感受态细胞制备与保存方法的比较研究

目的 :确立一个能制备高转化率感受态细胞并长期维持其感受性的实验方案。方法 :比较CaCl2 法、TSS法、超高效法制备感受态细胞的效果 ,选用三者中较好的方法进一步探讨不同生长期 (OD值 0 .2～ 1.1)的细菌对制备感受态细胞的影响 ,并分别比较了不同冷冻保护剂 (7%DMSO ,10 %甘油 )于 - 2 0℃、- 80℃冰箱保存感受态细胞的效果。结果 :三种方法获得的感受态细胞转化率差异极显著 (P <0 .0 1)。采用超高效法 ,OD值为 0 .36 (或 0 .5 8)时收集菌体可获得 1.1× 10 8的高转化率的感受态细胞 ,以 7%的DMSO为冷冻保护剂保存感受态细胞可维持 10 7以上的转化率 4 0d以上     

诊断学实验教学中形态学标本的保存与制备

在实验诊断学的实验教学中,形态学标本如管型,病理性脑脊液等的来源越来越困难,尤其是在时间上,标本的来源有随机性,而上课时间是固定的,教学质量很难,要解决这个问题,就必须研究标本的保存与人工制备.作者经过多年的探索与实践,获得了一些标本的保存和制备的体会,这样既保证了教学质量,又减轻了寻找阳性标本的难度.     

骨折愈合中骨再生的生物学和生物力学

一、骨再生的生物学1.骨骼的生长和发育骨骼的生长和发育涉及很多细胞和组织的分化和增殖,虽然其过程复杂,却精确有序。在胚胎发育阶段,长骨先形成一个间充质细胞团块,然后软骨化形成软骨基质。随着发育的渐进,软骨细胞肥大,细胞外基质开始矿化,形成初级骨化中心。软骨细胞通过     

2型糖尿病模型GK大鼠骨形态学和生物力学特点观察

目的观察2型糖尿病模型GK大鼠的骨代谢特点以及骨密度和骨生物力学特性的变化。方法采用雄性6月龄GK大鼠10只,以月龄、性别匹配的健康Wistar大鼠作为正常对照。颈静脉取血检测与骨代谢有关的生化指标。DXA法测定股骨和腰椎骨密度,并行股骨三点弯曲实验和腰椎压缩实验。甲基丙烯酸甲酯包埋胫骨干骺端以制备不脱钙骨切片。应用多媒体病理图像分析软件进行骨组织形态计量学分析。结果GK大鼠体重明显低于健康对照Wistar大鼠（P〈0.01）。与对照组相比,GK大鼠血清骨钙素水平明显降低[（4.97±0.49,6.75±0.71）μg/mL,P〈0.01],而抗酒石酸酸性磷酸酶活性明显升高[（17.92±5.23,8.31±2.69）U/L,P〈0.01],但血钙和血磷无明显变化（P〉0.05）;股骨和腰椎骨密度显著降低[（0.16±0.01,0.22±0.02;0.12±0.01,0.16±0.02）g/cm2,P〈0.01];骨强度和腰椎的弹性模量明显降低（P〈0.01）。骨形态学分析显示GK大鼠股骨长度和第五腰椎高度分别降低10.3%和9.5%（P〈0.01）,股骨和腰椎横截面积无明显变化（P〉0.05）。骨组织形态计量学分析显示,GK大鼠骨小梁体积、骨小梁厚度、类骨质表面和厚度明显降低[（15.72±1.18,19.13±1.13）%,（61.91±4.54,74.43±3.63）μm,（18.18±1.25,19.63±1.07）%,（3.68±0.48,4.34±0.35）μm,P〈0.01或0.05],动态参数如矿化表面、矿化沉积率和骨形成率也明显降低[（17.77±1.54,19.56±2.07）%,（1.07±0.22,1.35±0.16;0.20±0.03,0.26±0.04）μm/day,P〈0.05或0.01],而矿化延迟时间显著延长（2.66±0.56,2.12±0.35,P〈0.05）。结论非肥胖的GK大鼠表现有骨量减少和骨折危险性增加;2型糖尿病本身可干扰成骨细胞功能和活性而导致骨重建失衡。     

