平板运动试验阴性患者最大ST/HR斜率对冠心病的诊断价值

目的探讨平板运动试验阴性患者最大ST/HR斜率对冠心病的诊断价值.方法选择122例平板运动试验阴性而临床有明显冠心病指征的患者进行冠状动脉造影,测定其最大ST/HR斜率.结果平板运动试验阴性患者最大ST/HR斜率诊断冠心病的敏感性为68.2%,特异性为80.8%,准确性为76.2%;运动峰值心率＜预计最大心率之85%组最大ST/HR斜率诊断冠心病的敏感性为92.8%,特异性为86.7%,准确性为89.7%,高于运动峰值心率≥预计最大心率之85%组.结论平板运动试验阴性患者最大ST/HR斜率对冠心病的临床诊断有较高的敏感性、特异性和准确性,尤其是对低运动水平的患者,对减少运动试验诊断的漏诊率具有重要意义.     

气功对冠心病人CM_5ST段/心率斜率的影响

37名冠心病患者随机分为气功治疗组(22人)和对照组(15人)。气功治疗组接受12周动功治疗,对照组接受安慰剂治疗,治疗前后均测定CM_5 ST段/心率斜率。结果发现动功治疗组CM_5 ST段/心率斜率减少,而对照组不变或增大,两组有显著性差异,ST段下移及常规分级运动试验其它指标在两组间无显著差异。表明CM_5ST段/心率斜率是一个敏感的心肌缺血指标。     

Study of the course of the incidence angle during growth

Standing posture is made possible by hip extension and lumbar lordosis. Lumbar lordosis is correlated with pelvic parameters, such as the declivity angle of the upper surface of the sacrum and the incidence angle, which determine the sagittal morphotype. Incidence angle, which is different for each individual, is known to be very important for upright posture, but its course during life has not yet been established. Incidence angle was measured on radiographs of 30 fetuses, 30 children and 30 adults, and results were analysed using the correlation coefficientr and Student's t test. A statistically significant correlation between age and incidence angle was observed. Incidence angle considerably increases during the first months, continues to increase during early years, and stabilizes around the age of 10 years. Incidence is a mark of bipedism, and its role in sagittal balance is essential.     

Effects of Posterior Tibial Slope on a Posterior Cruciate Retaining Total Knee Arthroplasty Kinematics and Kinetics

BackgroundIt has been hypothesized that increasing posterior tibial slope can influence condylar rollback and play a role in increasing knee flexion. However, the effects of tibial slope on knee kinematics are not well studied. The objective of this study is to assess the effects of tibial slope on femorotibial kinematics and kinetics for a posterior cruciate retaining total knee arthroplasty design.MethodsA validated forward solution model of the knee was implemented to predict the femorotibial biomechanics of a posterior cruciate retaining total knee arthroplasty with varied posterior slopes of 0°-8° at 2° intervals. All analyses were conducted on a weight-bearing deep knee bend activity.ResultsIncreasing the tibial slope shifted the femoral component posteriorly at full extension but decreased the overall femoral rollback throughout flexion. With no tibial slope, the lateral condyle contacted the polyethylene 6 mm posterior of the midline, but as the slope increased to 8°, the femur shifted an extra 5 mm, to 11 mm posterior of the tibial midline. Similar shifts were observed for the medial condyle, ranging from 7 mm posterior to 13 mm posterior, respectively. Increasing posterior slope decreased the posterior cruciate ligament tension and femorotibial contact force.ConclusionThe results of this study revealed that, although increasing the tibial slope shifted the femur posteriorly at full extension and maximum flexion, it reduced the amount of femoral rollback. Despite the lack of rollback, a more posterior location of condyles suggests lower chances of bearing impingement of the posterior femur and may explain why increasing slope may lead to higher knee flexion.     

