The hydroxyapatite particles were used to repair 23 cases of depressed deformities of face. The patients were follwed up for 3 to 8 months and the short termresults were satisfactory. The operative procedure was briefly introduced. The advantages and attentions relevant to the operation were discussed.
ObjectiveTo construct bone morphogenetic protein 2 (BMP-2) gelatin/chitosan hydrogel sustained-release system, co-implant with induced pluripotent stem cells (iPS) derived mesenchymal stem cells (MSCs) to hydroxyapatite (HA)/zirconium dioxide (ZrO2) bio porous ceramic foam, co-culture in vitro, and to explore the effect of sustained-release system on osteogenic differentiation of iPS-MSCs.MethodsBMP-2 gelatin/chitosan hydrogel microspheres were prepared by water-in-oil solution. Drug encapsulation efficiency, drug loading, and in vitro sustained release rate of the microspheres were tested. HA/ZrO2 bio porous ceramic foam composite iPS-MSCs and BMP-2 gelatin/chitosan hydrogel sustained release system co-culture system was established as experimental group, and cell scaffold complex without BMP-2 composite gelatin/chitosan hydrogel sustained release system as control group. After 3, 7, 10, and 14 days of co-culture in the two groups, ALP secretion of cells was detected; gene expression levels of core binding factor alpha 1 (Cbfa1), collagen type Ⅰ, and Osterix (OSX) were detected by RT-PCR; the expression of collagen type Ⅰ was observed by immunohistochemical staining at 14 days of culture; and cell creep and adhesion were observed by scanning electron microscopy.ResultsBMP-2 gelatin/chitosan hydrogel sustained-release system had better drug encapsulation efficiency and drug loading, and could prolong the activity time of BMP-2. The secretion of ALP and the relative expression of Cbfa1, collagen type Ⅰ, and OSX genes in the experimental group were significantly higher than those in the control group at different time points in the in vitro co-culture system (P<0.05). Immunohistochemical staining showed that the amount of fluorescence in the experimental group was significantly more than that in the control group, i.e. the expression level of collagen type Ⅰ was higher than that in the control group. The cells could be more evenly distributed on the materials, and the cell morphology was good. Scanning electron microscopy showed that the sustained-release system could adhere to cells well.ConclusioniPS-MSCs have the ability of osteogenic differentiation, which is significantly enhanced by BMP-2 gelatin/chitosan hydrogel sustained-release system. The combination of iPS-MSCs and sustained-release system can adhere to the materials well, and the cell activity is better.
OBJECTIVE: To evaluate the clinical effect of drilling procedure following the hydroxyapatite orbital implantation. METHODS: From February 1996 to April 2000, 146 consecutive patients who received hydroxyapatite orbital implant were drilled and inserted a motility peg 6 to 16 months after hydroxyapatite implantation. Among them, there were 97 males and 49 females, aged from 18 to 60 years old, of the 146 motility pegs, 36 were sleeved pegs and 110 were nonsleeved. Goldman visual field analyzer was applied to measure the degree of artificial eye’s movement before and after drilling. RESULTS: Followed up for 1 to 40 months, no secondary infection occurred. The mobility of the prosthesis increased from (18.7 +/- 3.8) degrees preoperatively to (42.3 +/- 3.7) degrees postoperatively. CONCLUSION: The delayed drilling procedure and motility peg insertion improve the range of movement and the sensitivity of the artificial eye with a low rate of complications.
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 study an optimal ratio of small intestinal submucosa (SIS) and (hydroxyapatite-tricalcium phosphate,HA-TCP,SIS/HA-TCP) compositions according to the effect of SIS/HA-TCP compositions with different ratios on repairing rabbit femoral condyle defect. Methods Thirty-six rabbits were made into bone defect models of 6 mm in diameter and 10 mm in depth in both sides of femoral condyles. Three different ratios of SIS/HA-TCP compositions (w/w: 1, 0.5, 0.25) were implanted into rabbit femoral condyle defect. After 2, 4, 8 and 12 weeks of operation, the repair effect wasobserved grossly. The histological evaluations were performed by histological scoring system and computer imaging analysis system. Results The amount of new bone formation in SIS/HA-TCP(0.5) group was more than that in SIS/HA-TCP(1) and SIS/HA-TCP(0.25) groups. Histological observation: In SIS/HA-TCP(1) group, few new bone formation was seen and bone defect was repaired in the 12th week. In SIS/HA-TCP(0.5) group, immature woven bone was found in the defect in the 2nd week; more immature woven bone appeared and formed trabeculae in the 4th week; the regenerated bone was vigorously growing into the interspaces of the implanted materials in the 8th week; the implanted materials was basically replaced by bony structure and the lamellar bone appeared in the 12thweek. The results of SIS/HA-TCP (0.25) group were similar to that of SIS/HA-TCP(0.5) group. The histological scoring was higher in SIS/HA-TCP(0.5) and SIS／HA-TCP(0.25) groups than that in SIS/HA-TCP(1) group (Plt;0.05) in the 2nd, 4th, 8th, and 12th weeks. The scoring was higher in SIS/HA-TCP(0.5) roup than that in SIS/HA-TCP(0.25) group in the 2nd and 12th weeks(P＜0.05). In new bone formation and the degradation of HA-TCP, SIS/HA-TCP(0.5) and SIS／HA-TCPC(0.25) groups were superior to SIS/HA-TCP(1) group(Plt;0.05), SIS/HA-TCP(0.5) group was superior to SIS/HA-TCP(0.25) group (Plt;0.05). Conclusion SIS/HA-TCP(0.5) has better effects of repairing bone defect and it can be used as a reference ratio in constructing bone scaffolds.
