纳米化表面钛合金内植物的界面组织学和生物力学评价

背景:假体松动是造成人工关节置换失败和翻修的主要原因之一。材料表面处理能够促进假体和骨组织界面的骨整合,提高假体的稳定性。目的:研究纳米化表面钛合金(Ti6A14V)內植物在动物体内的骨整合情况。方法:基于严重塑性变形原理制备纳米化表面钛合金。在比格犬股骨髁间植入普通表面、羟基磷灰石表面和纳米化表面钛合金内植物,置入后3个月取材,处死前行影像学观察,处死后取带有内植物的股骨髁制作不脱钙骨组织磨片,行Van Gieson苦味酸一品红染色,观察内植物和骨组织界面组织学情况,并进行骨动力学参数计算。同时行推出实验,比较不同表面内植物和骨组织界面生物力学情况。结果与结论:影像学检查,见内植物和骨组织结合良好;界面组织学可见羟基磷灰石表面和纳米化表面钛合金与骨界面有大量成熟骨小梁直接结合,两者界面骨结合率相似(P>0.05),但都优于普通表面钛合金(P<0.01);推出实验显示羟基磷灰石表面和纳米化表面钛合金內植物和骨组织的结合力相似(P>0.05),但都优于普通表面钛合金(P<0.001)。提示严重塑性变形原理制备的纳米化表面钛合金和羟基磷灰石表面钛合金一样具有成骨诱导活性,能够促进骨整合,具有良好的临床应用前景。     

纳米化表面钛合金内植物的界面组织学和生物力学评价

背景：假体松动是造成人工关节置换失败和翻修的主要原因之一。材料表面处理能够促进假体和骨组织界面的骨整合,提高假体的稳定性。目的：研究纳米化表面钛合金（Ti6A14V）內植物在动物体内的骨整合情况。方法：基于严重塑性变形原理制备纳米化表面钛合金。在比格犬股骨髁间植入普通表面、羟基磷灰石表面和纳米化表面钛合金内植物,置入后3个月取材,处死前行影像学观察,处死后取带有内植物的股骨髁制作不脱钙骨组织磨片,行Van Gieson苦味酸一品红染色,观察内植物和骨组织界面组织学情况,并进行骨动力学参数计算。同时行推出实验,比较不同表面内植物和骨组织界面生物力学情况。结果与结论：影像学检查,见内植物和骨组织结合良好;界面组织学可见羟基磷灰石表面和纳米化表面钛合金与骨界面有大量成熟骨小梁直接结合,两者界面骨结合率相似（P〉0.05）,但都优于普通表面钛合金（P〈0.01）;推出实验显示羟基磷灰石表面和纳米化表面钛合金內植物和骨组织的结合力相似（P〉0.05）,但都优于普通表面钛合金（P〈0.001）。提示严重塑性变形原理制备的纳米化表面钛合金和羟基磷灰石表面钛合金一样具有成骨诱导活性,能够促进骨整合,具有良好的临床应用前景。     

