The “graft versus leukemia” effect under conditions of mixed chimeric hemopoiesis

The “graft versus leukemia” effect can be induced in (C57B1/6×DBA) F₁ mice by two transplantations of cell suspensions containing bone marrow cells and splenocytes of (CBA×C57B1/6) F₁ mice and an injection of cyclophosphamide. The recipients of cell allotransplants were characterized by mixed chimeric hemopoiesis. These data outline a new approach to induction of the graft versus leukemia effect, requiring no complete elimination of the recipient's hemopoiesis and characterized by a low probability of lethal graft-versus-host reaction. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 123, No. 5, pp. 562–565, May, 1997     

间断头高位与站立位可对抗模拟失重大鼠股动脉收缩反应性的降低

目的 观察和比较头高位（HUT）与站立位（STD）对模拟失重所致股动脉收缩反应性降低的影响及其时间依赖性。方法 49只雄笥SD大鼠随机分为对照组、模拟失重组、头高位2h组、头高位4h组、站立位1h组、站立位2h组和站立位4h组，每组7只。利用离体股动脉血管环技术测定7组大鼠股动脉对血管收缩剂的反应。结果 悬吊大鼠股动脉血管环对KCl和苯肾上腺素的收缩反应性显降低，头高位与站立位组大鼠的股动脉血管环对KCl和苯肾上腺素收缩反应均较悬吊组显增强，与同步对照组相比已无显差异。结论 4wk模拟失重可以使大鼠股动脉的收缩反应性降低，而头高位与站立位均可对抗大鼠股动脉的收缩反应性的降低，这些结果提示间断性人工重力可对抗失重对血管所产生的影响。     

动脉波形分析计算心排出量及临床应用

动脉波形分析技术用于测量心排出量(arterial pressure-based cardiac output,APCO)和每搏输出量变异指数(stroke volume variation,SVV)是一项新的微创血流动力学技术,它能够连续通过对外周动脉的波形特征结合患者的基本信息(年龄、性别、身高、体重等)进行分析测定心排出量(CO),并且不需要通过其他方法来校准.临床上已经显示出可以接受的准确性和良好的即时性和方便性,但也存在一定的局限性,如在一些心脏疾病如主动脉返流、二尖瓣返流或给予α1受体激动药,APCO并不能准确反映心排血量.     

体外冲击波对兔输尿管形态及组织学影响的研究

目的 :探讨冲击波 (SW )对输尿管形态的影响。方法 :将 4 2只成年兔随机分为 7组 ,每组 6只。第 1组为正常对照组 ;第 2～ 6组为液电式SW组 ;第 7组为电磁式SW组。各组接受冲击并在冲击后不同时间取材。全部标本行常规病理检查并予评分。结果 :第 2～ 5组和第 7组 ,肉眼可见焦点周围组织有出血、水肿等改变 ,输尿管直径较冲击前显著增加 (P <0 .0 1 )。光镜下可见平滑肌细胞变性及管腔狭窄 ,病理量化评分显著高于正常组 (P <0 .0 5 ) ;电镜下则有肌细胞线粒体破坏等改变。第 6组形态改变不明显 ,病理评分和正常组的区别无显著性意义。结论 :临床剂量的冲击波能导致输尿管多种病理变化。冲击后第 5天 ,输尿管形态已基本恢复正常。由液电式和电磁式冲击波所致的输尿管急性损伤程度无明显的区别     

Adaptation in a rotating artificial gravity environment

The centripetal force generated by a rotating space vehicle is a potential source of artificial gravity. Minimizing the cost of such a vehicle dictates using the smallest radius and highest rotation rate possible, but head movements made at high rotation rates generate disorienting, nauseogenic cross-coupled semicircular canal stimulation. Early studies suggested 3 or 4 rpm as the highest rate at which humans could adapt to this vestibular stimulus. These studies neglected the concomitant Coriolis force actions on the head/neck system. We assessed non-vestibular Coriolis effects by measuring arm and leg movements made in the center of a rotating room turning at 10 rpm and found that movement endpoints and trajectories are initially deviated; however, subjects readily adapt with 10–20 additional movements, even without seeing their errors. Equilibrium point theories of motor control errantly predict that Coriolis forces will not cause movement endpoint errors so that subjects will not have to adapt their reaching movements during rotation. Adaptation of movement trajectory acquired during Coriolis force perturbations of one arm transfers to the unexposed arm but there is no intermanual transfer of endpoint adaptation indicating that neuromotor representations of movement endpoint and trajectory are separable and can adapt independently, also contradictory to equilibrium point theories. Touching a surface at the end of reaching movements is required for complete endpoint adaptation in darkness but trajectory adapts completely with or without terminal contact. We have also made the first kinematic measurements of unconstrained head movements during rotation, these movements show rapid adaptation to Coriolis force perturbations. Our results point to methods for achieving full compensation for rotation up to 10 rpm.     

