一种具有微观仿生结构的定制化下颌骨植入体

为了使下颌骨人工植入体具有定制化的外形，并使其具有一定的生物活性及与人骨内部哈弗氏管和福克曼管类似的三维微观通道，提出了利用快速原型制造仿生下颌骨替代物的方法。该方法首先利用快速原型技术快速准确地制作出与人骨形状相匹配的人工植入体(模型)及内部三维仿生网架，而后运用铸钛技术完成植入体钛框架的最终成型，钛网内的三维仿生网架被复合有骨形态发生蛋白的磷酸钙骨水泥所包绕。该项研究结果不仅利用快速原型制作出仿生下颌骨人工植入体，还成功地投入临床应用。结论：虽然仅以下颌骨为例，但快速原型适宜于所有仿生人工植入体的定制化制造。     

CAD/CAM/Robotic集成方法设计与制作生物型股骨柄假体

背景:生物型股骨柄假体无菌松动是全髋关节置换失败的主要因素,减少无菌松动的先决条件是增加股骨柄假体在股骨髓腔中的填充率。目的:得到定制式股骨柄假体在髓腔中的填充率,验证计算机辅助设计/计算机辅助制造/工业机器人加工(CAD/CAM/Robotic)集成方法和机器人磨削的有效性。方法:利用CT数据重建股骨髓腔三维模型,在此三维模型基础上设计股骨柄假体的柄体,依据标准直柄股骨柄假体近端模型设计股骨柄假体的其余部分。将设计的股骨柄假体模型导入CAD/CAM/Robotic集成系统生成机器人磨削轨迹,利用该轨迹对股骨柄假体进行磨削加工。将加工好的股骨柄假体与股骨髓腔匹配,分析股骨柄假体在髓腔中的填充率。结果与结论:实验结果表明,定制式股骨柄假体在髓腔中有良好的填充率,髓腔的解剖结构可以阻止股骨柄假体的扭转,获得股骨柄假体在髓腔中的稳定固定。     

多孔HA/PU复合支架材料生物相容性的评估

进行了三维多孔立体结构的纳米羟基磷灰石/聚氨酯(HA/PU)复合支架材料体外细胞培养和体内肌肉埋植实验研究,评估材料的生物相容性。实验选用SD大鼠的骨髓基质干细胞(BMSCs)和健康的SD雌性大鼠,进行细胞相容性、形态学观察和组织学切片分析。HA/PU支架材料的多孔性为细胞的生长提供了良好的微环境,细胞在内部贴壁爬行、增殖并分化,细胞毒性为零级,材料与周围组织有良好的结合,降解的空间有结缔组织纤维长入。实验表明,HA/PU复合支架材料具有良好的细胞亲和性和组织学相容性,可作为一类新型组织工程支架材料。     

多孔预置管道股骨头坏死髓芯植入体的设计与制造

参照人体松质骨及皮质骨内管道的解剖结构,设计多孔预置血管管道新型的早期股骨头坏死修复植入体模型,并利用计算机辅助设计(CAD)建模模拟外科植入过程。通过陶瓷激光光固化技术,直接生成-βTCP陶瓷胚体,并通过烧结等一系列的工艺流程,成型制造出特定形态与微结构的骨生物多孔预置管道植入体。制成试件无碎裂、变形,内部微结构清晰,尺寸与结构与设计模型基本保持一致。孔径等相关参数可满足细胞生长需求。X线衍射分析显示制造过程中无相变及化学反应发生,不影响-βTCP生物性能。试件抗压强度达到23.54 MPa,与松质骨类似。该植入体可以体外复合细胞及生长因子,有望实现早期血管植入,快速建立循环系统及活化的骨坏死区,并可以早期提供足够力学支撑,符合理想骨移植替代物需求,具有广阔的临床应用前景。     

