Performance of influenza rapid antigen testing in influenza in emergency department patients.

BACKGROUND: The use of rapid antigen tests to triage specimens for polymerase chain reaction (PCR) testing from emergency department patients with influenza-like illness during surveillance for novel influenza viruses has been suggested. OBJECTIVE: To measure the observed sensitivity and specificity for a widely used rapid antigen test (Binax) using a PCR-based assay (Medical Diagnostic Laboratories). METHODS: Nasopharyngeal samples were taken with flocked swabs (Copan Diagnostics) from patients presenting to the emergency department of a community hospital. Samples were analysed using a rapid antigen and a PCR-based test. PCR testing was used as the criterion reference. Sensitivity and specificity were calculated for influenza and influenza A. Positive predictive values were calculated over a range of possible prevalence. RESULTS: Samples from 566 unique patients were tested using both methods. Sensitivity was 69.1% (95% CI 58.9% to 78.1%) and specificity was 97.7% (95% CI 95.8% to 98.8%) for the detection of any influenza and 75.3% (95% CI 64.7% to 84.0%) and 97.8% (95% CI 95.9% to 98.9%), respectively, for influenza A only. The resultant positive predictive value ranges from 23% to 77% when the prevalence ranges from 1% to 10%. CONCLUSION: When planning early outbreak surveillance, provision of adequate PCR testing capacity rather than triaging specimens using rapid antigen testing for influenza is advisable.

Inhibition of human immunodeficiency virus (HIV-1) replication in SupT1 cells transduced with an HIV-1 LTR-driven PKR cDNA construct.

Current strategies against the human immunodeficiency virus type 1 (HIV-1), including nucleoside analogues and protease inhibitors, have limited effectiveness as shown by the evolution of resistant retroviral strains and the presence of latent HIV-1 reservoirs. Therefore, it is necessary to look beyond anti-retroviral strategies and to rely on the body's immune system to inhibit HIV-1 replication. In this study, we approach the inhibition of HIV-1 replication by upregulation of the antiviral pathway that is natural to mammalian cells. Vectors were constructed which were capable of transferring the antiviral enzyme, p68 kinase (PKR), into target SupT1 lymphoblastoid cells under HIV-1 LTR transcriptional regulation via a retroviral-mediated shuttle system. We report a significant inhibition of HIV-1 replication in HIV-1 LTR-PKR cDNA transduced clones (105-10 : 239 and 106-4 : 560) expressing different PKR levels as measured by inhibition of HIV-1 induced syncytia formation and HIV-1 reverse transcriptase activity. Whereas the expression of PKR in parental vector transduced clone (N2-20P) is down-regulated 48 h after HIV-1 infection, the two transduced clones (one with PKR in the forward orientation and one in the reverse orientation) demonstrate increased PKR expression through 96 h post-infection, concomitant with an increase in eIF-2alpha phosphorylation and an increase in NF-kappaB activity at 72 h postinfection. These results demonstrate that the overexpression of PKR can inhibit HIV-1 replication and confirm the involvement of PKR in the IFN-associated antiviral pathway against HIV-1 infection. Finally, the treatment of the transduced clone 106-4 : 560 with AZT resulted in complete inhibition of HIV-1 replication.

Synthesis and biological activity of 2',5'-oligoadenylate trimers containing 5'-terminal 5'-amino-5'-deoxy- and 5'-amino-3',5'-dideoxyadenosine derivatives.

Some new 2',5'-oligonucleotide trimers containing 5'-terminal 5'-amino-5'-deoxy- and 5'-amino-3',5'-dideoxyadenosine derivatives have been synthesized. Some of the trimers showed biological inhibitions of HIV-1 reverse transcriptase (RT), HIV-1 induced syncytia formation and PCR amplification.

Biochemical evidence for a novel low molecular weight 2-5A-dependent RNase L in chronic fatigue syndrome.

Previous studies from this laboratory have demonstrated a statistically significant dysregulation in several key components of the 2',5'-oligoadenylate (2-5A) synthetase/RNase L and PKR antiviral pathways in chronic fatigue syndrome (CFS) (Suhadolnik et al. Clin Infect Dis 18, S96-104, 1994; Suhadolnik et al. In Vivo 8, 599-604, 1994). Two methodologies have been developed to further examine the upregulated RNase L activity in CFS. First, photoaffinity labeling of extracts of peripheral blood mononuclear cells (PBMC) with the azido 2-5A photoaffinity probe, [32P]pApAp(8-azidoA), followed by immunoprecipitation with a polyclonal antibody against recombinant, human 80-kDa RNase L and analysis under denaturing conditions. A subset of individuals with CFS was identified with only one 2-5A binding protein at 37 kDa, whereas in extracts of PBMC from a second subset of CFS PBMC and from healthy controls, photolabeled/immunoreactive 2-5A binding proteins were detected at 80, 42, and 37 kDa. Second, analytic gel permeation HPLC was completed under native conditions. Extracts of healthy control PBMC revealed 2-5A binding and 2-5A-dependent RNase L enzyme activity at 80 and 42 kDa as determined by hydrolysis of poly(U)-3'-[32P]pCp. A subset of CFS PBMC contained 2-5A binding proteins with 2-5A-dependent RNase L enzyme activity at 80, 42, and 30 kDa. However, a second subset of CFS PBMC contained 2-5A binding and 2-5A-dependent RNase L enzyme activity only at 30 kDa. Evidence is provided indicating that the RNase L enzyme dysfunction in CFS is more complex than previously reported.