ABSTRACT
Focusing on the poor mechanical strength of porous bioceramics bone scaffold, and taking into account of the good mechanical properties of biodegradable magnesium alloy, we proposed a novel method to fabricate magnesium alloy/bioceramics composite bone scaffold with stereolithography double channels. Firstly, a scaffold structure without mutually connected double channels was designed. Then, an optimized bioceramics scaffold was fabricated according to stereolithography and gel-casing. Molten AZ31 magnesium alloy was perfused into the secondary channel of scaffold by low-pressure casting, and magnesium alloy/bioceramics composite bone scaffold was obtained when magnesium alloy was solidified. The compression test showed that the strength of bioceramics scaffold with only one channel and without magnesium alloy was (9.76 ± 0.64) MPa, while the strength of magnesium alloy/bioceramics composite scaffold with double channels was (17.25 ± 0.88) MPa. It can be concluded that the magnesium alloy/bioceramics composite is obviously able to improve the scaffold strength.
Subject(s)
Humans , Alloys , Biomechanical Phenomena , Bone and Bones , Ceramics , Magnesium , Materials Testing , Porosity , Tissue ScaffoldsABSTRACT
Objective To explore the influence of alpha-fetoprotein (AFP) on the expression of drug-resistance gene MDR1 and chemotherapeutic sensitivity in hepatocellular carcinoma (HCC) cells.Methods A HCC cell line SMMC-7721/AFP, which was stably transfected with AFP gene, was established.mRNA and protein expressions of AFP and MDR1 were detected by real-time PCR and Western Blot,respectively.The sensitivity of SMMC-7721/AFP and SMMC-7721/EGFP cells with or without MDR1 silencing by siRNA to doxorubicin was tested by MTT assay.Immunohistochemistry was used to detect the expression of MDR1 genes-coded protein Pgp in 60 cases of HCC tissues, and the relationship between Pgp expression and serum AFP levels was analyzed.Results AFP mRNA and protein could be detected in SMMC-7721/AFP cells, but not in control cells, indicating that the AFP stably transfected cell line was successfully established.MDR1 mRNA and protein levels were higher in SMMC-7721/AFP cells than those in SMMC-7721/EGFP cells.MDR1 mRNA level in SMMC-7721/AFP cells was (52.7 ± 1.5) times as high as that in SMMC-7721/EGFP cells (P ＜ 0.05).The resistance to doxorubicin was increased by (12.8 ± 1.1) times after AFP transfection (P ＜ 0.05).The chemosensitivity to doxorubicin was increased after the expression of MDR1 was knocked down by siRNA.The expression of Pgp in HCC tissues was positively correlated with the serum AFP levels.Conclusion AFP could induce drug-resistance to doxorubicin in HCC cells by increasing the expression of MDR1.
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Objective To compare the clinical effect of manual aspiration thrombectomy versus systemic thrombolysis for acute lower extremity deep venous thrombosis of mixed type.Methods The clinical data of 380 patients with acute lower extremity deep venous thrombosis of nixed type was analyzed retrospectively,who were classified into two groups according to treatment methods.Group A (229 cases):the ipsilateral femoral vein was accessed under local anesthesia,a 12-14 F sheath was introduced via a guide wire to aspirate iliofenoral thrombus.As for the femoropopliteal thrombus,a Fogarty balloon catheter was introduced to pull thrombus to iliac vein,then mechanical aspiration thrombectomy was performed.One hundred and thirteen patients with stenosis or occlusion of comnon iliac vein were treated with adjunctive PTA and stenting.As for the residual thrombus bclow popliteal vein,a small dose urokinase vas given to thrombolysis and heparin anticoagulation after procedure.Group B(151 cases) were treated by systemic thrombolysis and anticoagulation with heparin.Results The swelling and pain of affected limbs of group A began to relief after operation immediately,but these times of group B was 3-7 days after operation.The thrombus was eliminated completely(Grade Ⅰ):goup A was better than group B (63.32％ vs 37.09％) (x2 =20.53,P =0.002).Conclusions The manual aspiration thrombectomy was superior to simple systemic thrombolysis in treating acute lower extremity deep venous thrombosis of mixed type,especially in protecting the normal valve function that was better than thrombolysis,aspiration thrombectomy with adjunctive iliac vein angioplasty was a more reasonable method to treat acute LEDVT.
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Objective To discuss the operative difficulties and management in laparoscopic thyroidectomy.Method The clinical data of 169 cases undergoing laparoscopic thyroidectomy were retrospectively analyzed.Result Among 169 cases,only 2 cases were switched to open surgery.Among the other 167 cases local thyroidectomy for thyroid adenoma Was performed in 37 cases,one side subtotal thyroidectomy in 63 cases,two side subtotal thyroidectomy in 42 cases,laparoscopic subtotal thyroideetomy was done in 20 cases for Grave's disease,and radical thyroidectomy was undeRaken in 5 cases of thyroid carcinoma.Postoperatively fat colliquation occurred in 2 cases,pneumohypoderma,skin bruise and temporary vocal dullness or hoarsness in 1 each case.There was no postoperative recurrent laryngeal nerve injury,nor that of the parathyroid gland. Conclusions Laparoscopie thyroidectomy has its own intraoperative difficulties. Accurate operative skills and careful perioperative management can decrease the occurrence of complications.
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Objective To investigate the effects of Tet-on gene regulated HIF-1?expression on cell apoptosis of hepatoma cells in vitro. Methods The apoptosis of hepatocellular carcinoma cell lines HePG2 was measured after HIF-1?expression was activated in HePG2 in vitro by Tet-on expression system. Results The amplified products were confirmed as the cDNA of HIF-1?by DNA sequencing, and obtained pTHE-HIF-1?was verified by endonuclease digestion. The HePG2Tet-on cells express HIF-1?constantly. After being incubated under different concentrations of doxycycline for 48 h, HIF-1?gene could inhibit HePG2 cell apoptosis. The apoptosis rates were 59. 6%、50. 9%、38. 1%、30. 5%、23. 9%、18. 3% respectively when the concentrations of doxycycline were 0?g/ml,0. 02?g/ml,0. 2?g/ml、1?g/ml、2?g/ml,5?g/ml (P