关节液中纳米颗粒的测量对关节疾病诊断的意义

 目的：探讨不同状态下关节液中纳米颗粒与关节疾病种类的相关性。方法：抽取正常人、膝关节骨性关节炎（KOA）和滑膜炎（KTS）患者的关节液，利用准弹性激光散射技术测定关节液中纳米颗粒的粒度大小及其分布，利用相分析电泳光散射技术测定关节液纳米颗粒的Zeta电位，并采用相关分析方法分析纳米颗粒的粒度、Zeta电位与疾病的相关性。结果：KOA和KTS关节液纳米颗粒的平均粒度和Zeta电位都分别显著大于正常对照（P<0.01），粒度和Zeta电位分布曲线比正常对照组的宽（P<0.01）。关节液中纳米颗粒的平均粒度（r_p=0.7972，P<0.01）、Zeta电位（r_p=0.6319，P<0.01）与关节的疾病种类存在很好的相关性。结论：关节液纳米颗粒的粒度和Zeta电位与关节疾病存在显著的相关关系, 可建立起一个关节疾病早期诊断的检测方法。     

PMMA基复合骨板的制备及含胶量对理化性能的影响[]

通过模压成型的方法制备聚甲基丙烯酸甲酯／无机纤维／羟基磷灰石（PMMA／GF／HA）复合骨板。通过改变粉液比控制含胶量，研究了含胶量对力学性能、密度、吸水率的影响。并将复合骨板与人体胫骨的力学性能进行了比较。实验结果表明，通过降低含胶量可有效改善PMMA基复合骨板的脆性，其力学性能与人体胫骨相当。     

硫酸钙/PMMA复合缓释系统的体外药物释放和抗菌性能

目的 探讨硫酸钙/PMMA复合缓释系统的体外抗生素释放规律和抗菌性能,并和含万古霉素的PMMA进行比较。方法 将含万古霉素的硫酸钙颗粒以单层形态嵌入含万古霉素的PMMA的表层,制备硫酸钙/PMMA复合缓释系统。将硫酸钙/PMMA复合缓释系统和含万古霉素的PMMA浸入10 m L模拟体液(SBF)中,在不同时间点进行全量换液,采用高效液相色谱法检测不同时间点全量换液的SBF中的万古霉素浓度。使用上述不同时间点全量换液的SBF进行金黄色葡萄球菌抑菌环试验,以评价硫酸钙/PMMA复合缓释系统的体外抗菌性能,与含有和未含有万古霉素的PMMA进行比较。结果 硫酸钙/PMMA复合缓释系统的万古霉素硫酸钙颗粒在7周内逐渐降解。在不同时间点全量换液的SBF中,硫酸钙/PMMA复合缓释系统的万古霉素浓度均高于万古霉素PMMA的万古霉素浓度(P0.05)。在不同时间点全量换液的SBF抑菌环试验中,硫酸钙/PMMA复合缓释系统的抑菌环均大于含万古霉素PMMA的抑菌环(P0.05)。结论 与含万古霉素的PMMA相比,硫酸钙/PMMA复合缓释系统能够释放更高浓度的万古霉素,并且能够在体外更加有效地抑制金黄色葡萄球菌的生长。     

大鼠单根近球肾小管钠泵活性测定的改良方法

目的：以Doucet介绍的方法为基础，改良了测定大鼠肾脏近端小管Na^＋-K^＋ -ATPase活性的方法。方法：首先，利用自制的玻璃分针能准确而迅速的分离获取近端小管；其次，使用传导性能较好和易于折叠的锡箔纸代替了铝片，简化了孵育和测定过程。结果：改良方法与Doucet建立的经典方法比较，测定结果无显著性差异（P〉0．05）；但对小管长度确定平均耗时和转移合^32 P的孵育液平均耗时明显降低。结论：本文介绍的测定大鼠肾脏近端小管Na^＋-K^＋-ATPase活性的改良方法，减少操作步骤，缩短了操作时间和暴露在放射性环境中的时间；简化并改进了操作条件，降低了实验要求和成本。     

Monte Carlo方法计算补偿材料在放射治疗中的影响

本文用Monte Carlo方法计算在添加不同厚度补偿材料(Paraffin和PMMA)情况下不同能量电子线照射水模体的剂量分布,对所得照射野离轴比和百分深度剂量曲线进行分析讨论.结果表明,补偿材料(Paraffin和PMMA)在放射治疗中可以起到补偿人体不规则的外轮廓,提高皮肤及皮下剂量和调整电子线的剂量分布等作用.     

