Pay-for-performance in safety net settings: issues, opportunities, and challenges for the future

A major trend among Medicaid programs is the adoption of pay-for-performance (P4P) programs, but little evidence exists about the impact of these programs on quality improvement. Our in-depth case investigation of P4P in two safety net settings suggests that such programs may have minimal short-term effect on quality improvement. Two potentially important barriers for P4P in safety net settings are limited motivational effects from financial incentives and complex patient care requirements. We did not uncover any opposition against P4P among providers, nor did we find any evidence that P4P programs may compromise quality of care through unintended consequences. Overall, study results point to opportunities to improve the design and implementation of P4P programs in safety net settings.

A nucleotide substitution in the tRNA(Lys) primer binding site dramatically increases replication of recombinant simian immunodeficiency virus containing a human immunodeficiency virus type 1 reverse transcriptase

A recombinant simian immunodeficiency virus (SIV) derived from strain 239 (SIVmac239) with reverse transcriptase (RT) sequences from human immunodeficiency virus type 1 (HIV-1) strain HXB2 was severely impaired for replication. Detectable p27(Gag) levels were not observed until day 65 and peak p27(Gag) levels were not reached until day 75 after transfection of CEMx174 cells with the recombinant DNA. Sequences from the latter time point did not contain amino acid substitutions in HIV-1 RT; however, a single nucleotide substitution (thymine to cytosine) was found at position eight of the SIV primer binding site. We engineered an RT/SHIV genome with the thymine-to-cytosine substitution, called RT/SHIV/TC, and observed dramatically faster replication kinetics than were observed with the parental RT/SHIV from which this variant was derived. RT/SHIV/TC provides an improved system for study of the impact of drug resistance mutations in HIV-1 RT in a relevant animal model.