犬完整骨及骨水泥重建骨缺损微波灭活后的生物力学研究

目的:研究微波消融(microwave ablation)对结构正常及缺损后骨水泥修复重建的犬骨生物力学性能的影响.方法:取成年犬股骨12对,随机分为完整组和重建组,再随机选取每对股骨的一侧作为对照组,另一侧为实验组,试验由此分为四组:完整对照组,完整微波组,重建对照组,重建微波组.然后将每根股骨制作成两个不同的骨标本,分别长3 cm和6 cm.两种微波组的标本均进行微波灭活,两种重建组的标本均制备成缺损模型并行骨水泥修复重建.然后分别对3、6 cm两种标本行压缩和三点弯曲试验.结果:完整对照组与完整微波组之间,重建对照组与重建微波组之间的最大压缩力、最大压缩位移、最大弯曲力及最大挠度等均无显著性差异.结论:微波消融对结构正常的犬骨的生物力学性能无明显影响,且不会加剧对重建犬骨的力学强度的破坏.     

保存介质和温度对西伯利亚鲟卵子短期保存的影响

研究了不同保存介质(体腔液CF、Hepes液、RMS液)、温度(4℃、16℃)和保存时间(4 h、8 h、16 h、24 h)对西伯利亚鲟卵子短期保存的影响.结果显示:保存介质、温度和时间对卵子受精率、孵化率和初孵仔鱼畸形率有显著性影响(P<0.05),受精率、孵化率均随保存时间的延长而下降,畸形率上升.16℃条件下保存卵子受精率、孵化率和畸形率均高于4℃,但4℃下卵子的保存时间较16℃下长.研究表明,采用根据西伯利亚鲟体腔液生化成分配制的Hepes液作为保存介质,于16℃下保存4 h为西伯利亚鲟卵子的最佳保存条件,此时受精率、孵化率和畸形率分别为86.36%、94.74%和0.     

泼尼松灌胃与肌内注射对大鼠骨密度、骨生物力学性能及骨代谢的影响

目的观察泼尼松灌胃与肌内注射两种不同给药方法对大鼠骨密度、骨生物力学及骨代谢的影响。方法将45只SPF级雄性SD大鼠随机分为3组（正常组15只、灌胃组15只、肌内注射组15只）,其中正常组大鼠作为阴性对照,予0.9%生理盐水灌胃2 m L/d;灌胃组大鼠给予泼尼松0.5 mg/（kg·d）灌胃;肌内注射组大鼠给予泼尼松0.5 mg/（kg·d）;12周后测定离体的大鼠椎体骨密度及血清β-CTX、PINP水平变化,采用三点弯曲试验测量股骨皮质骨最大载荷、弹性载荷、断裂载荷等生物力学指标。结果与正常组相比,灌胃组及肌内注射组大鼠椎骨骨密度值均显著性降低（P〈0.05）;与灌胃组相比,肌内注射组大鼠椎骨骨密度显著下降（P〈0.05）;与正常组相比,灌胃组及肌内注射组大鼠股骨的弹性载荷、最大载荷、断裂载荷均显著降低（P〈0.05）,肌内注射组与灌胃组大鼠的弹性载荷、最大载荷、断裂载荷相比差异无显著性（P〉0.05）。与正常组相比,灌胃组及肌内注射组大鼠中血清β-CTX水平均显著升高（P〈0.05）而PINP水平均显著降低（P〈0.05）,与灌胃组相比,肌内注射组大鼠血清β-CTX水平显著升高（P〈0.05）而PINP水平显著降低（P〈0.05）。骨组织切片HE染色显示：肌内注射组大鼠的骨小梁明显纤细疏松,造血组织明显减少,脂肪组织明显增多。结论泼尼松对大鼠的骨密度、骨生物力学及骨代谢指标都有影响,而肌内注射泼尼松比口服对骨密度、骨强度、骨代谢的影响更大,更易造成骨质疏松症。因此,建议临床使用泼尼松时选择口服作为给药方式更安全。     

