Prophylactic ZDV therapy prevents early viremia and lymphocyte decline but not primary infection in feline immunodeficiency virus-inoculated cats.

Prophylactic zidovudine (ZDV) therapy was evaluated in the feline immunodeficiency virus (FIV)-inoculated cat model for HIV-1 infection in humans. ZDV treatment (30 mg/kg/day via continuous subcutaneous infusion) was initiated 48 h prior to virus inoculation and continued for 28 days. Transient plasma antigenemia evident in six of six untreated cats at week 2 post-inoculation (pi) was absent in the ZDV-treated cats although at 10 and 14 weeks pi (6 and 10 weeks after drug treatment), one of the ZDV-treated cats had low-level antigenemia. Both CD4 and CD8 lymphocyte numbers were consistently higher in the ZDV-treated cats when compared to both the FIV-inoculated untreated cats and the virus-naive, age-matched controls. CD4:CD8 ratios were lower for the ZDV-treated cats than either the FIV-inoculated untreated or virus-naive, control cats. The decreased CD4:CD8 ratios were the result of an increase in CD8 lymphocytes in the ZDV-treated cats while decreased ratios in the FIV-inoculated untreated cats were due to cell loss. Both ZDV-treated and untreated cats showed nearly identical FIV-specific antibody responses beginning 2 weeks pi. Polymerase chain reaction (PCR) results from blood lymphocytes showed that six of six ZDV-treated and six of six untreated cats were positive for FIV-specific gag sequences. Although primary infection was not prevented, these results suggest that prophylactic ZDV therapy deterred early systemic spread of infection mediated by viremia and delayed absolute CD4 and CD8 lymphocyte decline.

Normal and retarded children's understanding of semantic relations in different verbal contexts.

The effect of different semantic relations presented in different verbal contexts to language retarded and normal children at the one-and two-word stage of development was studied. No significant difference was found between the performance of mentally retarded language-disordered and normal children on the verbal comprehension task. Both groups of children performed best on the possessive, next on the agent-object, then actor-action, and poorest on the locative relations. Finally, nonsense, telegraphic, and expanded contexts did make a difference in the children's understandings with expanded being the best, telegraphic next, and nonsense contexts poorest. Theoretical and clinical implications are discussed.