不同强度静磁场对成骨细胞细胞骨架改建的影响

背景：静磁场对成骨细胞增殖活性、细胞因子分泌及碱性磷酸酶表达等功能活性影响的机制尚不清楚。 目的：观察不同强度静磁场加载对成骨细胞骨架改建和细胞骨架蛋白表达的影响。 方法：取新生24 h内SD大鼠颅骨进行成骨细胞的培养和鉴定。采用静磁场加载装置对体外培养的成骨细胞进行0,8,50,160 mT的静磁场加载,分别于静磁场加载24,48,72 h应用BODYPY-Phaloidin进行成骨细胞骨架染色,激光扫描共聚焦显微镜和图像处理软件Image J测定细胞骨架蛋白的荧光强度。 结果与结论：8,50,160 mT静磁场加载24,48,72 h,荧光标记的成骨细胞骨架蛋白向细胞核周围集中,荧光强度增强(P < 0.05),其中经50 mT静磁场加载的成骨细胞骨架蛋白的荧光最强。说明一定强度的静磁场可以影响成骨细胞骨架的改建和重组。     

钛颗粒负荷对成骨细胞白细胞介素6生成的影响

磨损碎屑颗粒所诱发的无菌性松动是人工关节置换术后最常见的并发症.研究表明,假体-骨界面的骨组织细胞吞噬磨屑颗粒后,以自分泌或旁分泌的方式释放细胞间介质因子,而引起假体旁骨改建紊乱,导致假体松动.为了探明不同直径的磨屑颗粒对细胞释放细胞间介质因子的影响,本研究采用3种不同直径(mean sizeφ0.9 μm、φ2.7μm、φ6.9 μm)的钛颗粒,在浓度分别为0.25wt%,0.1wt%,0.05wt%下与兔成骨细胞共孵育4、8、12、24、36、48 h后,检测各组细胞白介素6(IL-6)分泌的变化情况.结果表明,3种钛颗粒均能刺激成骨细胞分泌IL-6因子,但其上调作用因不同直径,不同负荷浓度,不同负荷时间而有所不同.随着浓度增加和时间的推移,φ2.7μm和φ6.9 μm钛颗粒对IL-6生成的上调作用持续升高,而φ 0.9 μm钛颗粒的上调作用却呈先升高后快速下降的双相变化过程.结果提示磨屑颗粒能明显刺激细胞释放细胞间介质因子IL-6,而颗粒直径大小不同,上调IL-6的程度有所不同,使得细胞间介质因子影响假体旁骨改建紊乱的机制有所不同,这种由细胞因子介导的信号传递机制若进一步深入研究必将有助于人工关节材质的优化选择及临床预防用药指导.     

金属离子对人工关节松动影响的相关研究

目的探讨人工关节腐蚀磨损等产生的金属离子钴（Co2＋）、铬（Cr3＋）对人工关节无菌性松动的影响,以寻求防治假体周围骨溶解的方法。方法体外培养小鼠单核/巨噬细胞（RAW264.7）,用Co2＋、Cr3＋分别干预单核/巨噬细胞,将细胞分为3组：阴性对照组为单纯单核/巨噬细胞,铬离子组为单核/巨噬细胞＋500mg/LCr3＋,钴离子组为单核/巨噬细胞＋10mg/LCo2＋。分别在12h、24h、48h用MTT方法检测三组细胞活性及用半定量逆转录-聚合酶链反应（RT-PCR）方法测定单核/巨噬细胞表面RANKmRNA的表达量。结果 MTT显示与阴性对照组相比,钴离子组和铬离子组中的单核/巨噬细胞在12h、24h、48h的细胞活力明显下降。（RT-PCR）方法测定钴离子组和铬离子组中的单核/巨噬细胞RANKmRNA与阴性对照组相比,在12小时表达均增强（〈0.05）,24小时均达到高峰（〈0.05）,48小时相对24h表达都有所下降（﹤0.05）。结论钴离子和铬离子对单核/巨噬细胞有细胞毒性,且能够诱导单核/巨噬细胞RANKmRNA的表达,从而加重假体周围骨溶解和假体松动。     