定制型聚羟基乙酸/聚乳酸支架与犬骨髓基质细胞的体外复合培养

背景：聚羟基乙酸、聚乳酸均属于脂肪族聚酯,是一种具有一定机械强度和良好成型性能的生物可降解材料,在体内无毒,不聚积,且有良好的生物相容性。 目的：应用CAD、CAM、快速成型和激光扫描技术等组成的数字医学系统制作聚羟基乙酸/聚乳酸三维仿真的下颌支髁突形态模型,并检测其细胞生物相容性。 方法：通过CT扫描获得犬头颅骨影像信息,以CAD和CAM实现下颌骨髁突形态的三维重建影像,快速成型技术获得下颌骨髁突的树脂阳模。阴阳模转换获得相应石膏阴模,聚羟基乙酸/聚乳酸在阴模内成型。抽取犬髂骨骨髓获得骨髓基质细胞,与定制型聚羟基乙酸/聚乳酸支架在体外复合培养,检测支架材料的生物相容性。 结果与结论：定制型聚羟基乙酸/聚乳酸支架和影像原型比较,当测试点误差小于1.0 mm时,复合率大于95%。通过CAD、CAM、快速成型技术、预压成型技术和激光扫描技术等组成的数字医学系统可实现颅颌面下颌骨髁突形态结构聚羟基乙酸/聚乳酸生物材料的三维仿真。体外复合培养结果表明,定制型聚羟基乙酸/聚乳酸支架和骨髓基质细胞具有良好的生物相容性。     

等离子喷涂羟基磷灰石涂层的骨桥接性研究

羟基磷灰石 (Hydroxyapatite ,HA)涂层与宿主骨之间有一定间隙的情况下新骨能长入间隙 ,形成骨键合 ,起到桥接作用 ,在临床上具有非常重要的作用。然而 ,多大的间隙为HA涂层最大桥接距离 ,各种实验数据相差很大。本实验在纯钛基底上用等离子喷涂及水蒸汽后处理法制得结晶度为 88% ,厚约 10 0 μm的HA涂层。选用狗的股骨为实验对象 ,纯钛和HA涂层为植入体 ,植入体与宿主骨之间的间隙为 2mm。组织形貌学显示 :12周后 ,HA涂层与宿主骨之间的间隙被新骨充满 ,涂层与骨之间形成直接的骨键合 ;而纯钛植入体与宿主骨之间的间隙为纤维组织充填。     

基于增材制造技术修复缺损颅骨的研究和应用

该文运用增材制造技术快速制备三维重建的缺损颅骨植入体,通过对骨植入体材料对比分析,选择多孔羟基磷灰石材料应用于颅骨植入手术中。运用Mimics 10.0软件对临床计算机断层扫描(CT)影像数据重建三维植人体模型,采用增材制造技术制备多孔羟基磷灰石颅骨植入体,与颅骨贴合度好,表面光滑平顺,而多孔羟基磷灰石能够引导和诱导骨的形成,大大提高其生物相容性。增材制造技术快速制备的特点促使个性化颅骨修补植入物成为可能,个性化医用三维模型用于植入手术降低手术风险,术后效果好,具有推广应用的前景。     

双侧股骨近端对称性及解剖形态的三维重建研究

目的建立正常成人双侧股骨近端的三维模型,分析双侧股骨近端形态并测量解剖形态的相关参数,研究双侧股骨近端的对称性及解剖形态。方法选取50例正常成人双侧股骨近端CT扫描数据,其中男性27例,女性23例;年龄20～65岁,平均年龄44.52岁。扫描参数:扫描层厚0.625 mm,扫描电压120 kV,扫描电流100 mA。扫描范围:自双侧股骨头上10 mm至小转子中点平面下50 mm。将双侧股骨近端CT薄层扫描数据利用Mimics 10.01软件进行三维重建,将左侧股骨与右侧股骨镜像模型相配准,对配准后模型进行三维测量,并测量左右股骨近端的形态参数,使用SPSS 16.0软件对测量结果进行统计分析。结果股骨近端形态和髓腔内部结构有明显的个体差异性,双侧股骨近端形态及内部结构具有高度对称性。股骨头直径为(45.71±4.08)mm,股骨头高度为(53.61±5.43)mm,偏心距为(39.91±5.07)mm,股骨颈中央直径为(36.71±3.75)mm,颈干角为(127.88±6.28)°,股骨颈长度(46.61±4.74)mm,小粗隆中点所在平面的髓腔内径为(26.21±4.59)mm,其中偏心距、颈干角与白种人形态参数相比,差异有显著统计学意义(P<0.01);提供了一种验证双侧股骨对称性的新方法。结论正常成人双侧股骨内外部形态存在一定的对称性,变异较小,为股骨形态的测量提供理论依据;三维重建更利于对股骨近端形态参数的测量;新配准方法的提出对于临床中股骨近端骨折的诊治具有重大意义。     