羟磷灰石涂层钛合金植入材料的理化参数、生物相容性及其力学特征

背景羟磷灰石涂层人工关节具有骨长入生物固定作用而能与宿主床骨紧密联结,从而解决人工关节下沉问题.目前临床上最常用的羟基磷灰石(HA)涂层材料主要使用的是等离子喷涂法所制.这种制备方法因为高温,使HA不可避免地产生晶相结构改变,从而使HA的生物活性大为下降,直接影响假体与骨之间的结合.目的通过涂覆工艺研制出一种新的含羟磷灰石玻璃涂层钛合金多孔涂复材料.本实验对该材料进行了理化参数、生物相容性及其力学特征的测定,为该材料在临床的应用提供实验依据.设计随机分组,自身对照实验研究.地点和对象研究在上海市伤骨科研究所完成.48个HA表面涂层及非涂层钛合金材料由轻工业部玻璃塘瓷工业科学研究所制备.干预①测定材料的最佳烧结温度、机械强度,观察材料表面的多孔结构.②取24只新西兰种家兔,在两侧股骨外髁上共植入48个HA表面涂层及非涂层钛合金材料,分别于术后1,2,3,6及12周处死取材.测定骨-HA界面最大剪切强度并作组织学观察.主要观察指标①材料最佳烧结温度、机械强度.②材料表面多孔结构、切片组织学观察.③骨-HA界面的最大剪切强度.结果测出材料的最佳烧结温度为800℃,抗剪强度为18.5 MPa,抗压强度为170 MPa,孔隙率10%～15%,孔径30～70μm.HA涂层钛合金组能与宿主骨紧贴,新骨能迅速长入材料的裂隙和被降解的封闭小孔内,而非涂层材料能使新生骨组织死亡并为结缔组织取代.在术后任一时间段涂层材料骨-HA界面最大剪切强度均明显高于非涂层组.(术后3周均差=0.86,t=15.61,P＜0.01;术后6周均差=1.72,t=18.19,P＜0.01;术后12周均差=4.42,t=12.84,P＜0.01)结论这种新材料能作为人工骨或人工关节材料应用于临床.     

Incorporation of different antibiotics into carbonated hydroxyapatite coatings on titanium implants, release and antibiotic efficacy.

Carbonated hydroxyapatite (CHA) coatings were applied onto titanium implants by using a biomimetic precipitation method. Different antibiotics were incorporated into the CHA coatings and their release and efficacy against bacteria growth were studied in vitro. The following antibiotics were used within this study: cephalothin, carbenicillin, amoxicillin, cefamandol, tobramycin, gentamicin and vancomycin. Increased concentrations of antibiotics in the coating solution led to a higher quantity of antibiotic incorporated into the CHA coating. Some antibiotics were better incorporated than others depending on their chemical structure. Antibiotics, containing carboxylic groups such as cephalothin, carbenicillin and cefamandol, were better incorporated than antibiotics lacking these groups. A bacterial inhibition test on Staphylococcus aureus bacteria showed inhibition of growth for all antibiotics that were released from the CHA coating. A release test was conducted in phosphate buffer saline PBS at pH 7.4 and 37 degrees C and showed that antibiotics containing carboxylic groups like cephalothin were slower released from the CHA coating than others. These results suggest that certain antibiotics are able to bind/chelate with calcium, resulting in a better incorporation into the CHA coating and a slower release. Antibiotics incorporated in CHA coatings on titanium implants might be used to prevent post-surgical infections and to promote bone-bonding of orthopedic devices.     

Demineralized bone matrix and human cancellous bone enhance fixation of porous‐coated titanium implants in sheep

Allogenic bone graft has been considered the gold standard in connection with bone graft material in revision joint arthroplasty. However, the lack of osteogenic potential and the risk of disease transmission are clinical challenges. The use of osteoinductive materials, such as demineralized bone matrix (DBM), alone or in combination with allograft or commercially available human cancellous bone (CB), may replace allografts, as they have the capability of inducing new bone and improving implant fixation through enhancing bone ongrowth. The purpose of this study was to investigate the effect of DBM alone, DBM with CB, or allograft on the fixation of porous‐coated titanium implants. DBM100 and CB produced from human tissue were included. Both materials are commercially available. DBM granules are placed in pure DBM and do not contain any other carrier. Titanium alloy implants, 10 mm long × 10 mm diameter, were inserted bilaterally into the femoral condyles of eight skeletally mature sheep. Thus, four implants with a concentric gap of 2 mm were implanted in each sheep. The gap was filled with: (a) DBM; (b) DBM:CB at a ratio of 1:3; (c) DBM:allograft at a ratio of 1:3; or (d) allograft (gold standard), respectively. A standardized surgical procedure was used. At sacrifice 6 weeks after implantation, both distal femurs were harvested. The implant fixation was evaluated by mechanical push‐out testing to test shear mechanical properties between implant and the host bone and by histomorphometry. Non‐parametric tests were applied; p < 0.05 was considered significant. Mechanical fixation showed that the strengths among the DBM/CB, DBM/allograft and allograft groups were not statistically different. The strength of the DBM group was 0.01 MPa, which was statistical significantly lower than the other three groups (p < 0.05). Histomorphometry results showed that the bone ongrowth in the DBM group was statistically significantly lower than the other three groups, while the volume fraction of new bone showed no significant difference among all the groups. Our data revealed that adding DBM to CB or to allograft resulted in comparable mechanical properties relative to the gold standard, allograft. We found inferior early effects of DBM alone on the fixation of porous‐coated titanium implant in this animal model, while the long‐term effects have to be investigated. The combination of DBM with CB, which can be used off the shelf, may represent an alternative to allograft. A cost–benefit analysis is necessary before application in clinical trial. Copyright © 2013 John Wiley & Sons, Ltd.     

