Chondrocyte-seeded hydroxyapatite for repair of large articular cartilage defects. A pilot study in the goat

The aim of this study was to evaluate the potential for restoration of a large cartilage defect in the goat knee with hydroxyapatite (HA) loaded with chondrocytes. Isolated chondrocytes were suspended in fibrin glue, seeded on top of the HA, and then the composite graft was implanted in the defect. After transplantation, cell behaviour, newly synthesised matrix and the HA–glue interface were assessed histologically after 2, 4, 12, 26 and 52 weeks. Special attention was paid to the incorporation process of HA in the subchondral bone and interactions between this biomaterial and the fibrin-glue–chondrocyte suspension.

Chondrocytes in the glue proved to survive the transplantation procedure and produced new metachromatically stained matrix two weeks after implantation. The glue–cell suspension had penetrated the superficial porous structure of the HA. Four weeks after surgery, islands of hyaline-like cartilage were observed at the HA–glue interface. A layer of fibrous tissue was formed surrounding the HA graft, resulting in a relatively instable fixation of the HA in the defect. This instability of the graft in the defect, possibly together with early weight bearing, resulted in a gradual loss of the newly formed hyaline cartilage-like repair tissue. Progressive resorption of the HA occurred without any sign of active bone remodelling from the host site. One year after surgery part of the defect which extended down to the cancellous bone had been predominantly restored with newly formed lamellar bone. Only small HA remnants were still present at the bottom of the original defect. Resurfacing of the joint had occurred with fibrocartilaginous repair tissue.

The absence of adequate fixation capacity of the HA near the joint space resulted in a relative instability of the graft with progressive resorption. Therefore, HA is not a suitable biomaterial to facilitate the repair of large articular cartilage defects.     

Disaggregation of bone into crystals

Summary The sizes, shapes, and organizational states of the crystals in bone are studied by systematic disaggregation of the mineral phase. This is achieved by oxidizing the organic phase with sodium hypochlorite, dispersing the resultant particles by sonication, and separating the crystal aggregates from the crystal monomers by gravity setting in ethanol. Six different bones are compared. Bones in which crystals are intimately associated with the collagen fibrils mostly disaggregate into crystal monomers. In dense bones, where the crystals are mostly located between fibrils, they tend to persist as “fused” aggregates. All the crystals are tabular or plate-shaped. In bones in which the majority of crystals are associated with the collagen fibrils, just less than 90% of the crystals are shorter than about 450 ? in length. Their widths are on the average about 250 ?, almost an order of magnitude larger than the diameters of individual gap regions within the collagen fibril. The notion that one crystal is located in one gap region is therefore untenable and a reevaluation of the relations between collagen and mineral in bone is necessary.     

羟基磷灰石涂层人工股骨柄的临床应用

自１９８９年１２月～１９９３年１１月，共收治各类髋关节病１４例（１５髋），均行ＦＵＲＬＯＮＧ羟基磷灰石（ＨＡ）涂层人工髋关节置换术。术后平均随访３２个月，髋关节功能按Ｈａｒｉｓ评分结果为平均９５分。无患肢疼痛和其它不适症状，亦无术后并发症发生。Ｘ线结果显示，股骨侧假体无松动、下沉表现，周围未见明显透亮线。术后３个月假体表面出现增生性骨反应，并在术后３～４年内逐渐增加。无明显骨萎缩表现。结合实验及临床研究结果，证明此种髋假体应用的短期疗效令人满意，其长期疗效尚有待进一步观察。     

PMMA/HA-GF医用复合材料制备及性能测试

本文主要研究了无机玻璃纤维增强聚甲基丙烯酸甲酯(PMMA)/羟基磷灰石(HA)复合材料的制备及相关的性能测试,证明此复合材料性能稳定、物理机械强度高以及工艺简单,有良好的应用前景。     

Calcium environment in bone mineral determined by EXAFS spectroscopy

Summary Extended X-ray absorption fine structure (EXAFS) spectra were recorded, above the Ca K edge, from powdered mouse femurs. Spectra were interpreted on the basis of a model developed previously to explain the features of the EXAFS spectrum of fully crystalline hydroxyapatite. Eight shells of atoms surrounding Ca out of 0.57 nm were required to explain the appearance of the EXAFS spectrum of bone. Shell radii and Debye-Waller factors were systematically varied to obtain the best fit between observed and theoretical spectra, calculated using exact spherical wave theory. The results were closely similar to those obtained previously from the interpretation of EXAFS spectra from poorly crystalline hydroxyapatite prepared by maturation of amorphous calcium phosphate. However, there appears to be slightly more disorder in bone mineral, perhaps as a result of its accommodating carbonate ions     

