Objective To prepare poly (lactic-co-glycolic acid) (PLGA) microspheres that contain recombinant epidermal growth factor and then evaluate the effect of these sustained release in vitro.Methods Human serum albumin (HAS) microspheres were prepared with a double-emulsification solvent evaporation method.Experiment was designed to optimize the preparation condition of recombinant human epidermal growth factor (rhEGF)-loaded microspheres.Characters of optimal rhEGF-loaded microspheres were analyzed.In-vitro dissolution tests were performed on the microsperes.Results The speed of first emulsification,the concentration of PLGA,the concentration of polyvinyl alcohol (PVA),and the ratio of inner water to organic phase affected the particle size and the encapsulation ratio.The polymer's individual specificities especially density,molecular weight,polymerization,the diameter of microsphere,and the encapsulation efficiency were the crucial factors to influence the speed and time of drug release from microspheres in vitro.The optimal microspheres possessed a smooth and round appearance.It also showed good lente liberantes effect in vitro.Conclusions The optimal microspheres possessed a smooth and round stable appearance and showed good lente liberantes effect in vitro.This technique was simple and had a good reproducibility.

We report a complete genomic sequence of rare isolates (minor genotype) of the SARS-CoV from SARS patients in Guangdong, China, where the first few cases emerged. The most striking discovery from the isolate is an extra 29-nucleotide sequence located at the nucleotide positions between 27,863 and 27,864 (referred to the complete sequence of BJ01) within an overlapped region composed of BGI-PUP5 (BGI-postulated uncharacterized protein 5) and BGI-PUP6 upstream of the N (nucleocapsid) protein. The discovery of this minor genotype, GD-Ins29, suggests a significant genetic event and differentiates it from the previously reported genotype, the dominant form among all sequenced SARS-CoV isolates. A 17-nt segment of this extra sequence is identical to a segment of the same size in two human mRNA sequences that may interfere with viral replication and transcription in the cytosol of the infected cells. It provides a new avenue for the exploration of the virus-host interaction in viral evolution, host pathogenesis, and vaccine development.
Base Sequence ; China ; Cluster Analysis ; Gene Components ; Genetic Variation ; Genome, Viral ; Genotype ; Molecular Sequence Data ; Phylogeny ; Reverse Transcriptase Polymerase Chain Reaction ; SARS Virus ; genetics ; Sequence Analysis, DNA ; Severe Acute Respiratory Syndrome ; genetics