原位形成骨骼矿物相材料碳酸化磷灰石的骨界面组织学特点

目的:通过观察碳酸化磷灰石与骨界面间形态学特征及其成骨和降解情况,探讨原位形成骨骼矿物相材料碳酸化磷灰石的组织学特点。方法:实验于2001-03/11在解放军总医院骨科研究所完成。选用成年新西兰兔30只,将两侧股骨远端制作直径5mm,深10mm的缺损模型,随机选一侧植入碳酸化磷灰石为实验组,另一侧植入聚甲基丙烯酸甲酯为对照组。于术后1,4,8,12和16周时分批麻醉处死动物,每批6只。对植入材料与骨界面之间形态及降解的情况进行以下观察。①大体观察。②组织学检测。③体视显微镜观察。④荧光染色观察。⑤钼靶软X射线观察。结果:术后大体观察、组织学观察、体视显微镜观察、荧光染色观察和钼靶软X射线观察显示碳酸化磷灰石术后在1周时固化填充良好,与骨结合紧密,4周时界面出现成骨,8周时开始降解,16周时大部分碳酸化磷灰石已经降解,有大量新骨形成。聚甲基丙烯酸甲酯组界面间始终没有成骨现象,1周时聚甲基丙烯酸甲酯固化填充良好,与骨结合紧密,8周时界面间开始形成纤维结缔组织,16周时界面间形成一层厚的致密纤维结缔组织。结论:碳酸化磷灰石是生物相容性非常好的生物活性材料,植入体内后能够与骨直接结合,界面间不形成纤维结缔组织并持续有破骨和成骨活动存在,随时间推移可以逐步降解,但是确定完全降解的时间尚需更长时间的观察和验证。     

Glycerol-l-lactide coating polymer leads to delay in bone ingrowth in hydroxyapatite implants.

Glycerol-l-lactide as coating polymer for the delivery of basic fibroblast growth factor (bFGF) from hydroxyapatite (HA) ceramic implants was shown to lead to significant delay in bone ingrowth into the implants compared to implants without the coating polymer. The purpose of this work was to study bone ingrowth in HA ceramic implants with and without the coating polymer but without growth factors to enable differentiation between a locking effect of the pores by the polymer and the fact of inactivation of the growth factors by the polymer, which could both be possible for the delay. A defect was created in the subchondral region of both femurs in 24 miniature-pigs and was either filled by the HA implants with or without the coating polymer. Histomorphometry showed a significant delay in bone ingrowth in the polymer coated implants both after 6 and 12 weeks. Detailed histology revealed that the HA pores were completely "locked" by the polymer leading to complete loss of the osteoconductive properties of the HA. Also electron microscopy showed filling of the HA pores by the polymer. Therefore, it can be concluded that glycerol-l-lactide should not be used to coat HA ceramic implants due to significant delay in bone ingrowth.     