不同直径的钛颗粒负荷对成骨细胞分化和矿化能力的影响

植入假体磨损碎屑颗粒所引起的无菌性松动是假体周围骨形成与骨吸收过程失衡的结果 ,成骨细胞所参与的骨形成代谢受阻在这一病理生理过程中起着重要作用 ,而且不同大小的磨屑颗粒对骨形成影响的机制应该有所不同。为了探讨磨屑颗粒对成骨细胞骨形成能力的影响机制 ,本研究分析了 3种不同直径的钛颗粒负荷对成骨细胞分化成熟和矿化能力的影响。结果显示 ,未经钛颗粒负荷的成骨细胞表现出良好的分化和矿化能力 ;Φ6 .9μm钛颗粒负荷对成骨细胞分化和矿化能力的抑制作用并不显著 ,而 Φ2 .7μm和 Φ0 .9μm钛颗粒负荷 ,尤其是Φ 0 .9μm的抑制作用非常明显 ,且具有一定的时间依赖性。透射电镜观察显示 ,颗粒负荷后成骨细胞的骨形成功能异常与其超微结构改变有关。结合我们以前的工作 ,提示磨屑颗粒直径对骨形成的影响在无菌性松动中发挥至关重要的作用 ,亚微米级颗粒与骨形成受抑有明显的相关性 ,而大直径颗粒可促进骨吸收 ,有关不同颗粒直径对骨形成影响本质的更深入研究必将促进无菌性松动机制的早日阐明。     

静磁场作用下大鼠牙槽骨中前列腺素E2变化的研究

目的：通过对大鼠在静磁场和非磁场作用下其牙槽骨的内源性前列腺素Ｅ２随时间变化的对比研究,了解在静磁场作用下,大鼠牙槽骨中前列腺素Ｅ２含量的时间变化性。方法：放射免疫法检测２０只加静磁场、２０只加非磁场和４只空白对照的大鼠牙槽骨中前列腺素Ｅ２的含量,探讨静磁场对大鼠牙槽骨的内源性前列腺素Ｅ２的变化的影响。结果：未受力时,大鼠的牙槽骨内即存在一定数量的前裂腺素Ｅ２。在静磁场作用下,牙槽骨的内源性前列腺     

金属离子诱导人单核细胞凋亡并释放肿瘤坏死因子的实验研究

目的 探讨人工关节磨损产物金属离子钴(Co2 )、铬(Cr3 )对人工关节无菌性松动的影响.方法 将金属离子Co2 、Cr3 分别与人单核细胞共培养,分别于12、24、48小时取细胞上清液,用ELISA法检测上清液中肿瘤坏死因子(TNF-α)含量,并测定细胞悬液中细胞凋亡情况.结果 Co2 、Cr3 均能刺激人单核细胞产生TNF-α且TNF-α量随时间上升,一定时间后达到峰值,随后缓慢下降.而随时间发展,人单核细胞凋亡率逐步升高.结论 金属离子Co2 、Cr3 能通过刺激人单核细胞合成和释放肿瘤坏死因子,诱发人单核细胞凋亡从而引起假体周围骨溶解,进而引起假体松动.     

静磁场作用下大鼠牙槽骨中前列腺素E_2变化的研究

目的 :通过对大鼠在静磁场和非磁场作用下其牙槽骨的内源性前列腺素 E2 随时间变化的对比研究 ,了解在静磁场作用下 ,大鼠牙槽骨中前列腺素 E2 含量的时间变化性。方法 :放射免疫法检测 2 0只加静磁场、2 0只加非磁场和 4只空白对照的大鼠牙槽骨中前列腺素 E2 的含量 ,探讨静磁场对大鼠牙槽骨的内源性前列腺素 E2 的变化的影响。结果 :未受力时 ,大鼠的牙槽骨内即存在一定数量的前列腺素 E2 。在静磁场作用下 ,牙槽骨的内源性前列腺素 E2 在 1h内即开始升高 ,在 6 h时达高峰 ,随即开始下降 ,但速度缓慢 ,2 4h时仍高于正常。加非磁场组前列腺素 E2 的变化趋势同加磁场组 ,但前列腺素 E2 开始反应慢 ,峰值却高于加磁场组。且12 ,2 4h时的前列腺素 E2 水平亦高于加静磁场组。结论 :牙槽骨的内源性前列腺素 E2 的变化与静磁场的生物学效应有关     

