离体脊柱生物力学测试的加载方法研究进展

离体脊柱标本三维运动载荷-位移特性的描述是脊柱生物力学研究的基础,如何准确地模拟在体脊柱的载荷与运动情况是脊柱生物力学研究的难点。国内外学者从测试理论与测试工具上都进行了大量的研究。目前脊柱三维运动测试按照控制方法主要分为载荷控制、位移控制和混合控制。基于不同的控制方法,测试工具也在不断的发展与完善之中。总结目前国内外研制的脊柱离体加载装置的工作原理,并分析其主要优缺点,为离体脊柱生物力学加载装置研究提供参考。     

基于6自由度机械臂的脊柱运动控制

目的研究并建立基于6自由度机械臂的脊柱运动控制系统,为模拟脊柱运动及内固定植入物相关生物力学测试提供稳定有效的测试方案。方法首先研究L2～5节段脊柱系统刚度矩阵识别方法,并通过此刚度矩阵对进行系统解耦。其次,联合六轴机械臂控制系统及增步式PID控制算法,建立各个轴向运动的直接力控制系统。最后,通过此套六轴直接力控制系统对L2～5节段脊柱模型进行前屈后伸(flexion-extension,FE)、左右侧弯(lateral bending,LB)、左右扭转(axial rotation,AR)运动模拟,各个运动中均只在主运动轴方向上施加7.5 N·m纯力矩。结果脊柱L2～5节段在FE、LB、AR运动中活动度(range of motion, ROM)分别为23.01°、27.92°、9.81°。主运动轴运动载荷均能达到7.5 N·m,其他非主运动轴均能保持在零载荷,控制误差均方根值(root mean square, RMS)小于3 N和0.1 N·m。结论提出的含系统刚度矩阵解耦和增步式PID的直接力控算法,能够有效地对脊柱施加FE、LB、AR运动上的纯力矩,控制精度较高。研究结果对各类腰颈椎生物力学测试具有较高的工程应用价值。     

颈椎内植入固定器生物力学性能测试系统的研究

在颈椎生物力学研究中,通过离体实验对颈椎内植入固定器的生物力学性能进行评价是国际上普遍采用并认可的方法.本研究利用多靶点三维运动跟踪系统和USB数据采集卡,以LabVIEW和Matlab为软件开发平台,构建了颈椎内植入固定器生物力学性能测试系统.测试参数包括三维运动角度范围(ROM)和压力载荷值.对颈椎模型的测试结果表明,本系统能有效地用于颈椎生物力学的离体实验测试.     

基于关节机器人的人体脊柱生物力学试验装置设计

目的建立机器人生物力学试验装置,进行人体脊柱标本生物力学实验研究。方法利用solidwork软件进行夹具设计,通过VisualC++6.0平台进行以太网套接字Socket编程实现PC机与机器人控制器之间的网络通信,读取机器人末端执行器的位置和旋转角度。PC机里面插入数据采集板读取力(力矩)传感器在三维空间中的力和力矩。位姿与力矩数据作为控制程序的输入数据,通过控制程序的处理,绘制出力-位移的二维曲线图,协助分析得出实验结果。结果开发并建立一套基于机器人的用于生物力学特性研究的实验装置,开发了相应的控制软件(力控制、位移控制、混合力/位移控制)及各类监控程序。结论设计出一套基于计算机控制的6自由度机器人全新实验装置,采用混合力/位移控制方法对实验对象进行加载,可以很好地测试脊柱功能单元各组织结构的功能和受力状态,很容易地确定脊柱退变和各类手术对脊柱功能单元各组织结构所承担负载的影响。     

