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Objective To study the effects of using 25 kDa linear and branched PEI to transfer plasmid DNA pEGFP -C1 (pDNA ,encoding the enhanced green fluorescent protein reporter gene ) to the basilar membrane of the C57BL/6 mice cochlea in vitro .Methods L -PEI/pDNA and B -PEI/pDNA polyplexes were generated in 0 .1M phosphate buffer solution (PBS) or 5% glucose solution .Polyplexes were characterized by transmission electron mi-croscopy .Agarose gel retardation assay was used to determine the plasmid binding ability of L -PEI and B -PEI . The toxicity was investigated by MTT assay .The transfection was firstly evaluated in 293T cell line ,and then the appropriate amount of PEI and plasmid were applied for cochlear explant transfection of P4 mice pups .Results Un-der the same condition ,B -PEI had better transfection efficiency than L -PEI ,but its toxicity was also higher . When generated in PBS ,the polyplexes had lower toxicity than in glucose solution .L -PEI-pDNA nanoparticles could transfect the spiral limbus fibrocytes ,some spiral ganglion neurons and supporting cells ,but the efficiency was low .Conclusion L -PEI could be used as the non -viral vector for the transfection of the cultured basilar mem-brane of P4 mice pups ,but it should be modified to reach higher efficiency .
ABSTRACT
OBJECTIVE@#To investigate the treatment for benign tumor of external auditory canal by carbon dioxide laser under microscope.@*METHOD@#Ten cases of benign tumor of external auditory canal were treated by carbon dioxide laser under microscope. The curative effects and complications were observed.@*RESULT@#Ten cases of benign tumor of external auditory canal were satisfied after operation without any complications. There were no recurrences during 3 months to 2 years of follow up.@*CONCLUSION@#The operation for benign tumor of external auditory canal by carbon dioxide laser under microscope was easy, safe and effective.