旋转磁场及静磁场对人肝癌细胞增殖的影响

目的：利用旋转磁场和静磁场对人肝癌细胞进行作用，探讨磁场对人肝癌细胞增殖的影响。材料和方法：将细胞株HepG2接种于96孔培养板，在37℃、5%CO2恒温培养箱培养24小时后放置于0．2T的旋转磁场（0－10Hz频率可调）和0．2T的静磁场中，作用一定时间后利用MTT法检测细胞增殖情况。结果：短时的旋转磁场作用和长时的静磁作用对HepG2细胞株的增殖无明显影响。     

应加强静磁场生物医学效应的基础及临床应用研究

近年来,静磁场(SMF)保健品和磁疗产品受到国内外市场的广泛欢迎。然而,静磁场对动物和人体到底有何影响,是人们十分关注的问题。本文从细胞、动物实验和人体试验三个层面介绍国内外至今开展的研究工作。这些研究结果不一致,甚至相互矛盾,因此静磁场保健和磁疗产品研发应从剂量学优化、可信安慰对照设立和双盲措施等三方面深入研究,以此获得最优磁场强度和最佳治疗效应。加强静磁场生物医学效应的基础及临床应用研究,为今后的科学应用奠定基础。     

三种波形磁场对大鼠成骨细胞增殖与分化的影响

目的：研究不同波形磁场辐照，对离体大鼠成骨细胞增殖与分化的影响。方法：用矩形、三角形和正弦三种典型波形磁场辐照离体成骨细胞。结果：频率15Hz，幅值5mT，矩形磁场促进细胞增殖（P〈0．01），抑制细胞分化（P〈0．01）;正弦磁场抑制细胞增殖（P〈0．01），促进细胞分化（P〈0．01）；三角彤磁场对细胞增殖和分化的影响尤显著性差异．结论：除强度和频率窗外，还需考虑波形的影响。     

Concentration- and composition-dependent effects of metal ions on human MG-63 osteoblasts

Metal debris from implants has been shown to alter the function of osteoblasts in cell cultures. Its remains unclear, however, if specific forms of released ionic metals are involved in the pathogenesis of periprosthetic osteolysis. We evaluated the relative effects of ionic forms of implant metals by treating human osteoblast-like MG-63 osteosarcoma cells with eight concentrations (0.001-10.0 mM) of Cr(+3), Mo(+5), Al(+3), Ta(+5), Co(+2), Ni(+2), Fe(+3), Cu(+2), Mn(+2), Mg(+2), Na(+2), and V(+3) chloride solutions. The results demonstrated that the metal ions differentially affected osteoblast proliferation, viability, type-I collagen gene expression, and cytokine release. The metal ions were ranked in order from least to most toxic (based on a 50% reduction in viability) as follows: Na < Cr < Mg < Mo < Al < Ta < Co < Ni < Fe < Cu < Mn < V. Metal-induced decreases in osteoblast proliferation were similar in ranking. Nontoxic concentrations of metals had no effect on procollagen alpha1[I] gene expression; only at toxic concentrations did metals produce a decrease in gene expression. The most toxic metals (V, Mn, Fe, and Ni) were also the only metals found to induce IL-6 secretion on a per cell basis (of the cytokines tested, interleukin 6 (IL-6), interleukin beta 1 (IL-1beta), transforming growth factor beta 1 (TGF-beta1), and tumor necrosis factor alpha (TNF-alpha), only IL-6 was detectable in the culture medium after 48 h for any metal at any concentration). Less toxic metals (e.g., Co and Cr) had little effect on IL-6 release, even at high concentrations. In general, metal ions reduced osteoblast function (i.e., proliferation and collagen gene expression) in proportion to the degree of toxicity. These results support the hypothesis that adverse local cellular responses (particularly necrotic responses) associated with metal debris from implanted metallic devices may be due in part to metal ions released from implants or from particulate debris.     