Objective To investigate the influence of different dose levels of hydroxyapatite/tricalcium phosphate (HA/TCP) on the proliferation and alkalinephosphatase (ALP) activity of rabbit osteoblasts. Methods Three different doselevels of HA/TCP (10%, 40%, 70%) were co-cultivated with rabbit osteoblasts respectively. The proliferation and ALP expression capacity of osteoblasts were examined with MTT method and enzyme histochemistry once every 24 hours until 5 days. Three control groups of other materials were treated and examined in the sameway: rabbit osteoblasts as normal control; polyvinylchloride as positive control; titanium alloy as negative control. Results There was remarkable timeeffect relationship in the proliferation of osteoblasts. Ten percent HA/TCP did not affect osteoblasts growth while 40% HA/TCP could slow the cell growth rate down though time-effect relationship still existed. The proliferation of osteoblasts stagnated when co-cultivated with 70% HA/TCP. On the other hand, 10% HA/TCP could cause reversible damage on ALP activity of osteoblasts, whereas when the dose was40%, and the cultivation lasted 6 days the damage was irreversible. Three different dose levels of titanium alloy (10%, 40%, 70%) had no effect on the proliferation or ALP activity of osteoblasts. Conclusion Dosage is an important factor affecting the biocompatibility evaluation of biomaterial. It suggests that dose choosing should be more specified upon each individual biomaterial. It also indicates that ALP may be a good supplementary index of the cell compatibility of material.
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 study the effect of collagen/hydroxyapatite(CHA) instead of autogenous bone transplantation on repairing the mandibular defects. METHODS: Ten Chinese experimental minipigs were made 2 cm bone defects in diameter in the mandible. The experimental group was implanted CHA, while the control group was implanted autogenous bone. The basic parameters of bone dynamics were determined by bone metrology. RESULTS: There was remarkable difference between the two groups in the mean distance and mineralization apposition rate of double label bands marked by tetracycline(P lt; 0.05), while the mean osteoid seam width and mineralization lag time had no remarkable difference(P gt; 0.05). It suggested that CHA had good osteogenesis. The collagen in CHA offered the condition of bone mineralization, and the mineralization peak of experimental group was present at 4 weeks earlier than that of control group (8 weeks). CONCLUSION: CHA may be a substitute of autogenous bone transplantation in repairing the mandibular defects, and the second operation for offering the implanting bone is avoidable, therefore, CHA may be an ideal material to repair bone defects.
Objective To investigate and compare the osteogenic potential of three kinds of calcium phosphate ceramic as carriers for recombinant human bone morphogenetic protein-2(rhBMP-2) in vivo.Methods BCPceramics (HA,TCP,HA/TCP) impregnated with rhBMP-2 (experimental groups) and without rhBMP-2(control groups) were implanted into 6 muscles pockets on the dorsum of 3month-old Wistar rabbits. The rabbits were sacrificed 2, 4 and 8 weeks after implantation and bone induction was estimated by alkaline phosphatase(ALP) activity measurement. The implants were also examined histologically and histomorphometrically by HE staining and computerized graphical analysis. Results The ALPactivity of implants withrhBMP-2 was higher than that of control groups(P＜0.05), but there was no difference between 2 and 4 weeks in experimental groups. In all experimental groups,theimplants exhibited that new bone formation increased with the lapse of time. The amount of new bone formation is more in -HA/rhBMP-2 group than in the other two group in the 2nd and 4th weeks, but there was no difference between them (P＞0.05).In the 8th week, the amount of bone formation was most in HA/TCP with -rhBMP-2, and was more than that in the 2nd and 4th weeks. Whereas in control groups, there was only fibrous connective tissue. Conclusion HA/TCP- is a good carriers of rhBMP-2 and can be used as bone substitutes clinically.
In order to investigate the stability of Hydroxyapatite (HA) coated material, the plasma-sprayed coatings of HA were divided into four groups: 1. Keeping in water vapour at 125 degrees C, with a pressure of 0.15 MPa for 6 hr; 2. Heating at 650 degrees C in air for half an hr; 3. Keeping in water vapour at 490 degrees C, with a pressure of 0.01 MPa for 2 hr; and 4. The control. The XRD, FTIR analysis and the dissolution test were carried out. The results showed: 1. The degree of crystalization in XRD analysis was 3. gt; 1. gt; 2. gt; 4.; 2. The ampitude of OH- peak in FTIR analysis was 3. gt; 1. gt; 2. gt; 4. and 3. The dissolution rate in tris-HCl buffer was 3. lt; 1. lt; 2. lt; 4. The conclusions were 1. The treating with water vapour could decrease the transformation temperature which was needed to convert the amorphous phase into cystalline phase; 2. Water vapour treatment could accelerate the transformation of Z-TCP, TCPM into crystalline HA; 3. Water vapour treatment could promote the structural integrity of plasma--sprayed coated of and HA and 4. Water vapour treatment could lower the dissolution rate of HA coated in Tris-HCl buffer.