Abstract To investigate the ectopic new bone formation following implantation of bovine hydroxyapatite Bio-oss together with free periosteum, 12 chabb: ch rabbits were selected. In 10 rabbits, Bio-oss block together with free periosteum was implanted in the gastrocnemius muscle of one leg randomly, and Bio-oss block alone was implanted in the same muscle of the other leg. In the other 2 rabbits, the periosteum was implanted into the gastrocnemius musle of both legs. Histologic examination and quantitative analysis of newbone formation were performed at 3 and 6 weeks postoperatively. The results showed that in the legs implanted bovine hydroxyapatite Bio-oss together with freeperiosteum, new bone formation began at 5th day after implantation. The area ofnew bone composed of 19.0% of the specimens at 3 weeks postoperatively. No boneformation through out the experimental period in Bio-oss block alone implantedlegs and also periosteum implanted legs. We concluded that bovine hydroxyapatite Bio-oss has a good capacity of osteoconduction. New bone can be formed after the implantation of hydroxyapatite combined with free periosteum.
Abstract To restore the bone defect after curettage of bone cyst, hydroxyapatite bioactive microcrystal glass (HBG) was used. From 1990 to 1995, HBG was applied in 17 cases. The bone involved were humerus, femur, tibia and fibula. Among them, 6 were complicated with pathological fracture. After eradication of the focus, the cyst was filled in ZnCl2 powder and irrigated with saline, then particles or segments of HBG were implanted into the cavity. The fracture were fixed with Enders rod. All the extremities were immobilized with plaster splint for about 6 to 8 weeks. Three months later, the lower limbs began to have functional exercises. By X-ray examination, the border between HBG and bone was clear in 2 weeks, after 1 month the clear border become blurred, and 2 months after operation, HBG was intermingled with bone. After 1 year there was neither absorption of bone nor HBG. No recurrence of the aptic lesion occurred in 1 year. HBG was a kind of artificial bone composed of hydroxyapatite and bioactive microcrystal glass, the latter contained silicon.It was characterized by its bioactivity, osteoinductivity and good tissue compatibility. The microcrystal would facilitate the growth of osseous tissues, which caused HBG intermingled with the surrounding bone. The source of HBG was abundant. It might be an ideal artificial bone.
Objective To evaluate the feasibility and the value of the layered cylindric collagenhydroxyapatite composite as a scaffold for the cartilage tissue engineering after an observation of how it absorbs the chondrocytes and affe cts the cell behaviors. Methods The chondrocytes were isolated and multiplied in vitro, and then the chondrocytes were seeded onto the porous collagen／h ydro xyapatite composite scaffold and were cultured in a three-dimensional environme n t for 3 weeks. The effects of the composite scaffold on the cell adhesivity, proliferation, morphological changes, and synthesis of the extracellular matrix were observed by the phase-contrast microscopy, histology, scanning electron micros copy, and immunohistochemistry. Results The pore diameter of the upper layer of the collagen-hydroxyapatite composite scaffold was about 147 μm. and the porosity was 89%; the pore diameter of the bottom layer was about 85 μm and the porosity was 85%. The layered cylindric collagenhydroxyapatite composite scaffold had good hydrophilia. The chondrocytes that adhered to the surface of the scaffold, proliferated and migrated into the scaffold after 24 hours. The chondrocytesattached to the wall of the microholes of the scaffold maintained a rounded morphology and could secrete the extracellular matrix on the porous scaffold. Conclusion The layered cylindric collagenhydroxyapatite composite scaffold has a good cellular compatibility, and it is ber in the mechanical property than the pure collagen. It will be an ideal scaffold for the cartilage tissue enginee ring.
Objective To study the effect and complication of repairing depressed fracture of frontal part with hydroxylapatite particulate artificial bone. Methods From January 1994 to December 2002, 13 patients were all diagnosed as having depressed fracture of frontal part with clinical and X-ray examinations. Thesmall incision before the hair-edge or local small incision was made. After opening the incision, we performed creeping decollement. Then the hydroxylapatite particulate artificial bone was implanted into the sites of the depressed fracture. The effect and complication were observed with clinical and X-rayexaminations in all patients 1 week, 1 month, 3 months after operation.Results The quantity of hydroxylapatite implanted was 10-30g. Primary healing was obtained in all cases without any complication. All cases were followed up for 3 months. The contours of the frontal part were restored well. Conclusion It is a good method to repair depressed fracture of frontal part with hydroxylapatite particulate artificial bone.