恒定磁场中大鼠成骨细胞的增殖和功能活性

背景：磁场对成骨细胞生物学的影响存在一定的分歧。 目的：探讨不同强度恒定磁场作用不同时间后成骨细胞增殖和功能活性的改变。 方法：用体外培养的SD大鼠成骨细胞第3~5代分别在0,5,22,86,135 mT恒定磁场下培养,观察8,12,24 h后细胞增殖和凋亡变化及细胞上清液中骨钙素及Ⅰ型前胶原C端前肽的表达。 结果与结论：磁场作用8,12 h后,5,22,86,135 mT磁场培养的细胞增殖指数均高于对照组(P < 0.05),作用24 h时,仅5 mT组高于对照组(P < 0.05)。而0,5,22,86,135 mT恒定磁场下培养8,12,24 h的凋亡百分数差异无显著性意义。磁场作用8 h后,22,86,135 mT组骨钙素分泌量均高于对照组(P < 0.05);作用24 h后,135 mT组骨钙素分泌量则明显低于对照组(P < 0.05);而磁场作用8,12 h后,22,86 mT组Ⅰ型前胶原C端前肽分泌量明显高于对照组(P < 0.05),作用24 h后,135 mT组Ⅰ型前胶原C端前肽分泌量则明显低于对照组(P < 0.05)。表明低强度磁场、短时间作用可促进成骨细胞的增殖及成骨物质的分泌,而高强度磁场或磁场暴露时间过长则抑制成骨细胞增殖及成骨物质的分泌。     

The hydrational effect of alkali metal and halide ions on the Rh-anti-Rh system

An examination has been made of the action of alkali metal and halide ions on the Rh-anti-Rh system.

Under conditions in which differences due to electrostatic effects are minimal, there is appreciable variation in the experimental response measured by the Race score. This variation is attributed to hydrational effects of the ions and it is noted that the erythrocyte permeability of halide ions complicates their behaviour.

It is suggested that ionic hydration is an important factor governing the magnitude of the entropy change that accompanies Rh-anti-Rh combination in the first stage reaction.

     

正弦交变电磁场促进体外培养成骨细胞成熟矿化的时间效应

研究正弦交变电磁场(SEMFs)促进体外培养成骨细胞(OB)成熟矿化的时间效应。OB培养后随机分成7组,其中6组用50Hz、1.8mT SEMFs处理,处理时间为每天0.5、1.0、1.5、2.0、2.5和3.0h,1组0h(对照组)。倒置相差显微镜下观察各组细胞形态;48h后检测细胞增殖情况;第3、6、9、12d测定碱性磷酸酶(ALP)活性,第10d茜素红钙化结节染色。磁场处理8d后形成漩涡样分布的钙化节结;各磁场处理组均抑制细胞增殖;ALP活性从0.5～1.5h依次递增,从1.5～3.0h依次递减,1.5h组的ALP活性始终高于对照组(P<0.05),第9d时显著高于其他各磁场处理组(P<0.05);茜素红染色结果显示,1.0、1.5和2.0h组的钙化结节数明显多于对照组。50Hz、1.8mT SEMFs抑制体外培养OB的增殖,但对其分化成熟和矿化过程有显著促进作用,此作用与磁场处理时间有关,尤以1.5h促分化效果最为明显。     

