Document 0742
 DOCN  M94A0742
 TI    Mechanisms of AZT resistance in HIV isolates.
 DT    9412
 AU    Buchanan L; Tachedjian G; Birch C; Virology Department, Fairfield
       Hospital, Victoria.
 SO    Annu Conf Australas Soc HIV Med. 1993 Oct 28-30;5:101 (poster no. 53).
       Unique Identifier : AIDSLINE ASHM5/94348913
 AB    AIM: To investigate the susceptibility of the reverse transcriptase (RT)
       and ribonuclease H (RNase H) from AZT-sensitive (AZT-S) and
       AZT-resistant (AZT-R) HIV isolates to AZT-triphosphate (AZTTP) and
       AZT-monophosphate (AZTMP). METHODS: Isolates obtained from a patient
       before and after long-term AZT therapy were examined for susceptibility
       to AZT. RT and RNase H from these isolates were analysed in in vitro
       assays to determine their susceptibilities to AZTTP and AZTMP
       respectively. RESULTS AND CONCLUSIONS: Amino acid changes occurring in
       the HIV RT after long-term AZT therapy result in phenotypic AZT
       resistance. However, altered susceptibility cannot be definitely
       associated with the effects of AZTTP on RT or AZTMP on RNase H using
       enzyme assays, suggesting that the assay procedures used are not optimal
       or that alternative mechanisms of action are operating for AZT.
 DE    Drug Resistance, Microbial/GENETICS  Human  HIV/*DRUG EFFECTS/GENETICS
       Mutation/GENETICS  Phenotype  Reverse Transcriptase/GENETICS
       Ribonuclease H, Calf Thymus/GENETICS  Zidovudine/*PHARMACOLOGY  MEETING
       ABSTRACT

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).