躯干运动和负重时对足底支撑面侧向横移的姿势控制

目的:本研究假设自主运动命令和姿势控制信号间有冲突,因此设计在附加重物和不同自主任务的同时给予足底一个模拟受滑的干扰(横移)来观察姿势变化并分析其是否受冲突命令或者力学参数的影响.方法:受试者在执行各种不同的自主任务时,随机给予足底支撑面一个左侧或右侧的横移干扰.这些不同的自主任务包括不负重静止站立、静止站立单手负重5kg、负重5kg站立并躯干静止侧屈15°、负重5kg动态地提重物和放重物5项任务.测量和分析下列参数:中心压力的侧位移(COP)、躯干和股部在冠状面上的角位移和腹内压(IAP).结果:干扰离开质量(向右)、始反应超射的幅度、达到终平衡的时间和达到平衡前COP位移的次数都增加,这种情况可以看作是为了再获得平衡的姿势反应效率降低,因此,如果质量的重力效果能对抗干扰,则再获得平衡的反应效率甚至可以被增进.结论:提重和负重是危害姿势反应效率的因素,因为提重和负重改变了重力效果,加大了对躯干的干扰.在动态条件下躯干的运动不是被横移干扰增强就是被横移干扰抵消,并没有显著地影响改变最终平衡位置姿势校正的效应.因此附加任务的同时给一个支持面上的横移干扰,姿势控制的效应可以被抵消.这个减低的效应可以引起脊柱周围结构的负荷增加和增加受伤的危险性.但是,在恰当地放置负重的位置时,反而可以增进躯干控制和协助恢复姿势平衡.     

人促红细胞生成素在大肠杆菌中融合高表达：稀有密码子对外源蛋白翻译速率的影响

本实验分别用两种融合表达载体（ｐＧＥＸ－２Ｔ及ｐＤＳ－６Ｈ）在大肠杆菌ＸＬ１－Ｂｌｕｅ中表达人促红细胞生成素（ｈ－ＥＰＯ）。结果发现，虽然ｈ－ＥＰＯ基因中大肠杆菌使用频率为０％或１％的密码子占密码子总量的１４．３％，但实验中却取得了较高的蛋白表达量。ｐＧＥＸ－２Ｔ和ｐＤＳ－６Ｈ中表达的融合蛋白（分子量：４４４００和２３８００）分别占细菌总蛋白的２９．７％和１７．５％。从而提示，一个基因中的密码子使用频率与翻译延长速率之间可能不是一种简单的对应关系。表达载体ｐＧＥＸ－２Ｔ中５＇融合基因长度达１３００ｂｐ，而ｐＤＳ－６Ｈ中仅为３６ｂｐ，而ｐＤＳ－６Ｈ但两者表达水平却无显著差异，因此作为翻译起始限制因素的翻译起始区的ＡＴＧ下游顺序仅需长约３６个核苷酸。     

Evolution and path models in human behavioral genetics

The evolutionary implications of the path-analysis model most often used in human behavior genetics are examined. With directional selection, a model of pure vertical environmental transmission does not respond in a fully adaptive fashion. Unless the coefficients of transmission are exactly 0.50, the population mean will not equilibrate at the selective optimum over time. If there is both genetic and vertical environmental transmission, then the population mean can equilibrate at the selective optimum. In the presence of genetic transmission, vertical environmental transmission increases population fitness and has a strong effect on the rapid movement of the mean toward the selective optimum. This raises the intriguing paradox of why empirical evidence suggests that vertical environmental transmission is usually small when it possesses such important fitness properties.This work was supported in part by Grant DA05131 from the National Institute on Drug Abuse.     

Multicultural Health Care in Practice

This study presents a first assessment of the challenges faced by Dutch health care providers dealing with the increasing cultural diversity in Dutch society. Qualitative interviews with 24 Dutch caregivers and policy-makers point to a number of important difficulties encountered when confronted with the growing diversity of patient populations. The study focuses explicitly on the challenges health care providers perceive in their direct interactions with patients. On the basis of the observations of the 24 respondents five strategies were formulated to improve the delivery of care in a multicultural environment. Their findings were further evaluated by confronting the empirical data with care-ethical notions (attentiveness, responsibility, competence, and responsiveness) and intercultural communication-theory.     

Cross talk in surface electromyograms of human hamstring muscles.