新型3D打印多孔钛人工椎体在猪脊柱模型置换前后的生物力学测试研究

目的通过对新型3D打印多孔钛人工椎体在猪脊柱模型置换前后的生物力学测试比较研究,评价该新型3D打印人工椎体的活动范围情况和即刻的生物力学稳定性。方法选取18具新鲜相近的猪脊柱标本(L1-L6),根据L3椎体置换前后,分为置换前组和置换后组。分别测试前屈、后伸、左右侧屈、左右旋转的位移角度变化。结果在0~8N.m逐级加载中,置换后组运动节段在前屈、后伸、左右侧屈各向量的位移角度变化明显小于置换前组,差异有统计学意义(0.05),而在轴位旋转位上,两者无显著性差异(0.05)。结论新型3D打印人工椎体的设计具有合理性和创新性,在猪脊柱模型L3椎体置换后,即刻可获得良好的生物力学稳定性。     

脊柱生物力学信号智能分析系统的研究

目的为脊柱生物力学测试平台开发一套信号智能分析系统,对不同采集装置产生的海量数据进行格式规范与整合,实现对数据的科学管理和快速处理。方法利用OptotrakCertus运动测量系统、MTS材料试验机和USB数据采集卡,以Matlab和MySQL为软件开发平台,搭建脊柱生物力学信号智能分析系统。对脊柱模型的生物力学性能进行测试,测试参数主要包括脊柱各节段运动角度、加载力矩。结果由系统自动处理得到的脊柱各节段运动角度变化规律,与力及力矩载荷的变化一致。结论本系统能有效应用于脊柱及其内固定器械的生物力学测试中。     

人工颈椎间盘置换术与融合术的生物力学比较

目的 分析颈前路植骨融合术（anterior cervical discectomy and fusion,ACDF）与颈椎间盘置换术（total disc replacement,TDR）后颈椎生物力学特性。方法 采用12具人体颈椎标本,通过三维非接触式光电测量系统及位移控制方式,测试原始状态（intact）、TDR及ACDF术后各节段在前屈与后伸、左侧弯与右侧弯、左旋转与右旋转6种独立工况的运动和载荷分布,并探讨颈椎正常生理运动规律及植入器械特点。结果TDR术后,颈椎各节段运动保留效果明显,能恢复接近正常的运动,并以屈伸、旋转工况为优;同等工况下ACDF术后手术节段运动丢失达73.41%,其他节段运动也存在明显改变。侧弯工况两者均存在较大运动改变,TDR达45.92%,ACDF达108.06%。试验发现,颈椎正常生理运动为空间三轴耦合运动,以侧弯工况耦合程度最大,绕X轴运动分量达35%,TDR术后,颈椎能恢复接近正常的耦合运动规律。结论TDR术能使颈椎恢复更接近正常的生理运动,在屈伸、旋转工况效果最好,侧弯次之。本研究为TDR与ACDF的临床手术提供理论依据和定量参考。     

基于LabVIEW图像处理技术的脊柱运动范围测量系统研究

针对脊柱生物力学测量的重要意义,在LabVIEW开发环境中构建基于图像处理技术快速获取脊柱运动范围(ROM)的测量系统。运用LabVIEW中的机器视觉模块对采集到的原始脊柱图像进行预处理后提取标记针角度信息,最终获得脊柱的ROM。选取6具T7-T10节段人体脊柱标本,实施左/右侧弯、前屈、后伸、顺/逆时针扭转6个方向上的加载,利用该系统测量在载荷为1~5N·m时T8-T9节段的ROM。实验结果表明,该系统能够精确、快速地测定脊柱的ROM,为脊柱生物力学研究者提供了操作简便可靠性强的测量工具。     

手术矫正脊柱后凸畸形的生物力学分析

目的探讨脊柱截骨矫正后凸畸形的生物力学特点。方法12具新鲜猪胸腰椎段脊柱标本,随机分成截骨组和对照组,每组6具,截骨组标本截骨两处并行椎弓根钉固定,在生理负荷下进行前屈、后伸、左右侧屈和顺逆时针轴向旋转6种运动范围的测试,记录载荷值大小,并行统计学分析。结果生理负荷下截骨组屈伸、侧屈和轴向旋转运动稳定性与对照组无差异性。结论脊柱截骨后采用椎弓根钉固定后的稳定性能够达到对照组水平。     