Management of cranial and craniofacial bone defects with prefabricated individual titanium implants: follow-up and evaluation of 166 patients with 169 titanium implants from 1994 to 2000

Objective The TICC (Tomography, Image processing, CAD, CAM) processing chain developed at the Ruhr-University Bochum in Germany has already been established since several years for the reconstruction of large pre-existing posttraumatic skull defects with individual prefabricated implants made of pure titanium. So far, more than 500 titanium implants have been inserted with great success at more than 60 clinical centres worldwide. The aim of our study was to evaluate all implants inserted between 1994 and 2000. Materials and Methods The study describes the clinical experience with 166 patients receiving 169 skull implants between 1994 and 2000. All 169 implants were measured and categorized in the CAD system in terms of size and anatomical localization. The surgical and radiological reports of the patients were evaluated. Sixty patients operated at the university hospital in Bochum and nearby were clinically reviewed describing scars, position of the implants and cosmetic results. Questionnaires of 131 patients were analyzed regarding the postoperative quality of life distinctly. Results The study shows constantly good to excellent results intraoperatively as well as postoperatively regarding complications, fit of the implants and the clinical follow-up. In particular the enquiry of the patients shows that titanium skull implants improve quality of life. Conclusion High precision and easy handling as well as a low complication rate and the high contentedness of the patients make the individual titanium skull implants valuable for cranioplasty, especially in complicated applications with very large defects, multiple previous operations and additional irradiations. Even in these difficult cases predictable results are possible.     

A procedure for the visualization of bone with hydroxyl-apatite coated implants

A procedure for the histological visualization of the interface between implants coated with hydroxyl-apatite (HA) and bone, and the reaction of bones to the implants, has been developed. Thick sections of bones with HA-coated stainless-steel implants, were investigated with the implant still in situ with routine and (confocal) fluorescence microscopy. The prosthesis-HA-bone interface, bone cells, necrotic and vascularised bone, bone-ingrowth and bone remodelling could be visualised. After removal of the implant from the sections alternative sections were further processed for routine light microscopy, microradiography and detailed fluorescence studies. It appeared that the HA coating was still intact and the integrity of the HA-bone bond was very well preserved. The HA coating layer had the same appearance as after the first inspection with surface microscopy. However, more details were visible. Prosthesis-related and time-related changes in the appearance of the HA layer were detected. The advantage of the procedure is that observations can be made of bone reactions with the prosthesis still in situ, without previous embedding in plastics, and laborous sectioning and/or grinding procedures. Thereafter, sections can be processed for different histological techniques, e.g. immunocytochemistry, routine histology, microradiography, fluorescence microscopy, apparently without imparing the HA coating layer.     

用磁控溅射技术制备钛合金表面羟基磷灰石生物涂层

背景:射频磁控溅射是在陶瓷(金属)基体上制备金属(陶瓷)涂层的成熟技术,具有基体温升低、沉积速度快、涂层成分均匀、性能稳定、结合强度高等优点。目的:探讨磁控溅射法制备的羟基磷灰石生物涂层组织结构以及涂层与基体的界面结合性能。设计:单一样本观察。单位:江苏大学材料科学与工程学院。材料:试样基体为30mm×30mm×3mmTi-6Al-4V板材;JGP500超高真空多靶磁控溅射仪。方法:实验于2003-12/2004-09在江苏大学材料试验中心完成。利用射频磁控溅射技术在Ti-6Al-4V基体表面制备羟基磷灰石生物涂层,利用扫描电镜观察生物涂层表面形貌和断面形貌,利用X射线衍射仪分析涂层的相结构,利用能量分散谱仪分析涂层的Ca/P比,采用环氧树脂E-7对接法测定涂层与基体的界面结合强度。主要观察指标:①羟基磷灰石生物涂层微观形貌。②羟基磷灰石生物涂层组成及后处理影响。③羟基磷灰石生物涂层与基体的界面结合状态及结合强度。结果:①羟基磷灰石生物涂层表面扫描电镜观察,涂层表面较为粗糙,呈凹凸不平状,呈现出较多的孔隙和网状结构,其孔隙面积约占30%～40%。②溅射羟基磷灰石生物涂层的Ca/P比为1.7。后处理生物涂层主要成分为晶化程度高的羟基磷灰石,不存在其他钙磷杂质相。③羟基磷灰石涂层与基体的界面结合强度为51.2MPa。结论:射频磁控溅射技术制备的羟基磷灰石生物涂层,表面形貌良好,涂层与基体的界面结合强度较高。     