不同温度及时间对保存血液有效期和质量的影响

目的 :研究不同温度对血液液状保存时保存损伤机制的影响 ,并探讨相应的防范措施。方法 :取 10名健康献血员静脉血 ,混合于CP2D A保存液中 ,均分为 2组 ,分别保存于 0℃和 4℃环境条件下 ,分别于设定的时间 (第2 1d和第 4 2d)以shafiq UR rehman法检测膜磷脂 ,同步法检测Na K ATP酶、纯化PDE法检测CaM、分光光度法检测LPO等指标。结果 :固定温度条件下随时间的延长血液过氧化反应增强 ,保存损伤作用增加 ;同一时期内保存损伤作用随温度的降低而减轻 ,以 4℃组血液老化明显。结论 :血液保存损伤作用随保存期的延长而增强 ,随保存温度的降低而改善 ,并指出血液液状保存所存在的问题与展望。     

改良空心椎弓根钉和钉道强化的生物力学研究

目的:探讨改良空心椎弓根钉、钉道强化技术增强骨质疏松椎体固定强度的效果.方法:通过自行设计并加工的空心侧孔椎弓根螺钉、空心钉道强化装置向钉道内灌注骨水泥以强化椎弓根钉道.选取4具骨密度在(0.715±0.13)g/cm2的老年脊柱标本(L1-L4),共16个椎体,32个椎弓根,随机平均分成四组,设计四种固定方法.Ⅰ组:普通椎弓根螺钉(conventional pedicle screw,CPS),Ⅱ组:CPS+钉道内灌注骨水泥,Ⅲ组:空心侧孔椎弓根螺钉+骨水泥灌注,Ⅳ组:空心钉道强化装置灌注骨水泥+CPS.骨水泥完全凝固后测每个椎弓根螺钉的最大轴向拔出力.结果:四组的最大轴向拔出力分别为:Ⅰ组为(458±81)N,Ⅱ组为(596±107)N,Ⅲ组为(828±133)N,Ⅳ组为(857±155)N.Ⅲ、Ⅳ两组的最大轴向拔出力高于Ⅰ、Ⅱ两组(P＜0.01),Ⅱ组的最大轴向拔出力高于Ⅰ组(P＜0.05),Ⅲ、Ⅳ两组之间差异无统计学意义(P＞0.05).结论:自行设计的空心侧孔椎弓根螺钉、空心钉道强化装置分别与骨水泥联合应用行钉道局部强化可明显增强椎弓根螺钉在骨质疏松椎体的固定强度.     

一种酶免疫传感器的制备和性能测试

这种酶免疫传感器是采用丝素蛋白溶液将待测抗原(兔IgG)固定在基础电极表面,选用抗体(山羊抗兔IgG-HRP)与其识别结合。利用H2O2将抗原抗体结合的电位响应信号放大而检测抗原的浓度。该传感器测定抗原的最低检测浓度1.0×10-10 mol/L,线性范围1.0×10-8~1.0×10-10 mol/L,响应时间为10s。通过电泳的方法加速抗原抗体的识别结合,反应时间由原来的90min缩短到30min,这在国内外鲜有报道。这种以固定化抗原结合酶标抗体量的多少作为检测抗原标准的新型酶免疫传感器,在临床检测、生物医学研究等领域将会有广阔的应用前景。     

实验性羊胫骨骨折愈合生物力学研究

本实验用山羊10只,线锯造成胫骨中部骨折,夹板固定。于术后2、4、6周分别处死动物。测量其胫骨骨折愈合的极限弯曲载荷。结果表明:(1)术后第2周,因为纤维性骨痂,无弯曲载荷测量;(2)术后第4周,极限弯曲载荷是150±24(N),其断裂发生在原骨折线,(3)术后第6周,原骨折线处不再发生断裂,干骺部出现断裂,其极限弯曲载荷为653±55(N)。这些结果对临床骨科是有意义的。     

Development and design of a novel loading device for the investigation of bone adaptation around immediately loaded dental implants using the reindeer antler as implant bed

The assessment of the behavior of immediately loaded dental implants using biomechanical methods is of particular importance. The primary goal of this investigation is to optimize the function of the implants to serve for immediate loading. Animal experiments on reindeer antlers as a novel animal model will serve for investigation of the bone remodeling processes in the implant bed. The main interest is directed towards the time and loading-dependant behavior of the antler tissue around the implants. The aim and scope of this work was to design an autonomous loading device that has the ability to load an inserted implant in the antler with predefined occlusal forces for predetermined time protocols. The mechanical part of the device can be attached to the antler and is capable of cyclically loading the implant with forces of up to 100 N. For the calibration and testing of the loading device a biomechanical measuring system has been used. The calibration curve shows a logarithmic relationship between force and motor current and is used to control the force on the implant. A first test on a cast reindeer antler was performed successfully.     

