Magnetic resonance signal detection of superparamagnetic iron oxide nanoparticles and its biological effects on endothelial cells / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the magnetic resonance (MR) signal changes of superparamagnetic iron oxide (SPIO) and its biological effects on endothelial cells.</p><p><b>METHODS</b>The citric-acid coated SPIO was synthesized by co-precipitation method. The human umbilical vein endothelial cells (HUVECs) were incubated with SPIO for 24 h in culture medium at iron concentration of 0.01, 0.05, 0.10, 0.15 mg/ml (experimental groups), and the cells incubated without SPIO served as control groups. The uptake efficiency of intracellular iron was measured by Prussian blue staining, and the cell viability was monitored by Calcein-AM method. The cell cytoskeleton (F-actin and tubulin), adherence and migration capacity were measured by immunofluorescence staining. The iron oxide nanoparticles distribution and the cellular organelle change were monitored by transmission electron microscopy (TEM). Quantification of particle uptake was measured by atomic absorption spectrometry. The MR signal of endothelial cells after labeling was monitored by Philips 3.0 T MR scanner.</p><p><b>RESULTS</b>SPIO was uptaken by HUVECs in a concentration-dependence manner. Compared with the control group, cell viability was decreased along with the increase of iron concentration. Compared with the control group, the cell cytoskeleton was markedly disorganized and the FAK spot was bigger and sparser.The nanoparticles were mainly existed in lysosomes, and the higher concentration of SPIO, the more lysosomes and vacuoles presented in the cells. The iron content per cell was (55.86 +/-9.935) pg when the SPIO concentration was 0.15 mg/ml. The MR image showed that the cells labeled with SPIO resulted in the decrease of MR signal.</p><p><b>CONCLUSION</b>The cells labeled with SPIO can be detected by MR. The cell viability, cytoskeleton, adherence and migration capacity of HUVECs are affected by citric-acid coated SPIO in a concentration-dependent manner.</p>

Treatment of acute and chronic osteomyelitis with negative pressure wound therapy / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the treatment of acute and chronic osteomyelitis with negative pressure wound therapy.</p><p><b>METHOD</b>Thirty cases of acute and chronic osteomyelitis were treated with negative pressure wound therapy, assisted with debridement, autodermoplasty and myo-cutaneous flap surgery.</p><p><b>RESULTS</b>No evidence of relapse was found in all cases treated with negative pressure wound therapy. All the patients were followed up, range from 6 to 23 months, the average was 13.6 months.</p><p><b>CONCLUSION</b>The negative pressure wound therapy maybe a simple, effective and inexpensive method, and could be one of the favorable therapy in the treatment of acute and chronic osteomyelitis.</p>

Experimental study of core binding factor a1 gene-modified rabbit skin fibroblasts enhance bone defect repair / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate bone defect healing by true bone ceramic complex carrying core binding factor a1 (Cbfa1) gene modified rabbit skin fibroblasts.</p><p><b>METHODS</b>Transfect rabbit skin fibroblasts (RSF) with both eukaryotic expression vector pSG5 which could express Cbfa1 gene and pSG5. After being cultured for 48 h, the transfected RSF were seeded into true bone ceramic (TBC) of 2 cm in length and 4 mm in diameter to construct pSG5-Cbfa1/RSF/TBC complex and pSG5/RSF/TBC complex. Forty-eight bone defect model rabbits were randomized into four groups, each has 6 rabbits (12 radius), due to different treatment. group I: with pSG5-Cbfa1/RSF/TBC complex, group II: with pSG5/RSF/TBC complex, group III: with TBC, Group IV: empty control. After being seeded and cultured for about 24 h the complexes were implanted into 2 cm long bone defects in the middle of bilateral radius of rabbits. The radius were inspected by X-ray and then the specimens were collected at the end of the fourth and twelfth weeks after operation. Then, the specimens were decalcified and histologically investigated with Hematoxylin eosin staining and Masson staining methods. Newly synthesized trabecular bone was inspected by image analysis system and the strength of bone defect area treated with graft-implantation was tested with biomechanical method-three point bending test.</p><p><b>RESULTS</b>In group I, trabecular bone was actively synthesized to generate a great amount of trabecular bone and osteon. Preliminary union and bone defect healing were completed with good biomechanical characteristics. There were no newly synthesized trabecular in the other three groups, and bone defect healing were not discovered. The amount of newly synthesized trabecular bone and the results of biomechanical testing differed significantly between group I and the other three (P < 0.01). The efficacy of group I was significantly better than that of the other three groups.</p><p><b>CONCLUSION</b>True bone ceramic complex composed with Cbfa1 gene modified rabbit skin fibroblasts can effectively heal bone defect in rabbits.</p>

Experimental study on the osseointegration of nanophase hydroxyapatite biograde-coated implants / 中华外科杂志

<p><b>OBJECTIVE</b>To study the osseointegration of the nanophase hydroxyapatite biograde-coated implants and host bone.</p><p><b>METHODS</b>Nanophase hydroxyapatite biograde-coated implants, hydroxyapatite biograde-coated implants and noncoated Ti-6Al-4V implants were inserted into both femoral of Beagle canines the tissue response, dynamic osteogensis and SEM were studied at 4, 8 and 12 weeks.</p><p><b>RESULTS</b>The degradation of nanophase hydroxyapatite was slower than hydroxyapatite, dynamic osteogensis and the form of osteoblast were better than the control groups.</p><p><b>CONCLUSION</b>The biological reaction of Nanophase hydroxyapatite biograde-coated implants is better than hydroxyapatite coated implant.</p>