可注射性硫酸钙/羟基磷灰石骨替代物抗压强度的影响因素

目的分析可注射性硫酸钙／羟基磷灰石骨替代物抗压强度的影响因素。方法用材料力学测试机，①测定含10％、20％、30％、40％、50％质量HA的α-半水硫酸钙分别与欧乃派克按照0．4ml／g的液固比混合后的抗压强度；②测定含40％质量HA的α-半水硫酸钙与欧乃派克按照液固比分别为0．350、0．375、0．400、0．425、0．450或0．475混合后的抗压强度；③测定含40％质量HA的α-半水硫酸钙按照0．4ml／g的液固比与不同的固化液即欧乃派克或蒸馏水混合后的抗压强度。结果当增加液固比，提高羟基磷灰石含量时可注射性硫酸钙／羟基磷灰石骨替代物抗压强度下降，使用固化液欧乃派克或蒸馏水对其抗压强度的影响无显著性差异。结论对可注射性硫酸钙／羟基磷灰石骨替代物抗压强度通过改变影响因素可以满足临床操作的要求。     

碳纤维增强α-磷酸三钙骨水泥的研究

为提高α-磷酸三钙（α—TCP）骨水泥的强度及降低其脆性，将表面改性后的碳纤维（CF）与α—TCP粉复合，制备成α—TCP／CF复合增强骨水泥。通过Ringer’s体液浸泡观察骨水泥快速结晶自固化能力，运用扫描电子显微镜（SEM）及抗压强度测试仪对复合材料浸泡后试样进行断面显微结构分析及抗压强度测试。结果显示，α—TCP骨水泥块浸泡5d后即转化生成片状羟基磷灰石晶体；适量的碳纤维在骨水泥基体中分布均匀，与基体结合性好，可得到抗压强度增强的骨修复材料；当碳纤维的加入重量百分数为0．5％时，复合材料抗压强度达到46．7MPa，比未增强的α—TCP材料提高了22％。     

聚甲基丙烯酸甲酯骨水泥对肺癌细胞毒性作用的体外实验

背景:经皮椎体成形是治疗脊柱转移瘤的一种微创手术方法,但术中注射的聚甲基丙烯酸甲酯(polymethylmethacrylate,PMMA)骨水泥对肿瘤的治疗机制目前尚不明确。目的:分析PMMA骨水泥及其单体对肿瘤细胞的细胞毒作用。方法:将固化期、拉丝期PMMA骨水泥的浸提液及不同质量浓度单体的稀释液与人肺腺癌细胞spc-A1接触培养1,3 d后,采用细胞形态直接观察法和CCK-8比色法测定细胞吸光度(A)值,计算细胞相对增殖率(RGR),评价PMMA骨水泥及其单体对肿瘤细胞的毒性。结果与结论:11 d 1 g/L组、10 g/L组的A值明显小于阴性对照组(P0.01);3 d 1 g/L组、10 g/L组及拉丝期浸提液A值明显小于阴性对照组(P0.05);2结果显示培养1 d 1 g/L组、10 g/L组的A值明显小于阴性对照组(P0.01),细胞相对增殖率为26%-29%,毒性评价为4级;3 d 1 g/L组、10 g/L组的A值明显小于阴性对照组,细胞相对增殖率12%-16%,毒性评价为4至5级;3 d 100 mg/L组、拉丝期PMMA浸提液组的A值明显小于阴性对照组,毒性评价为2级。3结果表明,拉丝期PMMA骨水泥浸提液及PMMA单体质量浓度为100 mg/L-10 g/L时对肿瘤细胞有明显的毒性,说明经皮椎体成形过程中拉丝期PMMA骨水泥注入椎体后其释放的单体可能对肿瘤细胞存在细胞毒作用。     