Influence of teeth, alveoli, and periodontal ligaments on torsional rigidity in human mandibles.

We investigated the influence of teeth, periodontal ligaments, and alveoli on the structural integrity of human mandibles loaded in torsion. Surface bone strain was recorded from the mandibular corpus below the first molar on each of four specimens. These specimens were loaded by an external force that caused primarily torsion about the long axis of the corpus, and bone strain was recorded under the following conditions: 1) all supporting structures intact, 2) all supporting structures intact and the M1 loaded by a simulated bite force, 3) M1 removed and 4) alveolar bone of the M1 removed. For comparative purposes, experiments were also designed to investigate the effects of intermittent holes on the torsional rigidity of a baboon femur. This permitted comparison of the mechanical behavior of the mandibles with that of a more homogeneous bony member. These experiments suggest that the presence of teeth within alveoli has a measurable role in the maintenance of torsional rigidity. The condition of the periodontal ligament also appears to influence these stress-bearing capabilities. Moreover, the alveolar bone supporting the teeth also provides structural support for countering torsional loads. For the specific case of corpus twisting, the mandible does not behave as a member with open or closed sections as predicted by theoretical models. The observed magnitudes of bone strain, however, conform more closely to the predictions generated by a closed-section model.     

Curvature of the forelimb bones of anthropoid primates: Overall allometric patterns and specializations in suspensory species

It has previously been reported that brachiating primates, particularly gibbons, are characterized by distinctively straight forelimb long bones, yet no hypotheses have been proposed to explain why straight limb bones may be adaptive to suspensory locomotion. This study explores quantitatively the curvature of the long bones in 13 species of anthropoid primates and analyzes the functional consequences of curvature in biomechanical terms. These analyses demonstrate that, whereas the humeri of gibbons and spider monkeys are functionally less curved than those of other taxa, the ulnae of brachiators are neither more nor less curved than those of other anthropoids, and the gibbon radius is far more curved than would be predicted from body size alone. The humerus is likely significantly less curved in brachiators because of its torsion-dominated loading regime and the greatly increased stress magnitude developed in torsionally loaded curved beams. The large curvature of the radius is localized in the region of attachment of the supinator muscle. Analysis presented here of muscle mass allometry in catarrhines demonstrates that gibbons are characterized by an extremely massive supinator, and the large radial curvature is therefore most likely due to forearm muscle mechanics. This study also demonstrates that the overall pattern of limb bone curvature for anthropoids is distinct from the pattern reported for mammals as a whole. This distinctive scaling relationship may be related to the increased length of the limb bones of primates in comparison to other mammals.     

The Effect of Long-Term Extremely Low-Frequency Magnetic Field on Geometric and Biomechanical Properties of Rats' Bone

Bone is composed of a mineral matrix reinforced by a network of collagen that governs the biomechanical functions of the skeletal system in the body. The purpose of the study was to investigate the possible effect of extremely low-frequency magnetic field (ELF-MF) on geometric and biomechanical properties of rats' bone. In this study, 30 male Sprague-Dawley rats were used. The rats were divided into three groups: two experimental and one control sham. The first and second experimental group (n=10) were exposed to 100?μT and 500?μT-MF during 10 months, 2?h a day, respectively, and the third (sham) (n=10) group was treated like experimental group except ELF-MF exposure in methacrylate boxes. After ELF-MF and sham exposure, geometric and the biomechanical properties of rats' bone, such as cross-sectional area of the femoral shaft, length of the femur, cortical thickness of the femur, ultimate tensile strength (maximum load), displacement, stiffness, energy absorption capacity, elastic modulus, and toughness of bone were determined. The geometric and biomechanical analyses showed that a significant decrease in rats exposed to 100?μT-MF in comparison to sham and 500?μT-MF exposed rats about the values of cross-sectional area of the femoral shaft (P<0.05). Maximum load increased in 100?μT-MF and 500?μT-MF exposed rats when compared to that of the sham rats (P<0.05). The cortical thickness of the femurs of MF-exposed rats (100?μT and 500?μT) were significantly decreased in comparison to that of sham groups' rats (P<0.05 and P<0.001). However, no significant differences were found in the other biomechanical endpoints between each other groups, such as: length of the femur, displacement, stiffness, energy absorption capacity, elastic modulus, and toughness of bone (P>0.05). These experiments demonstrated that 100?μT-MF and 500?μT-MF can affect biomechanical and geometrical properties of rats' bone.     

