Molecular imaging is a newly rising branches of science which comes from molecular biology technology and modern medical imaging,and it would be the development tendency of mendiacl imaging. This article briefly introduces the basal principle of molecular imaging,the difference and correlation between molecular imaging and traditional medical imaging and the development prospect of medical imaging.

Objective To construct the adenoviral vector carrying Mus-?NGF gene and to study the expression of the gene in the marrow mesenchymal stem-cells(MSCs).Methods Mus-?NGF cDNA was cloned from mice glandulae maxillaries whole mRNA by reverse-transcription polymerase-chain-reactions.The Mus-?NGF cDNA was positively cloned into the adenoviral shuttle vector pAdtrack carrying cytomegalovirus promoter(CMV)and tag-protein(GFP),and then homologous recombined into competent BJ5 183 cells with the adenoviral backbone plasmid pAdeasy-1.The recombinant adenoviral plasmid was identified by restriction enzymes and transfected into HEK293 cells to package and amplify recombinant adenoviral particles which was capable of infecting and would express ?NGF and GFP proteins.After the adenovirus infected the MSCs,the expression was observed via fluorescent microscrope and detected using immunocytochemical method.The secretion of NGF was detected by WB.Results The recombinant adenoviral vector carrying Mus-?NGF gene was constructed and confirmed by restriction endonuclease enzyme analysis.The relucent green fluor-light would be observed in the MSCs.IHC showed that Mus-?NGF gene was exactly transcripted and expressed in the MSCs,and the secretion of NGF was confirmed.Conclusion The exogenous gene,such as ?NGF,an be imported into the MSCs efficiently by recombinant adenoviral vector,and can be expressed and secreted successfully in the cells.It improves foundation for the celluar transplant and gene intervention of MSCs expressing NGF in inner ear.

Objective To investigate the distribution of NGF in the cochleae of neonate rats and to explore the mechanism of NGF in the auditory path. Methods Twenty healthy neonate SD rats aged 5-7 d were selected and their cochlear paraffin sections were labeled with a rabbit anti-NGF polyclonal antibody by SP method. Results The membranous labyrinth of neonate rats appeared similar to triangle and NGF expression was observed in immature corti’s organ, in spiral ganglion cells and in nerve fibers throughout the cochlea. The distribution located in both cytoplasm and nucleus. Conclusion The distribution of NGF was closely related to survival and maturation of spiral ganglion cells and hair cells in rats aged 5-7 d.