ObjectiveTo explore the effect of hydroxyapatite nanoparticle (nHAP) on hepatocellular carcinoma (HCC) and its mechanisms. MethodsThe literatures about the effect of nHAP on HCC were reviewed and summarized. ResultsAs a new nanoparticle, nHAP could suppress the DNA synthesis and subsequent division and proliferation of HCC cells through the inhibition of proliferating cell nuclear antigen (PCNA) and telomerase gene expression and increase of intracellular Ca2+. Moreover, nHAP was able to suppress the differentiation and metastases of HCC cells through the effect on the expressions of Paxillin and P130cas and the decrease of expressions of multiple drug resistance gene protein, microvessel density, and vascular endothelial growth factor. Finally, nHAP induced the apoptosis of HCC tumor cells by the regulation of bcl-2 and bax protein expressions. The combined use of nHAP and chemoembolization drugs could enhance the efficacy, prolong drug duration and reduce toxicity. ConclusionnHAP can inhibit the division, proliferation, differentiation, and metastases, and promote the apoptosis of HCC cells and combined use with chemoembolization drugs can enhance the efficacy and reduce toxicity.
Objective To prepare silver-containing hydroxyapatite coating (hydroxyapatite/Ag, HA/Ag) and investigate its antibacterial property and biocompatibil ity in vitro. Methods Vacuum plasma spraying technique was adopted to prepare HA/Ag coating on titanium alloy substrate (3% Ag). After incubating the HA/Ag and the HA coating under staphylococcus aureus and pseudomonas aeruginosa suspensions of 2% tryptic soy broth (TBS) medium for 2, 4 and 7 days, respectively, the biofilm on the coatings was examined by confocal laser scanning microscope, and the bacterial density and viable bacterial percentage of bacterial biofilm were calculated. Meanwhile, the micro-morphology of bacterial biofilm was observed by SEM, the cytotoxicity was detected via MTT and the biocompatibil ity of biofilm was evaluated by acute aemolysis test. Results Compared with HA coating, the bacterial biofilm’s thickness on the surface of HA/Ag coating witnessed no significant difference at 2 days after culture (Pgt; 0.05), but decreased obviously at 4 and 7 days after culture (P lt; 0.01). The bacterial density of the biofilm increased with time, but there was no significant difference between two coatings (P gt; 0.05) at 2, 4 and 7 days after culture. The viable bacterial percentage of the biofilms on the surface of HA/Ag coating decreased obviously compared with that of HA coating at 2, 4 and 7 days after cultureP lt; 0.01). The MTT notified the cytotoxic grade of both coatings was zero. The acute haemolysis assay showed that the hemolytic rate of HA/Ag and HA coating was 0.19% and 0.12%, respectively. Conclusion With good biocompatibil ity, significant antibacterial property against staphylococcus aureus and pseudomonas aeruginosa, no obvious cytotoxicity and no erythrocyte destruction, the vacuum plasma sprayed HA/Ag coating is a promising candidate for the surface of orthopedic metal implants to improve their osseointegration and antibacterial property.