脊柱三维运动测试实验装置的研制

目的研制一套模拟人体脊柱在体运动的离体加载装置,进行脊柱生物力学实验研究。方法利用轴承原理,在加载盘上设计安装旋转锁定装置,加载时旋转于所需测试位置后用螺栓锁定状态,再通过万能材料试验机提供自动加载动力源,在脊柱标本上施加前屈/后伸、左/右侧弯和左/右轴向旋转6个方向的纯力矩,模拟脊柱的在体运动,并用三维扫描仪对脊柱标本加载前后位置进行扫描测量。利用该加载装置对6具1岁龄猪颈椎(C2-C6)在6种加载状态下进行运动范围测量,并对该加载装置进行精度验证和误差分析。结果建立了一套人体脊柱三维运动实验装置,6具猪颈椎标本经加载测量得到6个方向的中性区和活动范围数据,总测量误差值小于3.5%。结论该装置巧妙的设计较好地模拟了脊柱在体运动,可实现人体脊柱的快速加载,费用低、方法简单实用,能大大提高实验的效率,在脊柱的离体加载方面具有较大的推广应用价值。     

Opportunities and challenges in the prevention and control of cancer and other chronic diseases: children's diet and nutrition and weight and physical activity

OBJECTIVE: The purpose of this article is to review the role of behavioral research in disease prevention and control, with a particular emphasis on lifestyle- and behavior-related cancer and chronic disease risk factors--specifically, relationships among diet and nutrition and weight and physical activity with adult cancer, and tracking developmental origins of these health-promoting and health-compromising behaviors from childhood into adulthood. METHOD: After reviewing the background of the field of cancer prevention and control and establishing plausibility for the role of child health behavior in adult cancer risk, studies selected from the pediatric published literature are reviewed. Articles were retrieved, selected, and summarized to illustrate that results from separate but related fields of study are combinable to yield insights into the prevention and control of cancer and other chronic diseases in adulthood through the conduct of nonintervention and intervention research with children in clinical, public health, and other contexts. RESULTS: As illustrated by the evidence presented in this review, there are numerous reasons (biological, psychological, and social), opportunities (school and community, health care, and family settings), and approaches (nonintervention and intervention) to understand and impact behavior change in children's diet and nutrition and weight and physical activity. CONCLUSIONS: Further development and evaluation of behavioral science intervention protocols conducted with children are necessary to understand the efficacy of these approaches and their public health impact on proximal and distal cancer, cancer-related, and chronic disease outcomes before diffusion. It is clear that more attention should be paid to early life and early developmental phases in cancer prevention.     

Pain and Effusion and Quadriceps Activation and Strength

Context:

Quadriceps dysfunction is a common consequence of knee joint injury and disease, yet its causes remain elusive.

Objective:

To determine the effects of pain on quadriceps strength and activation and to learn if simultaneous pain and knee joint effusion affect the magnitude of quadriceps dysfunction.

Design:

Crossover study.

Setting:

University research laboratory.

Patients or Other Participants:

Fourteen (8 men, 6 women; age = 23.6 ± 4.8 years, height = 170.3 ± 9.16 cm, mass = 72.9 ± 11.84 kg) healthy volunteers.

Intervention(s):

All participants were tested under 4 randomized conditions: normal knee, effused knee, painful knee, and effused and painful knee.

Main Outcome Measure(s):

Quadriceps strength (Nm/kg) and activation (central activation ratio) were assessed after each condition was induced.

Results:

Quadriceps strength and activation were highest under the normal knee condition and differed from the 3 experimental knee conditions (P < .05). No differences were noted among the 3 experimental knee conditions for either variable (P > .05).