儿童股骨近端解剖钢板生物力学及三维有限元分析

背景：以往的三维有限元研究多集中在成人骨科生物力学方面。 目的：以三维有限元方法分析儿童股骨近端解剖钢板固定股骨转子下骨折的生物力学性能。 方法：从6具儿童尸体上取股骨12根,X射线排除骨病后分为2组,实验组采用儿童股骨近端解剖钢板固定,对照组采用重建钢板固定。分别进行生物力学实验,测试其轴向压缩、扭转刚度、弯曲刚度。选取1名健康男性儿童进行螺旋CT扫描技术,获得股骨近端图像数据,建立儿童股骨近端三维有限元模型,并进行三维有限元力学分析。 结果与结论：在轴向压缩刚度、扭转刚度上儿童股骨近端解剖钢板与重建钢板两者比较差异无显著性意义(P > 0.05);在抗弯曲刚度上,两者相比差异有显著性意义(P < 0.05)。结果显示儿童股骨近端解剖钢板的抗压能力、抗扭能力上与重建钢板相当,而在抗弯曲能力上强于重建钢板。生物力学三维有限元分析显示儿童股骨近端解剖型钢板的设计符合生物力学原理,具有较好的强度、刚度和稳定性,能够满足对儿童股骨近端骨折固定的需要。儿童股骨近端解剖型钢板对固定股骨转子下骨折具有良好的生物力学性能。     

基于激光快速成型技术正常步态下骨盆应力分布的三维光弹分析

背景：三维有限元技术是对应力真实情况的数字模拟,光弹技术可以真实显示测试模型的整体应力分布。 目的：使用激光快速成型技术制备骨盆光弹模型,以三维光弹法研究正常步态下髋臼区域的应力分布特征并与使用有限元法获得的数据进行比较。 方法：使用激光快速成型技术制备骨盆光弹模型,包括第5腰椎及双侧股骨近端。在股骨上施加体质量负荷,通过固定在髂骨翼前部髂前上棘髂后上棘及耻骨下支的钢丝施加负荷模拟4组肌群,假定股骨内收15°,支撑相4个子步态股骨从屈曲22°到后伸12°。应力冻结后,沿弓状线切片。在偏振光场中观察等差线及等倾线。 结果与结论：①应力集中点位于髂骨中部、髋臼后上、髂耻联合及骶髂关节部位,其中最大应力产生在髋臼后上部。②主应力从从臼顶后上部位向骶髂关节传递,同时部分向耻骨上支传递。随着股骨后伸的加大,臼顶至髂结节区域的应力逐步加大。③髋臼区域的应力主要来源于体质量负荷产生的头臼作用力,肌肉收缩力的作用有限。结果提示,采用三维光弹法可直观全场反映髋臼区域应力分布特征,与既往有限元实验产生的结果基本相符。     

Heterotypic interference between influenza viruses A/Aichi/2/68 and B/Massachusetts/1/71.

Virus particles produced by MDCK cells mixedly infected with 3 PFU/cell each of A/Aichi/2/68 (H3N2) (Aichi) and B/Massachusetts/1/71 (Mass) influenza viruses exclusively possessed haemagglutinin (HA) of Mass, although approximately one-fifth of the mixed yield had coding potential for Aichi serotype. Synthesis of major viral proteins of Aichi was markedly suppressed by co-infecting Mass. By increasing the multiplicity of co-infecting Aichi to 30 PFU/cell, interference became reciprocal. Aichi interfered with replication of Mass more severely than Mass did with replication of Aichi. All the major viral proteins of both Aichi and Mass were expressed within the infected cells.     