Objective To evaluate the biocompatibility and safety of a novel orthopedics materials-graded zirconia(ZrO2)hydroxyapatite(HA) composite biomaterials. Methods First, ultrafine powers of ZrO2 and HA powder were prepared by chemical precipitation method, then graded ZrO2-HA composite was synthesized by dry-laying and sintering method. After the physiological saline and culture medium extracts of the composite were prepared, four experiments were conducted as follows:① The mouse acute toxic test consists of 2 groups(n=10). The extracts were intravenously injected to mice in the first group, and physiological saline to mice in the second group. The dose was 50 g/kg. Their toxicity manifestation, morality and the change of weight were recorded.② The standard curve of proliferation and metabolism of L929 cells was established. ③ The cytotoxinic test consists of 3 groups: materials group (extracts of the materials), positive control group (culture fluid with 0.64% phenol), and negative control group (RPMI-1640 culture fluid). Each of three was cultured with cell suspension, and then the morphology of the cells was observed, the relative proliferation rate (RGR) was calculated, and the toxicity was classified. ④ In vitrohemolytic test was divided into 3 groups: extracts, sterile distilled water (positive control) and 0.9% physiological saline. In each of three, 0.2 ml anticoagulant diluted fresh rabbit blood was added. The percentage of hemolysis was tested. ⑤ The muscle and implantation test were divided into 4 groups(n=3). The composite biomaterials were implanted into pygal muscleson either side and lateral condyles of femurs. After surgery, the rats of four groups were sacrificed at 12 and 24 weeks respectively.Tissue slice and scanning electronic microscopy were performed. Results General acute toxic test: no mouse died within 3 weeks; no toxicity symptom or adverse effects were shown within 3 days. The weight of materials group increased by 3.57±0.49 g, and the control group by 3.62±0.61 g, showing no statistically significant difference（Ρgt;0.05）.The standard curve of L929 cell perliferation and metabolism showed that their existed a positive correlation between the number of L929 cells and the perliferation. ③ Cytotoxinic test: cytosomes in the positive control group diminished and appeared round, there were pyknotic nucleus, the attached cells agglomerated; the toxicity was level Ⅳ. The morphology of cells in materials groupand negative control group was normal, and the number of them increased; the toxicity was level Ⅰand level 0, respectively. The MTT color experiments showed that positive control group was significantly lower than materials group and negative control group, showing statistically significant difference (Plt;0.01); there was no statistically significant difference between materials group and negative group.④ Hemolytic test: in vitrohemolytic rate of negative control group was0, of positive control group was 100%, and of materials group was 1.66%, which accords with the standard that hemolytic rate should be lower than 5% specified in ISO. ⑤ Implant test:No apparent rejection reaction took place after the composite was implanted; the composite bonded with the bones of the receptors firmly, which had good bonedinduced effect. Conclusion Graded ZrO2-HA composite bioceramic has good biocompatibility and is suitable for orthopedic biomaterials.
OBJECTIVE To confirm membrane-guided tissue regeneration in the healing course of segmental bone defects and study the mechanism. METHODS Segmental, 1 cm osteoperiosteal defects were produced in both radii of 12 rabbits. One side was covered with hydroxyapatite/polylactic acid(HA/PLA) membrane encapsulated as a tube. The contralateral side served as an untreated control. Healing courses were detected by radiographic and histologic examinations. RESULTS All control sides showed nonunion, whereas there were consistent healing pattern in test sides. CONCLUSION Membrane technique can promote bone regeneration.
Objective To evaluate the security and effectiveness of nano-hydroxyapatite/polyamide 66 (n-HA/PA66) cage in reconstruction of spinal stabil ity after resection of spinal tumor. Methods Between January 2008 and December2009, 11 patients with spinal tumor underwent surgical resection and strut graft with n-HA/PA66 cage. There were 6 males and 5 females with an average age of 44.5 years (range, 16-61 years). The average disease duration was 6.8 months (range, 2-14 months). The locations of lesions included cervical spine (2 cases), thoracic spine (6 cases), and lumbar spine (3 cases). Among them, there were 5 metastatic carcinomas, 2 giant cell tumors, 1 osteoblastsarcoma, 1 chondrosarcoma, and 2 non-Hodgkin lymphoma. According to Frankel criteria for nerve function classification, there were 1 case of grade A, 3 cases of grade B, 2 cases of grade C, 2 cases of grade D, and 3 cases of grade E. Results Incisions healed by first intention in all patients, no operative or postoperative compl ication occurred. Four cases of metastatic carcinoma died of primary disease during 5-9 months after operation. Seven cases were followed up 14.4 months on average (range, 10-18 months). All patients gained significant improvement of the neurological function at 3 months after operation. All cases obtained bone fusion and good spinal stabil ity without displacement and subsidence of the n-HA/PA66 cage. The intervertebral height of the adjacent segments was (110.5 ± 16.1) mm at 3 months after operation and (109.4 ± 16.2 ) mm at the final follow-up, showing significant differenecs when compared with the preoperative height [(97.5 ± 15.4) mm, P lt; 0.05], but no significant difference between 3 months after operation and the final follow-up. In 2 patients undergoing surgery via anterior approach, bilateral pleural effusion on both sides occurred and were cured after closed thoracic drainage. During the follow-up, 2 cases (1 chondrosarcoma and 1 giant cell tumor) relapsed and underwent reoperations. Conclusion n-HA/PA66 cage can provide satisfactory bone fusion and ideal spinal stabil ity without increasing the risk of recurrence and compl ications during the surgical treatment of spinal tumors. It is an idealselection for reconstruction of spinal stability.