Studies on the melanin-affinity of metal ions

Larsson , B. and H. Tjälve , Studies on the melanin-affinity of metal ions. Acta physiol. scand. 1978. 104. 479–484. Melanin has a capacity to accumulate metal ions in vivo and in rim. In the present study, the relative melanin-affinity of various metal ions has been determined in vim by use of the bisquaternary ammonium compound paraquat as a reference ion. Paraquat has previously been shown to bind to melanin with ionic binding as the dominant mechanism of interaction. The relative melanin-affinity of the metal ions was determined by studying the ability of the metal ions to compete with paraquat for combining with the melanin. Pigment from beef eyes and synthetic melanin prepared from L-DOPA with tyrosinase were used. The affinity for melanin of the metal ions increased with increasing valencies. The order of affinity of the alkali metals was Cs⁺:> Rb⁺ -> K⁺ > Na+ > Li+ and of the alkaline earth metals Ba²+ > Sr²⁺ > Ca²⁺ > Mg²⁺. T1⁺ had a slightly higher affinity than the alkali metals. Pb²⁺ had the strongest affinity of the divalent cations and Cu²⁺ was next in order. Ni²⁺, Co²⁺ and Mn²⁺ showed affinities in the mentioned order. La³⁺ and Gd³⁺, which are chemically similar although the former is diamagnetic and the latter paramagnetic, showed a similar affinity for the melanin, suggesting that it is the chemical and not the magnetic properties which determine the affinity. The studied metal ions showed the same order of affinity for the synthetic melanin as for the eye-melanin, suggesting that the protein moiety of the pigment granules plays a minor role in the binding of the metal ions. Melanin has been shown to contain numerous free carboxyl groups. The results are consistent with the hypothesis that the metal-ion binding of the melanin can be ascribed to a cation-exchange activity with the free carboxyl groups in the melanin polymer as the main binding-sites.     

Static magnetic field effects on bone formation of rats with an ischemic bone model

Effects of a static magnetic field were studied on bone formation using an ischemic rat femur model. Metal rods were prepared from magnetized and unmagnetized samariun cobalt to have tapered structure, both with the same geometrical dimension, and were implanted transcortically into the middle diaphysis of 88 rat femurs. Both sides of the rat femoral artery were ligated to create an ischemic bone model, followed by implantation of the tapered rod to the femur. The bone mineral density (BMD) and weight of the femurs were measured at 1st and 3rd week after implantation.The result at the 3rd week post-implantation revealed that the BMD and weight of the ischemic bone model rats were significantly reduced, compared with that of non-operated femur. It was also found that the magnetized group had significantly higher bone weights than the unmagnetized (p<0.05). The BMD of the rats implanted with the magnetized rods were similar to those of the non-operated (p>0.05). This enhancement of the femoral bone formation of the ischemic rat model by the static magnetic field seems to be due to the improved blood circulation of the femur.     

磁场均匀度对MR图像质量的影响

影响核磁共振（MR）图像质量最基本的部分为磁体，在评价核磁共振扫描仪的众多参数中,主磁场的均匀性是最基本也是最重要的一个衡量指标，该文阐述磁场均匀性对核磁共振成像质量的影响和磁场均匀度测量方法。     

Transient effect of low-intensity magnetic field on human motor control

There is no consensus with respect to how extremely low frequency (ELF) magnetic fields (MF) affect biological systems. However, this information is crucial to establishing new guidelines for: (i) the new design of electronic devices, (ii) working conditions of exposed workers (e.g. electric linepersons), and in a general manner (iii) policies for human risk management. This study evaluates the effect of a sinusoidal 50 Hz, 1000 microT MF centered at the level of the head on human postural tremor of the index finger, using the wavelet analysis method. In addition to the detection of transient events in tremor time series linked with MF, this method was used to evaluate the differences between MF "on" and "off" conditions and between real and sham exposure in a counterbalanced protocol. Results indicate that neither transient events nor "off-on" or "on-off" MF transition effects were present in the postural tremor time series. Surprisingly, an unexpected significant time dependent decrease in tremor average power was noted along the 20s recordings. Interestingly, this effect was significantly more pronounced in the presence of MF. These results suggest a relaxing effect of ELF MF on motor control resulting in an attenuation of postural tremor intensity.