accelerating flows, which are common throughout the cardiovascular system. By tracking particles (representing spins) through a computed velocity field, and assuming that spatial and velocity encodings occur at discrete times during the pulse sequence, we simulate the separate and combined effects of oblique and acceleration artifacts on PC velocity images. We demonstrate, both by simulation and MR measurement, the errors associated with such artifacts in PC velocity measurements in a representative flow geometry. Using example particle trajectories, we provide a fluid dynamic basis for characteristic phase-velocity image distortions that can arise when imaging complex, physiologically relevant flows.     

踝关节骨折的治疗与术后功能评估

自1993年到1995年,我科连续收治了75例不稳定闭合性踝关节骨折病例,术后进行了平均2.3年的随访,结果59例参加随访者临床评估优良率为81.36%,与国外有关资料相似。术后评分与术后复位程度、损伤类型等相关。对于评估分值低于80分,严重影响生活质量者,可考虑行踝关节融合术。不能保证坚强内固定者,术后患踝必须制动及避免负重6周。     

Aggression induced by intermittent positive reinforcement

Mammalian and non-mammalian species engage in aggressive behavior toward animate and inanimate targets when exposed to intermittent access to a positive reinforcer. This behavior, called extinction- or schedule-induced aggression, typically includes a biting or striking topography that inflicts damage on a target. This paper critically reviews research and theoretical issues concerning such aggression and suggests directions for future investigation.     

预防实验家兔肉膜和深筋膜植入扩张器移位方法的改进

目的探讨预防兔肉膜和深筋膜植入扩张器移位的方法。方法普通级实验家兔40只,随机分为两组,即实验组20只和对照组20只。在其一侧背部皮肤肉膜深面自切口潜行分离形成植入腔穴,在腔穴周边,用3-0丝线间断缝合肉膜、深筋膜,植入50 m L肾形硅橡胶软组织扩张器。术后1周,用文刺机在扩张器周围四点做黑色文刺,用来标记扩张器位置。实验组术后2个月开始注水直至达到总量140 m L;对照组术后1周开始注水直至达到总量140 m L。分别观察和记录实验组和对照组扩张器在注水期间是否移位、切口是否裂开、注射壶是否翻转等并发症,以及动物的死亡率。结果实验组中没有兔子发生扩张器移位,对照组存活动物中有4只兔子发生扩张器移位,两组扩张器移位相比较,差异具有统计学意义﹙P0.05﹚;实验组兔子扩张期切口裂开发生率虽然低于对照组,但两组比较没有统计学意义﹙P0.05﹚;同时两组扩张器在注水壶翻转率、感染率及动物死亡率方面相比较都无统计学意义﹙P0.05﹚。结论分离腔隙内固定加上延迟扩张的手术方法可有效预防兔肉膜与深筋膜之间的扩张器移位,实现有效扩张。     

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.     

3种游离端附着体义齿基牙位移的实验研究

目的:探讨3种附着体类型作为下颌单侧游离端义齿固位体对基牙的影响。方法:选用Snap附着体、Ceka附着体和Mini-SG附着体,制作单侧附着体义齿,在义齿侧上下牙列间放置食物片,咬合时用LB-72型高精度半导体激光位移测量仪,测量并计算出基牙在不同方向的位移量,并用随机方差分析法进行统计学分析。结果:3种附着体义齿基牙的近远中向、颊舌向、垂直向的位移、倾斜、扭转均有统计学差异(P<0.05)。Mini-SG附着体导致基牙近远中向的倾斜角度最大,Ceka附着体对基牙近远中向和根尖位移的影响最大,Snap附着体基牙的牙合方移动和逆时针旋转角度最小。结论:Snap附着体的弹性固位装置使应力在基牙和剩余牙槽嵴之间得到了最为均匀的分布,Ceka附着体的应力主要由基牙承担,Mini-SG附着体不能有效减少施于基牙上的有害的扭力。