Conclusions:

Both pain and effusion led to quadriceps dysfunction, but the interaction of the 2 stimuli did not increase the magnitude of the strength or activation deficits. Therefore, pain and effusion can be considered equally potent in eliciting quadriceps inhibition. Given that pain and effusion accompany numerous knee conditions, the prevalence of quadriceps dysfunction is likely high.Key Words: arthrogenic muscle inhibition, central activation failure, voluntary activation, muscles

Key Points

• Knee pain and effusion resulted in arthrogenic muscle inhibition and weakness of the quadriceps.
• The simultaneous presence of pain and effusion did not increase the magnitude of quadriceps dysfunction.
• To reduce arthrogenic muscle inhibition and improve muscle strength, clinicians should employ interventions that target removing both pain and effusion.

Quadriceps weakness is a common consequence of traumatic knee joint injury^1,2 and chronic degenerative knee joint conditions.^3,4 Arthrogenic muscle inhibition (AMI), a neurologic decline in muscle activation, results in quadriceps weakness and hinders rehabilitation by preventing gains in strength.⁵ The inability to reverse AMI and restore muscle function can lead to decreased physical abilities,⁶ biomechanical deficits,⁷ and possibly reinjury.⁵ Furthermore, researchers^8,9 have suggested that quadriceps weakness resulting from AMI may place patients at risk for developing osteoarthritis in the knee. In light of the substantial influence of quadriceps AMI on these clinically relevant outcomes, we need to improve our understanding of the factors that contribute to this neurologic decline in muscle activity so efforts to target and reverse it can be implemented and gains in strength can be achieved more easily.Joint injury and disease are accompanied by numerous sequelae (ie, pain, swelling, tissue damage, inflammation), so ascertaining which one ultimately leads to neurologic muscle dysfunction is difficult. Whereas a joint effusion can result in AMI,^10–12 the effects of pain are less understood despite many clinicians attributing AMI to pain. Using techniques that introduce knee pain without accompanying injury may provide insights into the role of pain in eliciting AMI.The degree of knee joint damage may play a role in the quantity of AMI that manifests. Hurley et al^13,14 demonstrated that quadriceps AMI, measured using an interpolated-twitch technique, was greater in patients with extensive traumatic knee injury (eg, fractured tibial plateau, ruptured medial collateral ligament, and medial meniscectomy) than patients with isolated joint trauma (ie, isolated anterior cruciate ligament [ACL] rupture). Similarly, patients with more knee joint symptoms (ie, greater number of symptoms and increased severity of symptoms) may present with greater magnitudes of quadriceps inhibition. Recently, investigators¹⁵ have suggested that patients with more pain display less quadriceps strength, supporting this tenet. Given that effusion and pain often present simultaneously with joint injuries and diseases, such as ACL injury and osteoarthritis, examining both the isolated and cumulative effects of these sequelae appears warranted to determine if they influence the magnitude of muscle inhibition.Experimental joint-effusion and pain models are safe and effective experimental methods that allow for the isolated examination of their effects on muscle function. The effusion model, whereby sterile saline is injected directly into the knee joint capsule,⁷ produces a clinically relevant magnitude of the joint effusion that may be present with traumatic injury. Effusion is thought to activate group II afferents responding to stretch or pressure,^16–18 which in turn may facilitate group Ib interneurons and result in quadriceps AMI.⁵ The pain model involves injecting hypertonic saline into the infrapatellar fat pad to produce anteromedial knee pain similar to that described in patients with patellofemoral pain syndrome.¹⁹ Pain is considered to initiate AMI through activation of group III and IV afferents that act as nocioceptors to signal damage or potential damage to joint structures.^16–18 The firing of these afferents then may lead to facilitation of group Ib interneurons, the flexion reflex, or the gamma loop, ultimately resulting in quadriceps inhibition.²⁰ Thus, these models allow us to create symptoms that are associated with knee injury and have the added benefit of providing a way to examine their effects in isolation.Therefore, the purpose of our study was to determine the effects of pain on quadriceps strength and activation and to learn if simultaneous pain and knee joint effusion would affect the magnitude of quadriceps dysfunction. We hypothesized that pain alone would result in quadriceps inhibition and that the magnitude of inhibition would be greater when effusion and pain were present simultaneously.     

