细胞膜和细胞骨架在细胞受力过程中的保护作用

力作用下的细胞保护反应是细胞机械力转导研究中的一个重要领域。细胞膜维持细胞内离子平衡，并通过牵张活化离子通道和机械力敏感酶调控力诱导的细胞骨架重排对细胞骨架产生保护作用；而细胞骨架给细胞膜提供结构支撑、加强受力部分的皮层网络结构、调控机械力敏感离子通道，在受力破坏后的细胞膜重新封闭的过程中也发挥着潜在的作用。就细胞膜和细胞骨架在细胞受力过程中的保护作用进行综述。     

Patient-specific mechanical properties of a flexible multi-body model of the scoliotic spine

The flexibility of the scoliotic spine is an important biomechanical parameter to take into account in the planning of surgical instrumentation. The objective of the paper was to develop a method to characterisein vivo the mechanical properties of the scoliotic spine using a flexible multi-body model. Vertebrae were represented as rigid bodies, and intervertebral elements were defined at every level using a spherical joint and three torsion springs. The initial mechanical properties of motion segments were defined fromin vitro experimental data reported in the literature. They were adjusted using an optimisation algorithm to reduce the discrepancy between the simulated and the measured Ferguson angles in lateral bending of three spine segments (major or compensatory left thoracic, right thoracic and left lumbar scoliosis curves). The flexural rigidity of the spine segments was defined in three categories (flexible, nominal, rigid) according to the estimated mechanical factors (α). This approach was applied with ten scoliotic patients under-going spinal correction. Personalisation of the model resulted in an increase of the initial flexural rigidity for seven of the ten lumbar segments (1.38≤α≤10.0) and four of the ten right thoracic segments (1.74≤α≤5.18). The adjustment of the mechanical parameters based on the lateral bending tests improved the model's ability to predict the spine shape change described by the Ferguson angles by up to 50%. The largest differences after personalisation were for the left lumbar segments in left bending (4⁰±3⁰). Thein vivo identification of the mechanical properties of the scoliotic spine will improve the ability of biomechanical models adequately to predict the surgical correction, which should help clinicians in the planning of surgical instrumentation manoeuvres.     

腰椎板切除对腰椎稳定性影响的实验研究

本文以人体新鲜尸体的完整腰椎为实验标本，采用生物力学测定的方法对切除不同节段腰椎椎板后，腰椎稳定性所受影响进行了定性、定量的研究。从而得出结论，腰椎椎板切除将影响腰椎的稳定性。但稳定性破坏的大小，不随腰椎板节段切除的多少而变化。     

补肾中药佳蓉片对去势小鼠骨丢失的预防作用

目的　研究补肾中药佳蓉片 (JRP)对模型小鼠骨质疏松的影响 .方法　雌性昆明小鼠 6 0只随机分为 6组 ,行去卵巢术或假手术 .处理后分组为 :去卵巢组 (OVX) ,假手术组(Sham) ,去卵巢分为佳蓉片低剂量组 (JRP- L,10 0 mg·d- 1 ) ,佳蓉片中剂量组 (JRP- M,2 0 0 mg· d- 1 ) ,佳蓉片高剂量组 (JRP- H,40 0 mg· d- 1 )和 17β雌二醇组 (E2 ,10 μg·d- 1 ) .手术后灌胃上述药物 2 8d,测定股骨密度、骨生物力学性能、血清碱性磷酸酶 (AL P)、骨钙素 (BGP) .结果　各中药组的股骨骨密度均高于去卵巢对照组 (P<0 .0 5 ) ,与假手术组无差异 ;灌胃中药后骨结构力学参数显著性改善 (P<0 .0 5 ) ,同时 AL P,BGP显著性降低 (P<0 .0 5 ) .结论　补肾中药方剂可预防去卵巢引起的骨丢失 ,改善骨的生物力学性能     

卵巢切除大鼠皮质骨骨密度与生物力学特性

目的：探讨雌激素减少对皮质骨骨密度及生物力学特性的影响,方法：用雌性大鼠去势发色经后骨质疏松症动物模型,观察去势后6wk及12wk大鼠胫骨骨密度及股骨屈服点载荷,载荷／变形,最大应力以及弹性模量的变化,结果：去势6wk骨密度与屈有点载荷,载荷／变形,最在 力以及弹性模量与对照组相比无显差异（P＞0．05）,而去热12wk组骨密度明显低于对照组（P＜0．01）,而屈服点载荷,载荷／变形,最大就力以及弹性模量均低于对照组（P＜0．05）,结论：骨密度和生物力学参数的测量对于骨质疏松症动物模型的建立及治疗骨质疏松症药物疗效的判断有重要的意义。     