基坑边坡变形和稳定性的离心试验研究

通过土工离心模型试验对上海某放坡式开挖基坑边坡的变形特性和稳定性进行了研究,揭示了基坑边坡变形的时间效应及其对边坡稳定性的影响。试验结果表明能长期稳定的边坡其边坡变形速率呈现出加速、接近匀速和衰减等3个明显的阶段;能瞬时稳定但不能长期稳定的边坡,其失稳发生在边坡位移速率增大的阶段。     

UV法及Weibull模型评价复方法莫替丁分散片的溶出特性

目的 :评价复方法莫替丁分散片在不同测定方法下的溶出特性。方法 :采用转篮法及桨法测定复方法莫替丁分散片的体外溶出度 ,溶液吸收度以紫外分光光度法测定 ;实验数据采用Excel软件 ,以Weibull分布模型求算溶出参数并拟合回归直线 ,用t检验进行统计学分析。结果 :采用转篮法及桨法测定本复方法莫替丁分散片的溶出度 ,其td 值分别为 1 30 6 3及 0 7931min ;直线斜率间存在统计学差异 (P <0 0 1)。结论 :本品溶出过程受测定方法影响较大 ,提示本品的体内溶出过程与胃肠运动密切相关。     

从滑坡现象和风险社会理论看安乐死

“安乐死”问题一直是一个极具争论的议题，赞成者和反对者各持一方，近年来，国内赞成安乐死的呼声越来越高，笔者从风险社会理论角度出发，对比分析荷兰安乐死立法的社会背景和实践中的滑坡现象。认为像我们这样有着深厚传统文化，卫生资源相对贫乏，医疗保障水平低，法制还不十分健全的国家，在目前社会条件下，对安乐死的问题应审慎。     

Analysis of parametric histogram from dynamic contrast‐enhanced MRI: application in evaluating brain tumor response to radiotherapy

Dynamic contrast‐enhanced MRI (DCE MRI) has been used to study tumor response to treatment for many years. In this study, the modified full width at half‐maximum (mFWHM), calculated from the wash‐in slope histogram, is proposed as a parameter for the evaluation of changes in tumor heterogeneity which respond to radiotherapy. Twenty‐five patients with brain tumors were evaluated and divided into the nonresponder group (n = 11) and the responder group (n = 14) according to the Response Evaluation Criteria in Solid Tumors (RECIST). All selected tumors were evaluated by mFWHM ratios of post‐ to pre‐therapy (the ratio was defined as the therapeutic mFWHM ratio, TMR). The changes in kurtosis of the histograms and the averaged K^trans within a tumor were also calculated for comparison. The receiver operating characteristic analysis and Kaplan–Meier curves were used to examine the diagnosis ability. The TMR values were significantly higher in nonresponders than in responders (p < 0.001). When compared with the other two parameters, the proposed method also demonstrated better sensitivity and specificity. When adopting the TMR for the estimation of prognosis after therapy, there was a significant difference between the population survival curves. In conclusion, the derived mFWHM reflects tumor heterogeneity, and the ability to depict patient survival probability from TMR corresponds well with that from RECIST. The results reveal that, in brain tumors, progression may be exhibited not only by tumor size, but also by tumor heterogeneity. Copyright © 2012 John Wiley & Sons, Ltd.     

Influence of cartilage and menisci on the sagittal slope of the tibial plateaus

We analyzed the magnetic resonance studies of the knee in 80 subjects, 45 men and 35 women with a mean age of 38.9 years, who showed no pathological condition of the joint. Using an imaging visualization software, the sagittal longitudinal axis of the tibia was identified. The angle between this axis and a line tangent to the bone profile of the tibial plateau (bone slope) and to the superior border of the menisci (meniscal slope) were calculated. Thickness of anterior and posterior portion of menisci and underlying cartilage were also measured. The bone slope averaged 8° and 7.7° on the medial and lateral sides, respectively. The mean meniscal slope was 4.1° and 3.3° on the medial and lateral sides, respectively, with a significant difference compared with the bone slope. Menisci and underlying cartilage were significantly thicker in their posterior than their anterior portion (7.6 and 5.2 mm, respectively, in the medial compartment; 8.6 and 5.2 mm, respectively, in the lateral compartment). The presence of cartilage and menisci implies a significant decrease in the posterior tibial slope. In the lateral compartment, the greater the bone slope, the larger the difference between bone and meniscal slope, which means that a marked posterior tilt of the lateral tibial plateau is decreased by the cartilage and meniscus. These findings should be taken into account in planning surgical procedures which affect the slope of the articular tibial surface. Clin. Anat. 26:883–892, 2013. © 2012 Wiley Periodicals, Inc.