Postinfectious immunodeficiency and autoimmunity: pathogenic and clinical values and implications

Autoimmunity is still a mystery of clinical immunology and medicine as a whole. The etiology and pathogenesis of autoimmune disorders remain unclear and, thus, are assessed as a balance between hereditary predisposition, triggering factors and the appearance of autoantibodies and/or self-reactive T cells. Among the immunological armamentarium, molecular mimicry, based on self-reactive T- and B-cell activation by cross-reactive epitopes of infectious agents, is of special value. Hypotheses regarding the possible involvement of molecular mimicry in the development of postinfectious autoimmunity are currently very intriguing. They provide new approaches for identifying etiological agents that are associated with postinfectious autoimmunity, paired microbial- and tissue-linked epitopes targeted for autoimmune reaction determination, postinfectious autoimmunity pathogenesis recognition and specific prevention, and therapy for autoimmune disorder development.     

Beta-endorphin and drug-induced reward and reinforcement

Although drugs of abuse have different acute mechanisms of action, their brain pathways of reward exhibit common functional effects upon both acute and chronic administration. Long known for its analgesic effect, the opioid beta-endorphin is now shown to induce euphoria, and to have rewarding and reinforcing properties. In this review, we will summarize the present neurobiological and behavioral evidences that support involvement of beta-endorphin in drug-induced reward and reinforcement. Currently, evidence supports a prominent role for beta-endorphin in the reward pathways of cocaine and alcohol. The existing information indicating the importance of beta-endorphin neurotransmission in mediating the reward pathways of nicotine and THC, is thus far circumstantial. The studies described herein employed diverse techniques, such as biochemical measurements of beta-endorphin in various brain sites and plasma, and behavioral measurements, conducted following elimination (via administration of anti-beta-endorphin antibodies or using mutant mice) or augmentation (by intracerebral administration) of beta-endorphin. We suggest that the reward pathways for different addictive drugs converge to a common pathway in which beta-endorphin is a modulating element. beta-Endorphin is involved also with distress. However, reviewing the data collected so far implies a discrete role, beyond that of a stress response, for beta-endorphin in mediating the substance of abuse reward pathway. This may occur via interacting with the mesolimbic dopaminergic system and also by its interesting effects on learning and memory. The functional meaning of beta-endorphin in the process of drug-seeking behavior is discussed.     

PTEN与信号转导及肿瘤

ＴＥＮ[1] (ｐｈｏｓｐｈａｔａｓｅａｎｄｔｅｎｓｉｎｈｏｍｏｌｏｇｙｄｅｌｅｔｅｄｏｎｃｈｒｏｍｏｓｏｍｅｔｅｎ)又名ＭＭＡＣ1 [2 ] (ｍｕｔａｔｅｄｉｎｍｕｔｉｐｌｙａｄａｎｃｅｄｃａｎｃｅｒ 1 )和ＴＥＰ1 [3 ] (ＴＧＦ -βｒｅｇｕｌａｔｅｄａｎｄｅｐｉｔｈｅｌｉａｌｃｅｌｌ -ｒｉｃｈｅｄｐｈｏｓｐｈａｔａｓｅ 1 ) (以下均称为ＰＴＥＮ) ,是 1 997年由 3个研究小组先后发现的一个具有双特异磷酸酶活性的抑癌基因。ＰＴＥＮ基因异常广泛存在于人类多种恶性肿瘤 ,如恶性神经胶质瘤、前列腺癌、子宫内膜癌、黑色素瘤等…     