Signals generated from muscles other than the muscle(s) of interest (cross talk) can confound the interpretation of surface electromyograms (EMGs). In this study, the amount of cross talk in surface EMGs of human hamstring muscles was estimated using a protocol in which the quadriceps femoris was electrically stimulated via the femoral nerve. EMGs were recorded from the vastus lateralis and the medial and lateral hamstring muscle groups. The amplitude of the EMG response of the vastus lateralis to electrical stimulation was adjusted to match that of its maximum voluntary effort (MVE) under isometric conditions. Subsequent power density spectrum analysis showed that the median frequencies of the signals generated by electrical stimulation and MVE were not significantly different. In conventional bipolar recordings, cross talk in lateral hamstring EMGs averaged 17.1% MVE and in medial hamstring EMGs 11.3% MVE (average-rectified values). The double differential technique significantly reduced cross talk to 7.6% MVE for the lateral hamstrings, and to 4.2% MVE for the medial hamstrings. The double differential technique appears to be more selective than the bipolar technique when recording EMGs from muscles with highly active neighbors and thus should be used in such situations. Software simulations of the double differential technique also appear to be more selective than the bipolar technique and may be used when the number of amplifiers available is limited.     

3D kinematic analysis of the acromioclavicular joint during arm abduction using vertically open MRI.

Many researchers have evaluated the motions of the shoulder girdle, especially scapular and humeral motion. However, few reports exist that describe motions of the acromioclavicular joint. The purpose of the present study was to analyze the 3D kinematics of the acromioclavicular joint during arm abduction using 3D MR images obtained by a vertically open MRI. Fourteen shoulders of seven volunteers were examined in seven static positions from 0 degrees to the maximum abduction in a seated position. 3D surface models of the clavicle and scapula were created, and the movements of the acromioclavicular joint from 0 degrees to each position were calculated using the volume-based registration technique. From these calculations, the translations were evaluated and the rotational motions were analyzed using the concept of the screw axis. In the anteroposterior direction, the clavicle translated most posteriorly (-1.9 +/- 1.3 mm) at 90 degrees of abduction and most anteriorly (1.6 +/- 2.7 mm) at maximum abduction. In the superoinferior direction, the clavicle translated slightly superiorly (0.9 +/- 1.9 mm). When analyzing relative motion of the scapula with respect to the clavicle, the scapula generally rotated about a specific screw axis passing through the insertions of both the acromioclavicular and the coracoclavicular ligaments on the coracoid process. The average rotation was 34.9 +/- 8.4 degrees.     

肛旁脓肿行Ⅰ期根治性手术疗效的探讨

目的：探讨肛旁脓肿行Ⅰ期根治性手术的疗效。方法：对78例肛旁脓肿患者交叉设计分成两组。分别行Ⅰ期根治性手术（RS）和单纯脓肿切开引流（ID），比较术后疗效。结果：RS组病人术后形成肛瘘的发生率远低于ID组。而并发症却无升高趋势，且明显缩短了伤口愈合时间。结论：Ⅰ期根治性手术治疗肛旁脓肿疗效满意，临床使用价值高，值得推广。     

sFGFR1基因的克隆与在RTS系统中的高效表达

目的：克隆sFGFRl(soluble fibroblast growth factors receptor-1)基因，并在RTS(rapid translation system)系统中高效表达相应蛋白．方法：培养Swiss rat 3T3 fibroblast细胞株，提取总RNA，用RT—PCR方法获取鼠sFGFR1 cDNA片段，酶切后克隆到pIVEX2．3d载体并进行序列分析；采用Roche RTS ProteinMaster500系统，高效表达sFGFR1蛋白并用Western Blot鉴定表达的蛋白．结果：克隆了sFGFR1基因，测序证实序列正确；Western Blot证实sFGFR1蛋白在RTS系统中高效表达．结论：克隆了sFGFR1基因并在RTS系统获得高效表达．     

Posterior instability near extension is related to clinical disability in isolated posterior cruciate ligament deficient patients

The purpose of this study is to evaluate the relationship between the magnitude of knee laxity and posterior instability at different knee flexion angles and clinical disability in isolated posterior cruciate ligament (PCL) deficient patients. Knee laxity at 20° and 70° of knee flexion were evaluated using KT-2000 arthrometer, and the posterior instability at 20°, 45° and 90° of flexion were evaluated using stress radiography. We assessed the differences in the knee laxity and the tibial translation between isolated PCL deficient knees and normal knees, and between the patients with giving-way during activities of daily living (ADL) and without giving-way. There were statistical differences in the knee laxity and the tibial translation at all knee flexion angles between the PCL deficient knees and normal knees. The magnitude of the knee laxity at 20° of flexion measured with KT-2000 arthrometer was significantly larger in the patients with giving-way than those in the patients without giving-way although there was no significant difference in the tibial translation at 70° between the two groups. The tibial translation in both medial and lateral compartments at 20° and 45° measured with stress radiography were significantly larger in the patients with giving-way than those in the patients without giving-way although there was not significant difference at 90° between the two groups. These results suggested that the magnitude of the knee laxity and the posterior tibial translation at shallow knee flexion angles would be related to giving-way during ADL in isolated PCL deficient patients.