沈氏装置稳定性的生物力学评价

评价沈氏经椎弓根内固定装置的生物力学稳定性。方法采用５具新鲜尸体脊柱标本,制造Ｌ１损伤模型,测量并比较标本在完整状态,损伤状态、沈氏装置固定、沈氏装置疲劳及ＣＤ装置固定下的Ｔ１２和Ｌ２之间的三维运动范围,并将沈装置与ＣＤ装置固定下的运动范围进行,经统计学处理,评价沈氏装置的稳定性。     

尸体植入新型人工腰椎间盘腰椎节段生物力学测试

目的:评价植入新型人工腰椎间盘的腰椎节段的稳定性和压缩力学性能。方法:将人工腰椎间盘植入6具新鲜青壮年尸体标本的L4-5椎间隙,进行三维运动范围和压缩刚度测试,并与植入前和髓核切除后进行比较。结果:新型人工腰椎间盘植入后,腰椎节段的三维运动范围为前屈146°,后伸66°,左侧弯79°,右侧弯89°,左轴向旋转85°,右轴向旋转87°。其压缩刚度比髓核切除后高(P<005)。结论:新型人工腰椎间盘植入后既保证了腰椎节段的三维运动功能,又起到了稳定脊柱的功能。     

节段内固定治疗腰椎峡部裂的生物力学研究

在8具成人新鲜腰椎标本上,通过脊柱三维运动实验机,研究了横突棘突钢丝捆绑法、钩螺钉固定法及Buck螺钉固定法对峡部裂腰椎三维稳定性的影响。实验结果表明：三者均能显著地恢复脊柱的稳定性,且三者之间无显著差别。     

Improved Bone Biomechanical Properties in Rats after Oral Xylitol Administration

The effects of 5, 10, and 20% dietary xylitol supplementations on the biomechanical properties, histological architecture, and the contents of collagen, pyridinoline, and deoxypyridinoline in long bones of rats were studied. Tibiae were used for the three-point bending test, and femurs were used for the torsion and loading test of the femoral neck. The 10 and 20% oral xylitol administrations caused a significant increase of tibial stress, femoral shear stress, and stress of the femoral neck as compared with the controls. Parallel, but not significant, effects were also seen in the 5% xylitol supplementation group. No significant differences in strain or Young's modulus of the tibiae were detected between the groups. An increased shear modulus of elasticity in femurs was detected in the 20% supplementation group as compared with the controls. The histomorphometrical data for the secondary spongiosa of the proximal tibia revealed that trabecular bone volume was significantly greater in all dietary xylitol supplementation groups as compared with the controls. The bone volume increased along with increasing xylitol content. No significant differences between the groups were detected concerning the amount of collagen per dry weight of organic matrix, the concentrations of pyridinoline or deoxypyridinoline in collagen, or the ratio of these crosslinks. This suggests no xylitol-dependent selective changes in these structures of bone collagen. In conclusion, dietary xylitol supplementation in rats improves the biomechanical properties of bone and increases the trabecular bone volume dose dependently. Received: 30 January 1997 / Accepted: 1 October 1998     

经单侧椎弓根灌注固化磷酸钙骨水泥和聚甲基丙烯酸甲酯椎体成形的实验效果比较

目的比较经单侧椎弓根灌注自固化磷酸钙骨水泥（autosetting calcium phosphate cement,ACPC）和聚甲基丙烯酸甲酯（polymethylmethacrylate,PMMA）椎体成形的效果.方法用离体连续三节胸腰椎标本共10个,分别测定中间椎体和相邻椎间盘非破坏性载荷下标本运动时的应力、应变和刚度值.造成中间椎体压缩骨折的同时测定其极限载荷和刚度值.然后标本随机分成2组,分别经单侧椎弓根灌注3 mL ACPC和PMMA椎体成形后再同前测试.结果椎体成形术后,两组中间椎体扭转刚度较初始皆有下降,两组之间有显著性差异;两组中间椎体抗压极限载荷较初始都有显著性提高;ACPC组椎体极限刚度不能恢复;PMMA组相邻椎间盘应力显著增加21%左右.结论经单侧椎弓根灌注ACPC和PMMA都能较好恢复椎体的生物力学性能,但在扭转刚度和极限刚度的恢复上灌注PMMA稍好一些.灌注ACPC椎体成形后相邻椎间盘不出现高应力现象和载荷传递异常效应,有望降低相邻椎体继发骨折的发生率.