Tobacco and alcohol and the risk of head and neck cancer

Summary We carried out two case-control studies on the relative risk of head and neck cancer in association with tobacco and alcohol consumption. The first study carried out at the ENT Department of the University hospitals of Heidelberg and Giessen (FRG) comprised 200 male patients with squamous cell cancer of the head and neck and 800 control subjects matched for sex, age, and residential area (1:4 matching design). Of the tumour patients, 4.5% had never smoked, in contrast to 29.5% of the control group. The average tobacco and alcohol consumption of the patients was approximately twice as high as in the control subjects. The highest alcohol and tobacco consumption was observed in patients suffering from oropharyngeal cancer. Tobacco and alcohol increased the risk of head and neck cancer in a dose-dependent fashion and acted as independent risk factors. In heavy smokers (> 60 pack-years) a relative risk of 23.4 (alcohol adjusted) was calculated. Combined alcohol and tobacco consumption showed a synergistic effect. The risk ratio increased more in a multiplicative than in an additive manner. Oral and laryngeal cancer were associated with the highest tobacco-associated risk values. The highest ethanol-associated risk values were associated with oropharyngeal and laryngeal cancer. The second study was carried out at the ENT Department of the University of Heidelberg on 164 males with squamous cell carcinoma of the larynx and 656 control subjects matched for sex, age and residential area (1:4 matching design). Of the cases, 4.2% had never smoked, compared with 28.5% of the control subjects. The risk of laryngeal cancer by tobacco consumption was dose dependent, reaching a maximum value of 9.1 (adjusted for alcohol) for a consumption of more than 50 tobacco-years (TY). The relative risk of laryngeal cancer associated with alcohol intake was also dose dependent, reaching a value of 9.0 (adjusted for tobacco) for a mean daily consumption of more than 75 g alcohol. An analysis of subsite specific risks showed that heavy smokers (> 50 TY) carried a nearly ten times higher risk of supraglottic cancer than of glottic cancer. The risk of supraglottic cancer from alcohol consumption was also higher than that of glottic cancer.     

Muscle strength and serum testosterone,cortisol and SHBG concentrations in middle-aged and elderly men and women

Forty healthy males (M) and females (F) divided into two different age groups i.e. M50 years (range 44–57; n= 9), F50 years (range 43–54; n= 9), M70 years (range 64–73; n= 11) and F70 years (range 63–73; n= 11) volunteered as subjects for examination of muscle cross-sectional area (CSA) and maximal voluntary isometric force production characteristics of the leg extensor muscles and serum androgen and sex hormone binding globulin (SHBG) concentrations. The CSA in the male groups was greatly larger (P < 0.01) than in the female groups and both elderly groups demonstrated slightly (n.s.) smaller values in the CSA than the two middle-aged groups. Maximal force of 2854 ± 452 N in M50 was greater (P < 0.05) than that of 2627 ± 752 N recorded for F50 as well as the force of 2787 ± 843 in M70 was greater (P < 0.001) than that of 1849 ± 295 recorded for F70. The force between F50 and F70 differed significantly (P < 0.05) from each other. The maximal rate of force production in M50 was greater (P < 0.01) than in F50 as well as in M70 greater (P < 0.001) than in F70. Both middle-aged groups demonstrated greater (P < 0.05) values than the respective elderly groups of the same sex. The individual values in the CSA correlated with the values in maximal force both in the middle-aged subjects (r= 0.66; P < 0.01) and in the elderly subjects (r= 0.69; P < 0.01). The mean concentration of serum testosterone in M50 was slightly (n.s.) greater than in M70 and in F50 significantly (P < 0.05) greater than in F70. Serum SHBG levels were lower in the males (P < 0.01) than in the females and serum testosterone/SHBG ratio in M70 and in F70 were lower (P < 0.05) than in M50 and in F50, respectively. In the females significant positive correlations were observed between the individual values in serum testosterone concentration and the values both in the CSA (r= 0.46; P < 0.05) and in maximal force (r= 0.62; P < 0.01) as well as between serum testosterone/SHBG ratio and both the CSA (r= 0.55; P < 0.05) and maximal force (r= 0.68; P < 0.01). The present results imply that the decreasing basal level of blood testosterone over the years in aging people, especially in females, may lead to decreasing anabolic effects on muscles thus having an association with age-related declines in the maximal voluntary neuromuscular performance capacity in aging people.     

海洛因成瘾与学习记忆

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