用磁控溅射技术制备钛合金表面羟基磷灰石生物涂层

背景：射频磁控溅射是在陶瓷（金属）基体上制备金属（陶瓷）涂层的成熟技术，具有基体温升低、沉积速度快、涂层成分均匀、性能稳定、结合强度高等优点。 目的：探讨磁控溅射法制备的羟基磷灰石生物涂层组织结构以及涂层与基体的界面结合性能。 设计：单一样本观察。 单位：江苏大学材料科学与工程学院。 材料：试样基体为30mm&;#215;30mm&;#215;3mm Ti-6A1．4V板材；JGP500超高真空多靶磁控溅射仪。 方法：实验于2003-12／2004—09在江苏大学材料试验中心完成。利用射频磁控溅射技术在Ti-6Al-4V基体表面制备羟基磷灰石生物涂层，利用扫描电镜观察生物涂层表面形貌和断面形貌，利用X射线衍射仪分析涂层的相结构，利用能量分散谱仪分析涂层的Ca／P比，采用环氧树脂E-7对接法测定涂层与基体的界面结合强度。 主要观察指标：①羟基磷灰石生物涂层微观形貌。②羟基磷灰石生物涂层组成及后处理影响。③羟基磷灰石生物涂层与基体的界面结合状态及结合强度。 结果：①羟基磷灰石生物涂层表面扫描电镜观察，涂层表面较为粗糙，呈凹凸不平状，呈现出较多的孔隙和网状结构，其孔隙面积约占30％-40％。②溅射羟基磷灰石生物涂层的Ca／P比为1．7。后处理生物涂层主要成分为晶化程度高的羟基磷灰石，不存在其他钙磷杂质相。③羟基磷灰石涂层与基体的界面结合强度为51．2MPa。 结论：射频磁控溅射技术制备的羟基磷灰石生物涂层，表面形貌良好，涂层与基体的界面结合强度较高。     

非血管化髂骨移植同期种植实验

AIM:To investigate the osseointegration process of titanium implant and non vascularized iliac bone grafts.METHODS:12 mongrel were divided into 4 groups randomly.Bone grafts were resected from iliac crest and then transplanted to the other side.Animals were skilled in different time after surgery,X ray pictures were taken,then histological observation were done.RESULTS:At 3rd week,bone grafts dissolved,resorbed or necrosis partly;At 6th week,new bone began to regenerated;At 9th week,the amount of new bone increased;At 12nd week,bone interface around implant formed,without soft tissue interrupt.CONCLUSION:Osseointegration can formed between non vascularized iliac bone grafts and titanium implant.     

个体化预制医用树脂和羟基磷灰石复合材料修复颅骨缺损

目的:个体化预制医用树脂和羟基磷灰石复合人工骨材料应用于不同部位颅骨缺损患者的颅骨修复和重建。方法:纳入2003-01/2004-06上海第二医科大学附属宝钢医院32例脑损伤开颅术后患者,利用计算机三维重建和计算机数控成型技术,将个体化设计成型的医用树脂和羟基磷灰石复合人工骨材料植入脑外伤后颅骨缺损患者的颅骨缺损部位进行重建和修复,并随访6个月,参与者知情同意。结果:32例患者均完成6个月随访,随访率100%。术后6个月随访时颅骨缺损修复后外形效果满意。CT复查显示修复材料位置良好,形态正常,患者及家属对手术效果非常满意,所有病例都没有发生排异现象。结论:医用树脂和羟基磷灰石复合人工骨材料个体化修复颅骨缺损,术后成型效果较好,术后未发生排异反应。     

Experiment of non-vascularized iliac bone grafts with the simultaneous placement of titanium implants

AIM:To investigate the osseointegration process of titanium implant and non-vascularized iliac bone grafts.METHODS:12 mongrel were divided into 4 groups randomly.Bone grafts were resected from iliac crest and then transplanted to the other side.Animals were skilled in different time after surgery,X-ray pictures were taken,then histological observation were done.RESULTS:At 3rd week,bone grafts dissolved,resorbed or necrosis partly;At 6th week,new bone began to regenerated;At 9th week,the amount of new bone increased;At 12nd week,bone interface around implant formed,without soft tissue interrupt.CONCLUSION:Osseointegration can formed between non-vascularized iliac bone grafts and titanium implant.     