非对称性二甲基精氨酸保护PCI2细胞拮抗谷氨酸兴奋性毒性的损伤作用

目的：探讨一氧化氮合酶（NOS）抑制剂-非对称性二甲基精氨酸（ADMA）对谷氨酸（Glu）兴奋性毒性损伤PCI2细胞的影响及其机制。方法：用不同浓度的谷氨酸处理PCI2细胞，建立谷氨酸兴奋性神经毒性损伤细胞的实验模型；应用四甲基偶氮唑蓝（MTF）比色法检测细胞存活率；乳酸脱氢酶（LDH）释放试验评价细胞的损伤程度；双氢罗丹明123（DHR）染色后流式细胞仪（FCM）检测细胞内活性氧（ROS）水平；应用试剂盒及分光光度计测定NOS活性和NO水平。结果：谷氨酸（1—6mmol／L）处理PC12细胞24h，可呈剂量依赖性地降低PC12细胞的存活率；在谷氨酸作用PCI2细胞前30min给予ADMA，可明显地抑制谷氨酸引起的细胞存活率降低及LDH释放增加，减少谷氨酸引起的细胞内ROS堆积，抑制谷氨酸过度激活NOS和增加NO的生成。结论：ADMA能显著地减弱谷氨酸对PC12细胞的兴奋性毒性损伤作用；其作用机制可能与抑制NOS活性，减少NO生成，进而减轻细胞内ROS的堆积有关。     

不同分散介质研磨所得纳米珍珠粉的比较

文题释义：纳米材料：物质结构在三维空间中至少有一维处于纳米尺度，或由纳米结构单元构成的且具有特殊性质的材料。在最新的一项纳米碳酸钙标准中，要求颗粒平均粒径≤100 nm。 纳米珍珠粉：以无水乙醇或水作为分散介质球磨细化珍珠粉，研磨介质为0.1 mm氧化锆球，通过扫描电镜、透射电镜、X射线衍射仪检测分析珍珠粉粒径，珍珠粉平均晶粒、平均粒径<100 nm，属于纳米材料。 背景：为了保留更多的有机质及材料生物学活性，需通过物理方法研磨细化珍珠粉。球磨法可以最大限度地保留珍珠粉中的有机质及其活性，而不同分散介质球磨制备的纳米材料效果不同。 目的：对以蒸馏水和无水乙醇两种分散介质研磨所得的纳米珍珠粉进行对比。 方法：分别以无水乙醇与水作为分散介质研磨制备纳米珍珠粉，采用扫描电镜、透射电镜、X射线衍射仪、凯氏定氮法及食品中氨基酸测定等方法比较分析研磨前后的珍珠粉。 结果与结论：①以无水乙醇为分散介质制备的纳米珍珠粉主要为类圆形颗粒，大小不等，主要分布在30-50 nm，平均晶粒20 nm，方解石碳酸钙相对百分比增至7%，蛋白质和氨基酸含量未发生明显变化；②以蒸馏水为分散介质制备的纳米珍珠粉主要为类圆形颗粒，存在较大的条状或块状不规则颗粒，大小不均，平均晶粒30 nm，方解石碳酸钙相对百分比增至10%，蛋白质和氨基酸含量有所减少；③结果表明两种分散介质研磨后珍珠粉粒度有明显差异，以无水乙醇为分散介质研磨的珍珠粉粒度更细更均匀。 ORCID: 0000-0002-9436-3464(毛秋华) 中国组织工程研究杂志出版内容重点：生物材料；骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性；组织工程     

Préparation de microlatex acryliques par polymérisation photochimique de solutions micellaires et de microémulsions