Bone Replacement Materials in Hand Surgery

Abstract Background: In recent years, biomaterials are being found and frequently utilized in bone defects. They have also gained significant precedence in hand surgery. Objectives: The respective requirements for such replacement material will be cited and acknowledged in this article. The individual material groups will also be referred to in this review. An introduction to some of the customary bone replacement materials will be cited and concluded with a corresponding recommendation. Conclusion: The implantation of autologous cancellous bone is still regarded today as the “gold standard”. Nevertheless, the usage of bone replacement material can be an enormous advantage in certain indications. The original article can be found online at There was an error in the author’s affiliation and the address for correspondence was incomplete. Please note the correct institution and complete address: Department of Orthopedics and Traumatology, Hand-, Foot- and Reconstructive Surgery, Kreiskrankenhaus Gummersbach GmbH, Germany. Alexander von Friesen, MD Department of Orthopedics and Traumatology, Hand-, Foot- and Reconstructive Surgery Kreiskrankenhaus Gummersbach GmbH Wilhelm-Breckow-Allee 20 51643 Gummersbach Germany Phone (+49/2261) 171-575, Fax -449 e-mail: Friesen@kkh-gummersbach.de     

羟磷灰石加阿霉素瘤内注射治疗小鼠肝癌的实验研究

作者通过动物实验研究了羟磷灰石(HA)的抑癌效果及其机理。将80只移植有H_(22)肝癌的BALB/c小鼠分为4组:Ⅰ组HA加阿霉素(ADM)瘤内注射;Ⅱ组HA瘤内注射;Ⅲ组ADM瘤内注射;Ⅳ组未给药。结果Ⅰ～Ⅲ组的肿瘤生长抑制率分别为65.9％、41.9％及51.1％。Ⅰ～Ⅳ组的生存时间分别为32、22、26及18天。作者认为HA抑癌作用的机理可能是:①直接界面作用;②诱导组织纤维化;③免疫激活作用;④药物载体和缓释作用。结果显示HA加ADM瘤内注射可能成为一种治疗恶性肿瘤的新方法。     

The effect of surface chemistry modification of titanium alloy on signalling pathways in human osteoblasts

Establishing and maintaining mature bone at the bone–device interface is critical to the long-term success of prosthesis. Poor cell adhesion to orthopaedic and dental implants results in implant failure. Considerable effort has been devoted to alter the surface characteristics of these biomaterials in order to improve the initial interlocking of the device and skeleton. We investigated the effect of surface chemistry modification of titanium alloy (Ti–6Al–4V) with zinc, magnesium or alkoxide-derived hydroxy carbonate apatite (CHAP) on the regulation of key intracellular signalling proteins in human bone-derived cells (HBDC) cultured on these modified Ti–6Al–4V surfaces. Western blotting demonstrated that modifying Ti–6Al–4V with CHAP or Mg results in modulation of key intracellular signalling proteins. We showed an enhanced activation of Shc, a common point of integration between integrins and the Ras/Mapkinase pathway. Mapkinase pathway was also upregulated, suggesting its role in mediating osteoblastic cell interactions with biomaterials. The signalling pathway involving c-fos (member of the activated protein-1) was also shown to be upregulated in osteoblasts cultured on the Mg and CHAP modified Ti–6Al–4V. Thus surface modification with CHAP or Mg may contribute to successful osteoblast function and differentiation at the skeletal tissue–device interface.     

C/C复合材料表面等离子喷涂HA涂层在SBF中的试验

目的 探讨不同模拟体液对HA涂层体外生物学行为的影响。方法采用等离子体喷涂法,在碳／碳复合材料表面制备HA涂层,并对涂层进行了热处理。利用X射线衍射仪(X-ray diffraction)、扫描电子显微镜(Scanning electron microscopy)等检测手段,分析该涂层的物相和形貌,观察HA涂层在模拟体液中的影响。结果XRD检测结果表明,在模拟体液浸泡过程中,涂层的主要组成相的相对含量和结晶度不断发生变化。由SEM分析结果可知,在浸泡过程中,内送粉方式下制得的HA涂层的表面沉积物呈现近似网状的结构。同时,在Ringer溶液中,可以观察到HA涂层溶解痕迹。结论通过适当的热处理可以恢复HA的结构完整性,同时提高涂层的结晶度。     

电化学共沉积制备有机高聚物/钙磷复合陶瓷膜层--Ⅱ XPS、SIMS表征及力学性能研究

通过电化学共沉积方法制备具有生物活性的有机高聚物／钙磷陶瓷复合膜层。用XPS、SIMS等对复合膜层的化学组分进行表征，证明少量有机高聚物可能在分子层次上掺杂形成有机高聚物／羟基磷灰石复合膜层。对电沉积HAP陶瓷膜层进行微刮痕实验表明，陶瓷膜层与金属基体的结合力得到显著改善。