改性羟基磷灰石骨修复纳米复合材料的制备及生物学评价

目的:制备羟基磷灰石/聚乳酸聚乙醇酸骨修复材料,并对其进行生物学评价。方法:实验于2006-06/2007-02在中科院长春应用化学研究所完成材料制备,在吉林大学基础医学院实验动物中心完成动物实验。将低聚乳酸的羧基与羟基磷灰石表面的钙原子用化学键连接,得到表面接枝聚左旋乳酸的羟基磷灰石,将其与聚乳酸聚乙醇酸共混,得到复合材料PLLA-g-HA/PLGA。溶于氯仿后铺膜(厚0.2mm),用DMEM培养液浸泡材料膜制备浸提液。首先,进行材料生物安全性实验:①细胞毒性实验:将浸提液与培养液混合,接种兔成骨细胞,培养24h,MTT法检测细胞增殖,计算细胞增殖率和细胞毒性级(细胞毒性级0或1级为合格)。②全身毒性实验:小鼠以50mL/kg的剂量静脉注射浸提液,观察72h内小鼠中毒症状。③皮肤刺激实验:兔脊柱两侧皮内注射材料浸提液,观察72h内皮肤有无异常反应。④热原实验:自兔耳缘静脉注入浸提液(10mL/kg)。注射后每0.5h测肛温1次,共6次,以6次中最高的1次减去正常体温,计为升高度数。其次,对复合材料进行细胞黏附性检测:将复合材料制成1%氯仿溶液,涂于硅化的盖玻片上,置于6孔板,每孔接种1×105个成骨细胞,培养3d,在2,24,72h行FITC荧光染色,数码摄像系统拍摄细胞荧光照片。结果:制备了新型PLLA-g-HA/PLGA复合材料。①生物安全性实验结果:MTT实验检测复合材料细胞增殖率为94.8%,细胞毒性级为1级;全身毒性实验中动物无死亡、惊厥、瘫痪、呼吸抑制、腹泻和体质量下降等不良反应;热原实验中兔体温最大的变化值是0.25℃(国家标准为<0.6℃);皮肤刺激实验中未见任何刺激反应,无红斑、焦痂、水肿表现。②细胞黏附性实验结果:细胞接种后2h可见少量细胞开始贴壁;24h时可见贴壁细胞明显增多,并呈聚集生长;培养3d后可见细胞逐渐融合,细胞状态良好。结论:新型PLLA-g-HA/PLGA复合材料符合生物材料细胞毒性要求,按毒性剂量分级属无毒级,无致热原性、对皮肤无刺激作用,具有良好的生物相容性和细胞黏附性。     

超声辅助微弧氧化钛合金表面制备含镧涂层的生物相容性评价

背景:稀土元素具有一定的生物效应,也有广谱抗菌、抗炎和抗病毒的能力,能提高涂层结合强度作用.目的:在种植体涂层中引入稀土镧,对引入稀土元素镧的钛基超声辅助微弧氧化涂层的生物相容性进行评价.方法:利用超声辅助微弧氧化在β型钛合金表面制备含镧生物涂层,并植入家兔股骨内.以钛合金基体和未加镧生物涂层作对照.采用光镜观察新骨形成,通过扫描电镜观察种植体与骨的结合情况和拔出种植体后其表面骨残留,并对骨接触率进行数据统计.结果与结论:实验组种植体周围新骨形成良好,未见到纤维形成和破骨细胞;扫描电镜观察及骨接触率以实验组最好,钛合金组最差.结果说明超声辅助微弧氧化制备的含镧生物涂层具有与新骨良好结合的能力,显示出较好的生物相容性.     

Histological and ultrastructural observations at the interface of expanded polytetrafluorethylene anterior cruciate ligament implants.

