The universal algorithm of maturation for secretory and excretory protein precursors.

During maturation, most proteins undergo different posttranslational modifications. In most simple cases, signal peptidases remove the signal or leader peptide from the precursors of the secretory proteins during their translocation across the ER membrane. For biologically active proteins, such as enzymes, regulatory and defense proteins, toxins, etc., additional maturation-regulating mechanisms were shown to proceed with limited proteolysis of inactive precursors by specific enzymes. A number of specific enzymes from different cell types selectively cleave proproteins at specific processing sites. In this work, we analyzed the sequences of protein precursors synthesized in the excretory glands of different animals and identified new, non-traditional processing sites. They differ from the motifs previously identified in secreted proteins' precursors and enabled us to reconstruct the sequence of events leading to the conversion of protein precursors into the final products (mature proteins). We also found that in animals, the maturation mechanism of secretory and excretory proteins and the set of enzymes involved are species specific. The processing sites identified in protein precursors in this study are useful for a more detailed genome analysis and more accurate mature protein sequence prediction.     

126例心房颤动合并长R-R间期患者的动态心电图分析

Objective To analyze the relationship between atrial fibrillation complicating long R-R interval, escape beat and escape heart rhythm and pathological atrioventricular block by dynamic electrocardiography (DCG). Methods 126 patients with atrial fibrillation were divided into group A (being related to sleep) and group B (being not related to sleep) according to the factor whether long R-R interval, escape beat and escape heart rhythm relevant to sleep. All were detected by DCG for 24 hours. Results The cases with1.5～2.0 s long R-R interval, more than 2.0s long R-R interval, escape beat and escape heart rhythm were (26.02±6.03), (7.39±1.05 ) and (6.90±1.28)in group A and (203.05±41.01), (35.48±7.52), (28.10±6.25) in group B respectively. The cases of group B were markedly more than those in group A. Conclusion Those atrial fibrillation complicating long R-R interval, escape bbeat and escape heart rhythm were related to sleep could not be deemed as pathological atrioventricular block, while those were not related to sleep could be considered pathological atrioventricular block.     

睡眠状态下人体生理信号模糊分析系统的研究

采用LabVIEW技术完成对心电、呼吸、无创血氧和无创血压信号的采集与处理,而后通过MATLAB模糊测量系统对采集的人体生理信号进行模糊预测分析。通过实验检验了人体生理信号检测、处理和模糊预测分析方法的可靠性。LabVIEW技术对人体生理信号的模糊预测分析是有效的,可用于检测阻塞性睡眠呼吸暂停患者的生理状态信号。     

熵指数对异氟烷麻醉中切皮体动反应的预测作用

目的 研究熵指数(包括反应熵和状态熵)对异氟烷复合麻醉中切皮体动反应的预测作用并与双频谱指数(BIS)比较.方法 ASA Ⅱ级择期腹部手术患者20例,按切皮有无体动反应分为体动组(9例)和非体动组(11例).入室后常规监测,然后静注异丙酚、琥珀胆碱、芬太尼快诱导气管插管,持续吸入异氟烷,维持呼气末异氟烷浓度为1.3MAC,维持10min后开始手术,切皮前不用神经肌肉阻滞剂,如果发生体动,则按10%提高下一个患者异氟烷呼气末浓度,如果不动则按10%降低下一个患者异氟烷呼气末浓度.分别于入室、切皮前60s、30s、切皮后45s、120s对每例患者同时行熵指数和BIS监测.结果 两组患者的熵指数值有显著性差异(P＜0.05),而BIS无显著性差异(P＞0.05).反应熵和状态熵可以预测切皮体动,其预测概率(Pk)值分别为0.893 7和0.885 2,BIS不能预测切皮体动,Pk值是0.591 9,熵指数和BIS的Pk值之间有显著性差异(P＜0.05),Pk与反应熵和状态熵的Logistic回归方程分别为ln [Pk/(1-Pk)]=32.517-0.481x和ln [Pk/(1-Pk)]=28.728-0.438x.结论 熵指数监测可以预测异氟烷麻醉中的切皮体动反应,值得临床推广应用.     

三种内固定治疗上肢长骨干骨折的临床比较研究

目的观察天鹅记忆接骨器(swan-likememoryconnector,SMC)治疗上肢长骨干骨折的疗效,并与加压接骨板(dynamiccompressiveplate,DCP)和带锁髓内针(lockedintramedullarynail,LIN)进行临床对比研究。方法随机选择1997年8月～2001年8月入院的新鲜上肢长骨干骨折148例,分别采用SMC(49例)与DCP(50例)、LIN(49例)进行内固定治疗,术后常规抗炎治疗1周,定期拍片并随访患肢功能恢复情况。结果SMC组的手术时间明显低于LIN组与DCP组(P<0.05),三组伤口感染率无差异。SMC组骨愈合时间和骨不连发生率显著短于DCP组和LIN组(P<0.05),而术后功能优良率高于DCP组和LIN组。在SMC固定下,骨折愈合直接由解剖型或类解剖型的骨样骨板状直接替代连接,固定段无应力遮挡和骨质疏松。结论SMC是治疗上肢长骨干骨折的有效方法,优于DCP和LIN。SMC的几何构形和力学特性有利于骨折愈合。在本器固定下,可能存在一种新的尚未被认知的骨折愈合方式。     

Fracture frequency of all-ceramic crowns during dynamic loading in a chewing simulator using different loading and luting protocols