Recent H1N1 viruses (A/USSR/90/77, A/Fiji/15899/83, A/Firenze/13/83) replicate poorly in ferret bronchial epithelium

Summary Three recent wild-type H1N1 influenza virus isolates (A/USSR/90/77, A/Fiji/15899/83 and A/Firenze/13/83) replicated poorly in organ cultures of ferret bronchial tissue compared with the replication of an H3N2 wild-type virus (A/England/939/69). All four viruses replicated well in nasal turbinate tissue. Examination of one H1N1 virus (A/USSR/90/77)in vivo showed heavy infection in the upper respiratory tract of ferrets but little in the lower respiratory tract. These results raise the possibility that the mildness of human influenza arising from the H1N1 strains may be due to lack of capacity to attack the lower respiratory tract as well as the presence of antibody in previously exposed persons.With 1 Figure     

Pathogenicity of PMV-3/parakeet/Netherlands/449/75 for chickens

Infection of 1-day-old chicks with PMV-3/parakeet/Netherlands/449/75 (449) by intramuscular, intranasal or contact routes resulted in severe impairment of growth in all groups compared to uninfected control birds. In the group infected intramuscularly with 449 virus 16/22 birds died within 14 days of infection. No clinical signs were seen in 6-week-old chickens infected with 449 by intramuscular, intranasal or contact routes. One-day-old chicks infected with a large dose of NDV-B(1) and one-day-old chicks placed in contact with these birds also showed significant impairment of growth compared to uninfected controls.     

O2 Delivery and the Venous PO2-O2 Uptake Relationship in Pump-Perfused Canine Muscle

Under the conditions of both an increased red cell affinity for O(2) at a constant rate of O(2) delivery (arterial O(2) content x flow) and a decrease in the rate of O(2) delivery induced by hypoxic hypoxia at constant blood flow, we have obtained a linear relationship between the partial pressure of O(2) in the muscle venous effluent (P(v,)(O(2))) and O(2) uptake (.V(O(2))). The relationship is described by the equation .V(O(2)) = D(a) x P(v,)(O(2)) + .V(O(2)conv)) where D(a) is the apparent O(2) diffusion capacity and .V(O(2)conv)) is O(2) delivery-limited .V(O(2)), and D(a) x P(v,)(O(2)) represents the O(2) diffusion-limited .V(O(2)) .V(O(2)diff)). From these observations, we propose the hypothesis that .V(O(2)) consists of two additive values, .V(O(2)conv)) and .V(O(2)diff)). The mechanism underlying the reduction in .V(O(2)) that is induced by reducing O(2) delivery to markedly below the .V(O(2)conv)) value has only been investigated using a model based on the single compartment of diffusion-limited .V(O(2)), and has not been investigated in terms of this additive .V(O(2)) model. The single compartment analysis appears to overestimate the role of O(2) diffusion in limiting the reduction of .V(O(2)) that occurs in response to a decrease in O(2) diffusion capacity, as reflected by the .V(O(2))/P(v,)(O(2)) ratio. To gain better insight into the mechanism involved, we altered the rate of O(2) delivery by changing arterial P(O(2)) from normoxia (with inhalation of air) to hypoxia (by inhalation of 10-11 % O(2)) and blood flow (with high and low flow rates (n = 7 for both groups), and very low and ischaemic flow rates (n = 4 for both groups)) in pump-perfused dog gastrocnemius preparations during tetanic isometric contractions at 1 Hz. As rates of O(2) delivery were reduced from 23.2 to 10.9 ml min(-1) (100 g)(-1), significant decreases in P(v,)(O(2)) and .V(O(2)) were observed (P < 0.05). From the data of P(v,)(O(2)) and .V(O(2)) values within this range of O(2) delivery rates, we obtained the regression equation .V(O(2)) = 0.22 x P(v,)(O(2)) + 8.14 (r = 0.58). From the equation, the intercept of the .V(O(2))-axis was significantly different from zero (P < 0.05), in accordance with the observation that the .V(O(2)) /P(v,)(O(2)) ratio (ml min(-1) (100 g)(-1) Torr(-1)) increased from 0.54 to 1.35 (P < 0.05). However, at extremely low rates of O(2) delivery (5.6 and 7.3 ml min(-1) (100 g)(-1) the .V(O(2))/P(v,)(O(2)) ratio was 1.51 and 2.80 (P < 0.05), respectively. This indicates a break in the linear .V(O(2))-P(v,)(O(2)) relationship as the rate of O(2) delivery was reduced to below the .V(O(2)conv)) value of the .V(O(2))-axis intercept. These results suggest that the reduction in .V(O(2)) caused by extreme reductions in the rate of O(2) delivery is not attributable to a reduction in O(2) diffusion capacity, as expected from the .V(O(2))/P(v,)(O(2)) ratio, but to a reduction in the O(2) delivery-limited .V(O(2)) component, as evaluated by the .V(O(2))-axis intercept of the linear .V(O(2))-P(v,)(O(2)) relationship.     

