The concordance of the limiting antigen and the Bio-Rad avidity assays in persons from Estonia infected mainly with HIV-1 CRF06_cpx

BACKGROUND: Serological assays to determine HIV incidence have contributed to estimates of HIV incidence, monitoring of HIV spread, and evaluation of prevention strategies. Two frequently used incidence assays are the Sedia HIV-1 LAg-Avidity EIA (LAg) and the Bio-Rad avidity incidence (BRAI) assays with a mean duration of recent infection (MDRI) of 130 and 240 days for subtype B infections, respectively. Little is known about how these assays perform with recombinant HIV-1 strains. We evaluated the concordance of these assays in a population infected mainly with HIV-1 CRF06_cpx. MATERIAL/METHODS: Remnant serum samples (n = 288) collected from confirmed, newly-diagnosed HIV-positive persons from Estonia in 2013 were tested. Demographic and clinical data were extracted from clinical databases. LAg was performed according to the manufacturer’s protocol and BRAI testing was done using a validated protocol. Samples with LAg-pending or BRAI-invalid results were reclassified as recent if they were from persons with viral loads <1000 copies/mL or were reclassified as long-term if presenting with AIDS. RESULTS: In total 325 new HIV infections were diagnosed in 2013 in Estonia. Of those 276 persons were tested with both LAg and BRAI. Using assay results only, the recency rate was 44% and 70% by LAg and BRAI, respectively. The majority of samples (92%) recent by LAg were recent by BRAI. Similarly, 89% of samples long-term by BRAI were long-term by LAg. After clinical information was included in the analysis, the recency rate was 44% and 62% for LAg and BRAI, respectively. The majority of samples (86%) recent by LAg were recent by BRAI and 91% of long-term infections by BRAI were long-term by LAg. CONCLUSIONS: Comparison of LAg and BRAI results in this mostly CRF06_cpx-infected population showed good concordance for incidence classification. Our finding of a higher recency rate with BRAI in this population is likely related to the longer MDRI for this assay

OBSERVATION OF THE 0-1 ROTATIONAL TRANSITION IN PURE AND SEEDED OCS-BEAMS WITH A MICROWAVE STARK SPECTROMETER

Author Institution:The 0-1 rotational transition in pure and Argon-seeded OCS-beams has been observed using a groove guide Stark spectrometer, coupled to a supersonic beam source. The width of the Gaussian lineshapes was found to be 2.2 kHz for an Argon-seeded beam and 4 kHz for a pure beam, showing Che difference in translational temperature for seeded and pure beams, respectively. From the direction of the Doppler shift, whose absolute value is a measure of the average beam velocity, it is concluded that the observed signals appear in emission rather than in absorption

A Theoretical study on the dissociation reaction of dioxirane: H2CO2 to H2 + CO2

An ab initio Cl Calculation of the reaction pathway of the unimolecular dissociation of dioxirane to carbon dioxide and molecular hydrogen has been carried out. The calculated adiabatic potential surface indicates that the separation of H2 is preceded by the predominant ring-opening process. The minimum-energy pathway the transition state, diradical state and saddle point have been determined

Non adiabatic interactions in the symmetric ring opening process of dioxirane

The first two electronic states of 1A1 symmetry in the symmetric ring opening unimolecular reaction, leading from the dioxirane molecule to the dioxymethane diradical, are investigated by ab initio CI calculations. Due to the presence of a strong non-adiabatic interaction between the ground state and the first excited state in the vicinity of the transition state, the diabatic representation is adopted. The nuclear motion problem for the ring opening is solved with the diabatic potentials. The resulting wavefunctions are good approximations to the vibronic state which scarcely mix the two diabatic electronic states. It is therefore argued that the formation of the diradical by excitation of the OCO bending of dioxirane is relatively unlikely

The significance of pre-existing minority Y181C mutations on virological failure of NNRTI-based, first-line antiretroviral therapy

Background: Reduced re'nal function has been reported with tenofovir disoproxil fumarate (TDF). It is not clear whether TDF co-administered with a boosted protease inhibitor (PI) leads to a greater decline in renal function than TDF co-administered with a non-nucleoside reverse transcriptase inhibitor (NNRTI).Methods: We selected ail antiretroviral therapy-naive patients in the Swiss HIV Cohort Study (SHCS) with calibrated or corrected serum creatinine measurements starting antiretroviral therapy with TDF and either efavirenz (EFV) or the ritonavir-boosted PIs, lopinavir (LPV/r) or atazanavir (ATV/r). As a measure of renal function, we used the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation to estimate the glomerular filtration rate (eGFR). We calculated the difference in eGFR over time between two therapies using a marginal model for repeated measures. In weighted analyses, observations were weighted by the product of their point of treatment and censoring weights to adjust for differences both in the sort of patients starting each therapy and in the sort of patients remaining on each therapy over time.Results: By March 2011, 940 patients with at least one creatinine measurement on a first therapy with either TDF and EFV (n=484), TDF and LPVlr (n=269) or TDF and ATV/r (n=187) had been followed for a median of 1. 7, 1.2 and 1.3 years, respectively. Table 1 shows the difference in average estimated GFR (eGFR) over time since starting cART for two marginal models. The first model was not adjusted for potential confounders; the second mode! used weights to adjust for confounders. The results suggest a greater decline in renal function during the first 6 months if TDF is used with a PI rather than with an NNRTI, but no further difference between these therapies after the first 6 months. TDF and ATV/r may lead to a greater decline in the first 6 months than TDF and LPVlr.Conclusions: TDF co-administered with a boosted PI leads to a greater de cline in renal function over the first 6 months of therapy than TDF co-administered with an NNRTI; this decline may be worse with ATV/r than with LPV/r