OBJECTIVE: The purpose of this laboratory study was to compare the frequency of failures (complete fractures or partial cracks) of molar crowns made of two different all-ceramic materials during dynamic loading in a chewing simulator, as well as the fracture load when subjected to static loading, in relation to different dynamic loading and luting protocols. METHODS: One hundred and forty-four molar crowns fabricated with IPS Empress or an experimental e.max Press material with high translucency (e.max Press Exp) were luted on CAD/CAM milled PMMA abutments (first lower molar, circular chamfer) either with Variolink or glass-ionomer cement (GIC). All crowns were loaded according to three different loading protocols (n=12 per group) and two force profiles (sinusoidal, rectangular) in a pneumatically driven chewing simulator with a steel stylus (? 8mm) and they underwent simultaneous thermocycling (5 degrees C/55 degrees C). After each phase the crowns were evaluated with regard to fractures or cracks. After dynamic testing, the crowns that did not fail were subjected to compression loading until complete fracture in a universal testing machine (UTM). As control groups, unloaded crowns were also subjected to a UTM. Survival statistics with log-rank tests were applied for the results of the dynamic loading, while ANOVA with post hoc Tukey B was used for the fracture load results and two-way ANOVA was carried out for logarithmically transformed data. Weibull statistics were calculated for pooled fracture load data of the dynamically loaded and control groups. RESULTS: In the 144 IPS Empress crowns, complete fractures were observed in 9 crowns and partial cracks in another 3 crowns. When the data was pooled, a statistically significant increase in fractures occurred when the sinusoidal force profile was applied compared to a rectangular force profile (log-rank, p<0.05). No fractures occurred in the e.max Press Exp crowns. The two-way ANOVA showed that the type of luting protocol used had the most significant effect on the fracture load of both materials. In conjunction with Empress, however, the luting material influenced the variability twice as much as in e.max Press Exp. There was no statistically significant difference in the fracture load of GIC-luted e.max Press Exp crowns and that of the Variolink luted Empress crowns. The force profile had a significant effect on the fracture load only of the Empress crowns but not of the e.max Press Exp crowns. Weibull statistics revealed a higher scattering of the data of dynamically loaded crowns compared to that of the control groups. CONCLUSIONS: For testing all-ceramic materials, dynamic loading is indispensable to draw valid conclusions on clinical performance of all-ceramic molar crowns. A sinusoidal profile is advisable, while a gradual increase of the force amplitude does not significantly affect the results.     

An optimal dynamic output feedback controller for a flexible spacecraft

The design of a low-order dynamic output feedback controller for a flexible spacecraft is carried out using modified linear quadratic Gaussian (LQG) theory. The necessary conditions for optimization are given. The linear equations governing a flexible spacecraft with a central rigid body and two sun-tracking solar panels are presented. The parameters of the Solar Electric Propulsion Spacecraft (SEPS) are selected for analysis and simulation. The optimal gains for the dynamic controller are estimated using an iterative algorithm. The sequential procedure which assures convergence is selected. The initial gains which stabilize the system are chosen on the basis of the principle of a PD controller. A third-order controller for pitch, roll and yaw axes of the 18th-order system, which includes sensor and actuator dynamics, is designed. Numerical simulations carried out to ascertain the performance of the controller show the performance to be satisfactory.     

Rh phenotype prediction by DNA typing and its application to practice

The complexity of the RHD and RHCE genes, which is the greatest of all blood group systems, confounds analysis at the molecular level. RH DNA typing was introduced in 1993 and has been applied to prenatal testing. PCR-SSP analysis covering multiple polymorphisms was recently introduced for the screening and initial characterization of partial D. Our objective is to summarize the accrued knowledge relevant to the approaches to Rh phenotype prediction by DNA typing, their possible applications beyond research laboratories and their limitations. The procedures, results and problems encountered are highly detailed. It is recommended that DNA typing comprises an analysis of more than one polymorphism. We discuss future directions and propose a piecemeal approach to improve reliability and cost-efficiency of blood group genotyping that may eventually replace the prevalent serology-based techniques even for many routine tasks. Transfusion medicine is in the unique position of being able to utilize the most extensive phenotype databases available to check and develop genotyping strategies.     

Reconstruction of plantar defects

Plantar defects are a challenge for the plastic surgeon; from 1984–1995 59 operations were performed in 57 patients. The radial forearm flap and the latissimus dorsi (LD) flaps were mainly used depending on the amount of tissue loss. Local flaps such as dorsalis pedis and instep flaps were used for smaller defects. The radial forearm flap is ideal in terms of thickness and stability for the sole but limited in its size. The LD flap is a safe procedure especially for severe injuries and osteitis, but has the disadvantage of being bulky and debulking procedures are frequently performed. For nerve reconstruction deep sensibility seems to be sufficient in order to obtain stable postoperative results. In this report the different operative methods are evaluated. Since 1991, the patients were monitored with static and dynamic foot pressure measurements and gait analysis to assess the postoperative result and prevent pressure ulcers, scar irritation and hyperkeratosis. Preoperative investigations may contribute to an optimal schedule for planning and stabilization of the operative regimen.     

应用因特网对SARS病毒M蛋白B细胞抗原表位的预测

目的：预测SARS冠状病毒M蛋白的B细胞表位。方法：采用EMBOSS软件结合Hopp＆woods亲水性参数、Janin可及性参数、极性参数、柔韧性参数及二级结构方案对SARS冠状病毒M蛋白的B细胞表位进行了预测，并用吴玉章等已建立的B细胞表位预测方法进行评述。结果：SARS冠状病毒M蛋白B细胞识别的表位可能位于第3～13和153～166位氮基酸等区域内或附近，这2个被预测的表位均含有β—转角和无规卷曲结构。结论：该研究对应用合成肽抗原进行SARS早期诊断研究及相关抗体的制备具有重要指导意义。