Anterior cruciate ligament (ACL) grafts made from expanded polytetrafluorethylene (ePTFE) were examined after failure (n = 7; 3 instabilities, 2 partial ruptures, and 2 complete ruptures) to provide information about secondary fixation mechanisms via ingrowth of the different tissues. The ultrastructural evaluation clearly evidenced the existence of two main interface areas of ePTFE ACL-replacement: First, in areas without a dense cellular infiltrate there was interdigitating collagen producing a dense ePTFE-collagen network. Additionally, in a few areas of the graft/bone-tunnel interface a fibrous cartilage or bone regenerate could be demonstrated to be in contact with the prosthesis. Second, there was a dense infiltration of macrophages and multinuclear giant cells, partially containing birefringent material of implant origin, with and without a neosynovia-like reaction product, indicating a disturbance of tissue integration of the prosthesis. In areas of inflammation there was no bone development and only few collagen interdigitation with the graft material. This study provides further knowledge about mechanisms of secondary graft fixation due to tissue ingrowth. The interdigitation of collagen fibers and ePTFE filaments provides interfaces which should be at least partially resistant against load.     

Prospective evaluation of double RBC collection using three different apheresis systems.

BACKGROUND: Automated component collection systems offer the possibility of increasing blood supply and improving transfusion safety. DESIGN: 30 blood donors were randomly assigned to double RBC collection with either the Baxter Alyx (AX), the Haemonetics MCS Plus (MCS+), or the Gambro Trima Accel (TA). Procedures were prospectively evaluated focussing on yield, time, efficiency, citrate donor load, and in vitro quality. RESULTS: All units showed sufficient in vitro quality throughout 42 days of storage and complied with international requirements. Donor reactions were limited to mild citrate reactions. AX was the fastest and most efficient system* * (* *p approximately 0.001) attaining the highest yield* * from similar amounts of whole blood. The drawbacks were a higher RBC loss* (*p < 0.05) and accelerated citrate infusion* *. Due to lower collection rates* * * (* * *p < 0.001), MCS+ was slower than TA* * * but compensated with lower citrate load * * *. CONCLUSION: Double RBC apheresis was performed safely and efficiently with all three instruments. AX had advantages for most parameters evaluated.     

Histological investigation of the tissue response to hydroxyapatite used as an implant material in periodontal treatment

Patients with severe periodontitis and who had one or more teeth with infrabony pockets were treated by periodontal surgery with implantation of hydroxyapatite particles into the bone defects at the time of surgery. Subsequently, in three patients it was found necessary to extract a tooth for reasons not related to the previous periodontal treatment. Specimens that included the local soft tissues and crestal bone attached to the teeth were obtained at 22, 40 and 80 weeks after placement of the implant. They were decalcified and stained with haematoxylin and eosin and examined under light microscopy. The healing response was found to vary between specimens, and between sites within the same specimen. The early stage of healing showed the implant particles surrounded by collagen. Subsequently, varying degrees of resorption of the periphery of the particles was seen, and at some sites bone deposition was observed. These different healing responses were found to be progressing concurrently at sites in close proximity. Further work is needed to confirm the histological findings described in the paper.     

Effects of molecular weight and surface functionalization on surface composition and cell adhesion to Hyaluronan coated titanium.

This paper describes the effect of surface functionalization on surface composition and cell adhesion to titanium samples by high and low molecular weight Hyaluronan (HA). HA was covalently linked to aminated Ti surfaces obtained by two different surface functionalization techniques, that is polyethyleneimine (PEI) adsorption and deposition from allylamine plasma. The two approaches yield very different surface densities of available amino groups, affecting this way the number and frequency of surface-HA bonds and the configurational freedom of the latter. Results of cell adhesion test are dependent on the surface functionalization approach adopted, low molecular weight HA coupled to PEI functionalized Ti does not yield the same degree of resistance to cell adhesion found on other samples. These results indicate that the details of the surface functionalization step are crucial for surface engineering of implant devices by biological molecules.