A comparison of the biochemical properties of the human diaphorase (DIA3) isozymes determined by the common alleles DIA13, DIA23 and DIA33

(1) Various buffer systems for the starch gel electrophoresis of human diaphorase isozymes have been explored. Electrophoresis in a Tris/Borate system at pH 8.6 which includes 70 micron NADH in the gel and cathodal electrode buffers, provides good resolution of the six DIA3 phenotypes previously resolved by isoelectric focusing. (2) The variant genes DIA13, DIA23 and DIA33 occur with frequencies of about 0.76, 0.23 and 0.01 respectively in the English population. (3) The isozymes determined by the least common gene, DIA33, are markedly different from the isozymes determined by DIA13 and DIA23 in their relatively low heat stability, high affinity for Blue Sepharose and slow anodal electrophoretic mobility in buffer systems containing borate. The DIA3 1 and DIA3 2 isozymes are similar to one another in these characteristics.     

Associations Between G/A1229, A/G3944, T/C30875, C/T48200 and C/T65013 Genotypes and Haplotypes in the Vitamin D Receptor Gene, Ultraviolet Radiation and Susceptibility to Prostate Cancer

Ultraviolet radiation (UVR) may protect against prostate cancer via a mechanism involving vitamin D. Thus, the vitamin D receptor (VDR) gene is a susceptibility candidate, though published data are discrepant. We studied the association of prostate cancer risk with five VDR single nucleotide polymorphisms (SNPs): G/A¹²²⁹ (SNP 1), A/G³⁹⁴⁴ (SNP 2), T/C³⁰⁸⁷⁵ (SNP 3), C/T⁴⁸²⁰⁰ (SNP 4) and C/T⁶⁵⁰¹³ (SNP 5), in 430 cancer and 310 benign prostatic hypertrophy (BPH) patients. The SNP 2 GG genotype frequency was lower in cancer than BPH patients (odds ratio = 0.63, 95% CI = 0.41–0.98, p = 0.039). SNPs 1 and 2, and SNPs 4 and 5, were in linkage disequilibrium. Two copies of haplotypes comprising SNPs 1‐2, G‐G (odds ratio = 0.63, p = 0.039), SNPs 2‐3 G‐C (odds ratio = 0.45, p = 0.008) and SNPs 1‐2‐3 G‐G‐C (odds ratio = 0.44, p = 0.006), but not SNPs 1‐3, G‐C (odds ratio = 0.81, p = 0.34), were associated with reduced risk (reference, no copies of the haplotypes) . These associations were observed after stratification of subjects by extent of UVR exposure. These data show that SNP 2 GG genotype mediates prostate cancer risk, complementing studies reporting this allele is protective in malignant melanoma pathogenesis. They further suggest that published associations of risk with SNP 1 may result from linkage disequilibrium with SNP 2.