Microlatices of acrylic monomers, in the particle size range of 10–30 nm, were prepared by photopolymerization of micellar systems (monomer-surfactant) and of microemulsions based on monomer-surfactant-cosurfactant. Formation of monomer containing microemulsions is shown for various surfactants in combination with alcohols as cosurfactants and the corresponding phase diagrams are given. Photopolymerization, in the presence of oil-soluble initiators, was investigated for such systems based on cyclohexyl methacrylate (CHMA) and on tetramethylene dimethacrylate (BDMA). Crosslinked and non-crosslinked colloidal polymer particles could be obtained, with a 5–10% solid content of polymer. The variation of particle size, and the molecular weight for non-crosslinked systems, was studies as a function of initiator concentration, and monomer/surfactant ratio. The smallest particles (10–15 nm) are obtained for the system BDMA/lauryl sulfate (LS).     

Suspension polymerization of 2-hydroxyethyl methacrylate in the presence of polymeric diluents: a novel route to spherical highly porous beads for biomedical applications

Spherical, highly porous beads of poly(2-hydroxyethyl methacrylate) (PHEMA) cross-linked with ethylene glycol dimethacrylate (EGDM) were prepared by suspension polymerization of HEMA in concentrated NaCl solutions in presence of toluene, poly(methyl methacrylate) (PMMA) in toluene, and poly(tetramethylene glycol) (PTMG). Magnesium hydroxide prepared in situ in the dispersion medium gave the best stabilization effect for the monomer droplets. In the presence of PTMG, beads having nearly 1.0 mm in diameter could be prepared, while toluene alone as the diluent produced beads of very small size. Removal of PMMA or PTMG from the beads after polymerization using suitable solvents gave rise to highly porous PHEMA microspsheres. Polymerization in the presence of PTMG produced microspsheres with better spherical geometry as compared to those generated in the presence of PMMA. The effect of various factors such as NaCl concentration, concentration of Mg(OH)2, and the concentration of PMMA or PTMG in the monomer phase on the stability of the suspension and the particle size distribution was investigated.     

Mechanical characterization of self-curing acrylic cements formulated with poly(methylmethacrylate)/poly(epsilon-caprolactone) beads

New acrylic-based cements were formulated by replacing a mass fraction of 20% of poly(methyl methacrylate) (PMMA) powder by PMMA/poly(epsilon-caprolactone) (PCL) beads (throughout this article all compositions are given as mass fractions, unless specified otherwise). PMMA/PCL beads containing 10 and 30% PCL were synthesized by suspension polymerization. Cements were prepared by replacing part of the PMMA powder of the formulation by an equivalent mass of PMMA/PCL particles. The influence of the PCL content in the beads on the mechanical behavior was assessed by testing the cements in flexure and compression. The addition of PMMA/PCL particles with 10% PCL content resulted in a marked increase in both flexural modulus and flexural strength related to the plain PMMA beads formulation. This improvement was attributed to a decrease in the cured material porosity. Conversely, by the incorporation of beads with 30% PCL content the flexural properties decreased. This behavior was attributed to the debonding of the particles from the matrix, which was revealed by SEM images. The observed compressive yield strength decrease with the increase of PCL content in the beads was attributed to a low degree of adhesion between the heterogeneous particles and the matrix as well as to the plasticizing effect of the PCL.     

Partial swelling of latex particles with monomers

Two methods are described for experimentally determining the concentrations of monomer in both the aqueous phase and the latex particle phase during partial swelling of latex particles, and therefore also during intervall III of an emulsion polymerization. The ratio of the monomer concentrations in the aqueous phase, both below and at saturation, can be related to the volume fraction of polymer in the latex particles via the Vanzo equation. Comparison of theory and experiments for the methyl acrylate and poly(methyl acrylate-co-styrene) system shows that the monomer partitioning is insensitive to temperature, latex particle radius, polymer composition, polymer molecular weight and polymer cross-linking. Thermodynamic treatment of these and previously published partitioning results shows, at higher volume fractions of polymer, that the conformational entropy of mixing of monomer and polymer is the significant term determining the degree of partial latex particle swelling by monomer. Theoretical predictions of experimental results are quite insensitive to values of the Flory-Huggins interaction parameter and to the latex particle-water interfacial tension. A simple model is developed for the estimation of monomer partitioning which requires only the saturation monomer concentrations in the particle and aqueous phases.     