Analysis of the independent power of age-related,anthropometric and mechanical factors as determinants of the structure of radius and tibia in normal adults. A pQCT study

To compare the independent influence of mechanical and non-mechanical factors on bone features, multiple regression analyses were performed between pQCT indicators of radius and tibia bone mass, mineralization, design and strength as determined variables, and age or time since menopause (TMP), body mass, bone length and regional muscles’ areas as selected determinant factors, in Caucasian, physically active, untrained healthy men and pre- and post-menopausal women. In men and pre-menopausal women, the strongest influences were exerted by muscle area on radial features and by both muscle area and bone length on the tibia. Only for women, was body mass a significant factor for tibia traits. In men and pre-menopausal women, mass/design/strength indicators depended more strongly on the selected determinants than the cortical vBMD did (p<0.01-0.001 vs n.s.), regardless of age. However, TMP was an additional factor for both bones (p<0.01-0.001). The selected mechanical factors (muscle size, bone lengths) were more relevant than age/TMP or body weight to the development of allometrically-related bone properties (mass/design/strength), yet not to bone tissue “quality” (cortical vBMD), suggesting a determinant, rather than determined role for cortical stiffness. While the mechanical impacts of muscles and bone levers on bone structure were comparable in men and pre-menopausal women, TMP exerted a stronger impact than allometric or mechanical factors on bone properties, including cortical vBMD.     

The mechanobiological effects of periosteal surface loads

We have developed an improved mechanobiological model of bone morphogenesis and functional adaptation that includes the influences of periosteum tension and pressure on bone formation and resorption. Previous models assumed that periosteal and endosteal bone deposition and resorption rates are governed only by the local intracortical daily stress or strain stimulus caused by cyclic loading. The new model incorporates experimental findings that pressures on periosteal surfaces can impede bone formation or induce bone resorption, whereas periosteal tensile strains perpendicular to bone surfaces can impede bone resorption or induce bone formation. We propose that these effects can produce flattened or concave bone surfaces in regions of periosteal pressure and bone ridges in regions of periosteal tension. The model was implemented with computer simulations to illustrate the role of adjacent muscles on the development of the triangular cross-sectional geometry of the rat tibia. The results suggest that intracortical stresses dictate bone size, whereas periosteal pressures may work in combination with intracortical stresses and other mechanobiological factors in the development of local bone cross-sectional shapes.     

齿状突几何参数、骨密度与生物力学性质的相关性研究

目的:齿状突骨折是颈椎的严重损伤,其中大部分需要行前路螺钉内固定术治疗,齿状突的几何参数对螺钉的选择起决定性作用,其骨密度则影响螺钉对骨质的把持力,齿状突固有的生物力学性质对齿状突骨折固定效果进而对骨折愈合有较大影响,基于以上考虑,本课题分析并比较了几何参数、骨密度与生物力学性质的相关性,评价其指导临床应用的意义。方法:将15例经福尔马林浸泡的国人枢椎标本剔除周围软组织,分别测量并分析各个标本的几何参数、骨密度以及扭转刚度、剪切刚度、拉伸刚度等生物力学性质的特点,并比较它们之间的相关性。结果:齿状突为一椭球形结构,难以容纳两枚内固定螺钉,齿状突的几何参数、骨密度和生物力学性质之间没有相关性。结论:临床上在对齿状突骨折采用螺钉内固定前需要了解齿状突的解剖结构并据此选取适当尺寸的螺钉,应根据齿状突基底部的横径选择螺钉的直径,根据基底部到前唇的距离选择螺钉光滑段的长度,根据枢椎高度选择螺钉长度,齿状突的几何参数、骨密度和齿状突的生物力学性质之间并无相关性,并不能根据齿状突几何参数、骨密度来预测其生物力学强度进而预测内固定的初始稳定性。