Effects of Polyethyleneglycol Chain Length and Phospholipid Acyl Chain Composition on the Interaction of Polyethyleneglycol-phospholipid Conjugates with Phospholipid: Implications in Liposomal Drug Delivery

Purpose. The purpose of this study was to investigate polyethyleneglycol(PEG)-phosphatidylethanolamine(PE) conjugate interaction with phospholipid bilayers, in an attempt to explain the dependence of liposome circulation time on formulation. Methods. Differential scanning calorimetry, electron microscopy, dynamic light scattering and NMR were the major methods used in the study. Results. Mixtures of PEG-phospholipid conjugates and phosphatidylcholine existed in three different physical states: a lamellar phase with components exhibiting some miscibility, a lamellar phase with components phase separated, and mixed micelles. Beyond 7 mol% of PEG(l,000–3,000)-dipalmitoyl phosphatidylethanolamine (DPPE), and 11 mol% PEG(5,000)-DPPE in dipalmitoyl phosphatidylcholine (DPPC), a strong tendency towards mixed micelle formation was observed. All concentrations of PEG(12,000)-DPPE and PEG(5,000)-DPPE beyond 8 mol% formed phase separated lamellae with phosphatidylcholine. Decreasing the acyl chain length from C_16:0 to C_14:0 caused a decrease in tendency towards micelle formation and phase separation. These tendencies increased upon increasing acyl chain length to C_18:0. Phase separation was at least partly due to PEG chain-chain interaction. This was supported by an increased fraction of PEG chains exhibiting a fast NMR transverse relaxation in DPPC/PEG(5,000)-DPPE mixtures as compared to that in distearoyl phosphatidylcholine (DSPC)/PEG(5,000)-dioleoyl-PE (DOPE). Conclusions. These phenomena are discussed in relation to both bilayer and steric stabilization of liposomes, and the lack of prolonged circulation with certain formulations is discussed.     

频闪喉镜对声带病理情况观察的研究

对1997年以来423例病态喉的频闪喉镜表现进行分析,结果显示声带有病理改变者其粘膜波、振幅、闭合相、运动周期性、对称性均有不同程度的变化,这种变化能直接反映声带病变的深度及范围,对喉部疾病的诊断、鉴别诊断、治疗指导及预后评价具有重要意义.     

Fragmentation process of current laser lithotriptors

Background and Objective: Flashlamp pumped dye (FPDL), Q-switched Nd:YAG, and alexandrite lasers are the most clinically used laser lithotriptors. Although calculi are fragmented by laser induced mechanical stresses for all lithotriptors, different fragment sizes and fragmentation efficiencies have been reported. In this work the effect of the pulse duration and pulse shape on the fragmentation processes is studied. Material and Methods: Fragmentation processes are characterized on model stones and on sensing target fibers. Stone fragmentation and cavitation bubble generation are observed by video flash photography. Shock wave occurrence and strength are monitored with an hydrophone. Results: For the FPDL, stone fragmentation is induced by the collapse of the large cavitation bubble formed. For the Q-switched Nd:YAG, fragmentation is already observed during the laser pulse, at the plasma onset, although further fragmentation can occur at the bubble collapse. For pulse durations corresponding to the alexandrite, an intermediate fragmentation regime is observed. Conclusion: For the first time the physical basis of the observed differences in the fragmentation efficiencies of current laser lithotriptors is described. For nanosecond durations the fragmentation processes are governed by plasma induced shock waves. On the contrary, for microsecond durations fragmentation is governed by cavitation. The high fragmentation efficiency of microsecond lasers is due to a high laser energy transfer into cavitation. © 1995 Wiley-Liss, Inc.     

The relation between conduction velocity and axonal length

Motor evoked potentials (MEPs) obtained by electrical root stimulation and F waves were used to examine the proximal nerve conduction velocity (CV) to tibialis anterior (TA), extensor digitorum brevis (EDB), flexor carpi radialis (FCR), and abductor pollicis brevis (APB) muscles in 40 humans. By subtracting motor latencies obtained by stimulating the peripheral nerve at the same point from the F-wave and MEP latencies, we could measure the CV over identical proximal segments. It was found that proximal CV to TA and FCR was significantly higher than to EDB and APB, respectively. Combining the data of the proximal CV to all four muscles in relation with axonal length resulted in a highly significant inverse relationship (r² = 0.77). Thus the axonal length explained to a large extent the higher CV of the arm nerves and also the inverse relation between body height and CV. The distal CV was always lower than proximal CV; however, there was no support for an additional effect of this gradient in explaining the relationship between CV and height since it was constant for all body heights. © John Wiley & Sons, Inc.     

不同剂量体外冲击波治疗肱骨外上髁炎的疗效对比

目的 比较不同能流密度的体外冲击波(extracorporeal shock wave, ESW)治疗肱骨外上髁炎(lateral epicondylitis, LE)的短期临床疗效,探索ESW的最佳治疗剂量。方法 将120例LE患者分为A、B、C和D 4组,均使用ESW治疗4周,各组的能流密度分别为0.06、0.08、0.10、0.12 mJ/mm²。分别在治疗前及治疗后4、24及48周,比较4组患者疼痛视觉模拟量表(visual analogue scale, VAS)评分、肱骨外上髁炎功能评估(patient-rated tennis elbow evaluation, PRTEE)评分及末次随访患者满意度和复发率。结果 按时间点比较,各组VAS评分治疗前最高,治疗后48周降至最低(P<0.05),4组患者满意度及复发率比较差异无统计学意义(P>0.05),但C组患者满意度(96.67%)明显高于A组(80%),差异具有统计学意义(P=0.04)。按组间比较观察,治疗前各组患肘VAS评分差异无统计学意义(P>0.05);治疗后4、24和48...