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Objective: To evaluate the effect of pure titanium modified by bioadhesive RGD peptide on the early attachment, growth and proliferation of osteoblasts. Methods: The titanium samples were hydroxylated by alkali/hot water aging and sol-gel layer-by-layer deposition technique. Afterwards, the terminal -NH_2 group was introduced to the titanium surface by organosilane APTMS self-assembled monolayers and the functional group -NH_2 was further reacted with EDC/NHS by which RGD peptides was covalently immobilized to titanium. The efficiency of this bioreactive surface in promoting cell attachment and the competitive inhibition effect of RGD peptide with different concentrations were observed by calculating the amount of osteoblasts attached on the modified titanium. The growth and proliferation were observed by MTT method and scanning electronic microscopy. Results: The cell adhesion percentage of the RGD modified titanium group was much higher than that of the other groups. The RGD peptide solutions with higher concentration had stronger inhibitory impact on the cell adhesion onto the titanium surface. The cell growth, morphology and proliferation on the RGD peptide modified titanium were better than other groups. Conclusion: Bioadhesive peptide can be chemically grafted onto the titanium surface by means of self-assembled monolayers technique. The cells′ biological behaviors on the surface of RGD immobilized titanium are greatly improved in vitro.
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Objective To assess the value of ultrasound guided percutanuous automatic biopsy of mediastinal tumors.Method Forty-six consecutive biopsies were performed on forty-six patients suffered from mediastinal tumor included 14 thymomas,12 lymphomas,9 metastasis carcinomas,5 mediastinal lung carcinomas,3 teratomas,2 neuroblastomas,1 granulosa cell tumor.Under US guidance,a 18-guage core needle with automatic biopsy device was used.Specimen was fixed with 10% formaldehyde solution.Results The procedure of puncture was successful in all patients.The positive rate histologically was 89%(41/46).No complication (such as hemorrhage,pneumothorax and dyspnoea) was happened.Conclusion We consider that the ultrasound-guided percutaneous needle biopsy is a safe and reliable method for the histological diagnosis of mediastinal tumors.
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Objective To evaluate the results of liver carcinoma treated by radiofrequency ablation(RFA) with color Doppler ultrasonography(CDU). Methods Hemodynamic changes of the interior and periphery of 212 nodules of liver carcinoma in 152 patients were investigated by CDU one week before and one month after RFA. Results Blood flow signals were found in 187 cancerous nodules before RFA, and were chiefly from mixed arterio-venous blood supply. After RFA, the blood flow signals of these 187 cancerous nodules completely disappeared in 133, were reduced in 40 and did not change in 14. Peripherar blood flow did not change in 51.2% of the tumors. Conclusions CDU is useful in evaluating the therapeutic effect of RFA in patients with liver carcinoma and may provide information for further treatment.