Encapsulation of Carbon Black by Miniemulsion Polymerization

Full Paper: In this paper the effective encapsulation of carbon black with polymers by co‐sonication of a carbon black dispersion and a typical miniemulsion polymerization recipe is described. The carbon containing polymer particles are analyzed in detail by particle size measurements, transmission electron microscopy, density distributions experiments with the ultracentrifuge, and by nitrogen adsorption. The final particle size was in the range of 50 to 170 nm, the weight ratio polymer to carbon was changed between 20 : 80 and 90 : 10. In all cases, the surface tension of the final dispersion is above the minimal surface tension of SDS indicating the absence of micelles and the incomplete coverage of the polymer coated carbon particles with surfactant. The amount and type of an added hydrophobe needed for osmotic stabilization as well as the type of monomer have a large influence on the encapsulation process. The encapsulation process can be described by a scenario where the fusion/fission by ultrasound splits the monomer droplets, whereas the monomer coated carbon stays intact. The thickness of the monomer film depends on the amount of monomer and has to be optimized since there is an optimal range of monomer layer thickness in order to preserve the morphology. Too low amounts of monomer result in incompletely covered particles which aggregate with polymer whereas too much monomer results in the formation of a second species of pure polymer particles. The process can be described as a polymerization in an adsorbed monomer layer created and stabilized as a miniemulsion (“ad‐miniemulsion polymerization”).     

Histologic response to porous PMMA implant materials.

Poly(methyl methacrylate) as used in polymer replica tooth implants was fabricated into 6 X 6 mm cylindrical specimens and cured in either an air oven, pressure pot, autoclave, or microwave oven. Polymer porosity was achieved by means of either 1) intrinsic foaming agents, or 2) compacting different sizes of large beads with a minimum of monomer, with dense PMMA used as a control. Specimens were then implanted in the long bones of baboons. Histology of thin-sectioned and ground specimens from the sacrificed animals revealed complete tissue ingrowth into implanted material made of medium and large PMMA beads, very superficial ingrowth into material containing foaming agents and anorganic bone chips, and no ingrowth into dense PMMA implants. None of the implants were rejected or caused chronic inflammation. The effect on histologic response of the different curing methods could not be distinguished.     

Alumina as a filler for bone cement: a feasibility study

A composite bone cement of Alcoa A-10 Alumina and very finely ground poly(methyl methacrylate) beads (PMMA) was fabricated. It was tested in an attempt to improve on the conventionally used pure PMMA bone cement.

By knowing the densities of the powders and their volumes, the mass of each was calculated for the most efficient packing of PMMA and Al₂O₃ powders and a 65% PMMA: 35% Al₂O₃ ratio by weight composition was determined. This was tested, as well as the pure cement so comparisons could be made. Cylinders for the strength tests were also made of silane treated Al₂O₃.

The compositions were tested for compressive and tensile strengths. The pure PMMA, composite and silane treated composite had compressive strengths of 79.64 ± 13.0, 83.17 ± 4.8, and 71.52±8.6 MPa and the tensile strengths were 6.69 ±0.6, 5.12 ±0.3, and 7.12±0.5 MPa respectively. Also the 65%–35% PMMA-Al₂O₃ composite required 64% less monomer for mixing than did the pure cement which is thought to be better for tissue healing. The maximum temperature attained from room temperature was 110°–115°C for both cements. The composite took 6.5 min longer to reach its peak temperature than did the pure cement. The bone cements were implanted for one week in a rabbit and both compositions seemed acceptable by the tissue.     

