ABSTRACT
OBJECTIVE To investigate the factors influencing the effects of disinfection of HBV on dental hand piece. METHODS After polluted with HBV positive serum,the dental hand piece was disinfected with sterilizer at the condition of 134℃ for 5 minutes according different treatment procedures.The samples were then taken and detected HBsAg by the automatic enzyme immune analyzer using the third generation EIA agent.The efficacy of disinfection of HBV was presented by the reaction of HBsAg detection. RESULTS If the dental hand piece was sterilized directly not cleansed using clean water after pollution and dried in room temperature,there were 96.87% of the samples being HBsAg positive,and the polluted but dried hand piece,even cleansed there were 87.5% of positive result, even if prolonged the time of sterilization and the frequencies of vacuumization,the HBsAg positive rate of the sample was still up to 56.25%.But if the hand piece was irrigated and cleansed immediately after pollution and sterilized,all samples were HBsAg negative. CONCLUSIONS Whether or not cleansed immediately is the most important factor influencing the efficacy of hand piece sterilization after pollution.
ABSTRACT
Objective:To investigate the existence condition of hepatitis B surface antigen(HBsAg) termina-tion codon bias.Methods: A total of 174 reference sequences of all kinds of Hepatitis B virus(HBV) genotypes were chosen from GenBank,and compared by BioEdit.Then secondary structure of RNA was constructed and analyzed together.Results:(1) There were two types of HBsAg termination codon: TAA and TGA in 174 reference sequences.TAA was in 124 cases(71.26%);and TGA in 50 cases(28.74%).(2) There was codon bias selection in HBsAg termination codon,and it could affect the secondary structure of RNA and amino acid sequence encoding protein.Conclusion: HBsAg termination codon bias exists and may be related to RNA structure and the conservatiom of protein function in the evolutionary progress.