Self-curing acrylic formulations containing PMMA/PCL composites: properties and antibiotic release behavior

Partially biodegradable acrylic composites containing poly(methyl methacrylate)-poly(epsilon-caprolactone) (PMMA/PCL) systems were prepared by mixing the corresponding PMMA/PCL beads (89:11, 86:14, 83:17, and 77:23 weight ratio) used as solid phase with methyl methacrylate (MMA) (liquid phase) in a solid/liquid ratio of 1.5:1. The physical and chemical microheterogeneity of these beads influenced significantly the curing parameters, because several aspects involved in the polymerization reaction are closely related to both morphology and size distribution of the particles. In vitro behavior was studied by immersion in simulated body fluid at pH = 7.4 and 37 degrees C for more than 8 weeks and the composition was followed by 1H-nuclear magnetic resonance spectroscopy. Approximately 2% wt/wt weight loss was observed after a period of 8 weeks for the composites richest in PCL. Mechanical properties of the dry and wet specimens were evaluated by compressive and tensile tests. In all cases, the presence of PCL in the composites provided a significant decrease in both compressive strength and elastic modulus compared with plain PMMA. Tensile and compressive strength also decreased significantly after 2 weeks of immersion in simulated body fluid compared with dry specimens. The self-curing composites based on PMMA/PCL beads and loaded with 3% wt/wt vancomycin were evaluated as carriers for local release of antibiotics. The composite prepared with beads of PMMA/PCL ratio 86:14 was the most effective. It eluted 64% of the initial drug within the first 5 h, allowing progressive release of nearly the total amount of the initial drug (90%) in approximately 2 months. The results obtained suggest that the described composites can be suitable for antibiotic release in non-load bearing graft applications.     

Thermodynamics of swelling of latex particles with two monomers

The partitioning of two monomers between the latex particle, monomer droplet and aqueous phases of an emulsion polymer latex are measured at saturation swelling of the latex particle phase (corresponding to intervals I and II of an emulsion polymerization). The monomer and polymer types are varied systematically and the experiments are performed at two temperatures. The results of these experiments correspond well to a simplified thermodynamic theory of the saturation swelling of an emulsion polymer with two monomers, in which it is realized that the fraction of one monomer is equivalent in the latex particle and monomer droplet phases. Further, it is shown that Henry's law holds for monomers, both in the absence and in the presence of swollen latex particles. A simple empirical relationship is developed whereby the concentration of two monomers at any ratio can be calculated from the individual saturation concentration of the two monomers in the latex of interest.     

Significance of the type and the size of biomaterial particles on phagocytosis and tissue distribution

Particulates generated by dissolution or wear of injected or implanted biomaterials may migrate into various tissues and lead to activation of the host's inflammatory and immune responses. The purpose of this study was to evaluate the relevance of size and chemical composition of biomaterial particles on the pattern of particle distribution in host tissues. Adult female B6C3F1 mice were injected intraperitoneally with polymethylmethacrylate (PMMA) particles (size 1.4 and 6.4 micro in diameter) and polystyrene (PS) particles (size 1.2, 5.2, and 12.5 micro in diameter), and euthanized 1, 7, and 28 days later. Peritoneal exudate cells (PECs) were collected and the number of cells and percentage of actively phagocytic cells was determined. Macroscopic examination of the tissues in the peritoneal cavity peritoneum revealed visible accumulations of the colored PS particles in the adipose tissues adjacent to the spleen and pancreas, and caudal to the stomach. Distribution of the PS particles appeared similar regardless of the particle size. The location of PMMA particles, which were not colored, could not be distinguished from host tissue and could not be observed in this manner. Intensive phagocytosis of the small and medium sized particles by peritoneal macrophages was observed on day 1, and was diminishing by day 7 after injection. The largest PS particles (12.5 micro) were not engulfed by the peritoneal macrophages. Histological examination of the spleen, lymph nodes, and the adjacent adipose tissues revealed a marked difference in the deposition patterns of the two polymers used. PS particles, regardless of size, were accumulated primarily in the white adipose tissues adjacent to the spleen and pancreas gland, but very few particles were observed in the splenic tissue. On the other hand, mice injected with PMMA particles of either size had enlarged and activated spleens with marked deposits of particles in the red pulp. These results indicate that these PS and PMMA particles induce different patterns and intensities of the host response. The chemical makeup of the particle is more important in the distribution pattern than is the size of the particle.