Investigating the development and evolution of drug resistance in the HIV-1 pol gene

The prognosis of those infected with HIV-1 has improved significantly since the introduction of highly active antiretroviral therapy (HAART). This has led to complete suppression of HIV-1 replication and reduction of viraemia to undetectable levels. Initially HAART comprised of three classes of drugs, namely nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs) and protease inhibitors (PIs), which target two important viral enzymes. Until recently, patients developing highly drug-resistant HIV-1 have had limited therapy options. This has changed in the last few years with the development and approval for use of second-generation NNRTIs and PIs, and three new classes of drugs including integrase strand transfer inhibitors (INSTIs). This means that patients undergoing INSTI-containing salvage therapy are taking drugs targeting all three HIV-1 pol genes; protease (PR), RT and IN. However, little data is available on the evolution, interaction and linkage of drug resistance mutations throughout the pol gene. In this study, we developed a single genome sequencing assay of the full-length HIV-1 pol gene and used it to investigate the development and linkage of drug resistance mutations in sequential samples from two patients failing INSTI-containing salvage therapy. Different phylogenetic methods were used to explore the evolution and dynamics of drug resistance mutations in the full-length HIV-1 pol gene. Furthermore, we examined the effect of co-evolved PR and RT on the susceptibility of patient-derived viruses to INSTIs and viral replicative fitness. Our data indicate that the development of drug resistance mutations in IN is complex and is a fine balance between attaining high levels of drug resistance and decent replicative fitness. This is to a degree influenced by mutations in other regions of the HIV-1 pol gene. Taken together, the data suggests that larger regions of patient-derived HIV-1 genome should be examined in order to get a good understanding of HIV-1 drug susceptibility

Using Supervised Principal Components Analysis to Assess Multiple Pollutant Effects

BACKGROUND: Many investigations of the adverse health effects of multiple air pollutants analyze the time series involved by simultaneously entering the multiple pollutants into a Poisson log-linear model. This method can yield unstable parameter estimates when the pollutants involved suffer high intercorrelation; therefore, traditional approaches to dealing with multicollinearity, such as principal component analysis (PCA), have been promoted in this context. OBJECTIVES: A characteristic of PCA is that its construction does not consider the relationship between the covariates and the adverse health outcomes. A refined version of PCA, supervised principal components analysis (SPCA), is proposed that specifically addresses this issue. METHODS: Models controlling for long-term trends and weather effects were used in conjunction with each SPCA and PCA to estimate the association between multiple air pollutants and mortality for U.S. cities. The methods were compared further via a simulation study. RESULTS: Simulation studies demonstrated that SPCA, unlike PCA, was successful in identifying the correct subset of multiple pollutants associated with mortality. Because of this property, SPCA and PCA returned different estimates for the relationship between air pollution and mortality. CONCLUSIONS: Although a number of methods for assessing the effects of multiple pollutants have been proposed, such methods can falter in the presence of high correlation among pollutants. Both PCA and SPCA address this issue. By allowing the exclusion of pollutants that are not associated with the adverse health outcomes from the mixture of pollutants selected, SPCA offers a critical improvement over PCA

P17-26. Effective design of T-cell driven vaccines applied to the GAIA HIV vaccine: advances in vaccine design based on current preclinical success

Poster Presentatio

Tuberculosis incidence correlates with sunshine : an ecological 28-year time series study

Birmingham is the largest UK city after London, and central Birmingham has an annual tuberculosis incidence of 80 per 100,000. We examined seasonality and sunlight as drivers of tuberculosis incidence. Hours of sunshine are seasonal, sunshine exposure is necessary for the production of vitamin D by the body and vitamin D plays a role in the host response to tuberculosis. Methods: We performed an ecological study that examined tuberculosis incidence in Birmingham from Dec 1981 to Nov 2009, using publicly-available data from statutory tuberculosis notifications, and related this to the seasons and hours of sunshine (UK Meteorological Office data) using unmeasured component models. Results: There were 9,739 tuberculosis cases over the study period. There was strong evidence for seasonality, with notifications being 24.1% higher in summer than winter (p<0.001). Winter dips in sunshine correlated with peaks in tuberculosis incidence six months later (4.7% increase in incidence for each 100 hours decrease in sunshine, p<0.001). Discussion and Conclusion: A potential mechanism for these associations includes decreased vitamin D levels with consequent impaired host defence arising from reduced sunshine exposure in winter. This is the longest time series of any published study and our use of statutory notifications means this data is essentially complete. We cannot, however, exclude the possibility that another factor closely correlated with the seasons, other than sunshine, is responsible. Furthermore, exposure to sunlight depends not only on total hours of sunshine but also on multiple individual factors. Our results should therefore be considered hypothesis-generating. Confirmation of a potential causal relationship between winter vitamin D deficiency and summer peaks in tuberculosis incidence would require a randomized-controlled trial of the effect of vitamin D supplementation on future tuberculosis incidence

Europium doping of zincblende GaN by ion implantation

Eu was implanted into high quality cubic (zincblende) GaN (ZB-GaN) layers grown by molecular beam epitaxy. Detailed structural characterization before and after implantation was performed by x-ray diffraction (XRD) and Rutherford backscattering/channeling spectrometry. A low concentration ( direction, while a Ga substitutional site is observed for W-GaN:Eu. The implantation damage in ZB-GaN:Eu could partly be removed by thermal annealing, but an increase in the wurtzite phase fraction was observed at the same time. Cathodoluminescence, photoluminescence (PL), and PL excitation spectroscopy revealed several emission lines which can be attributed to distinct Eu-related optical centers in ZB-GaN and W-GaN inclusions

Biopsychosocial correlates of persistent postsurgical pain in women with endometriosis

ObjectiveTo examine pain and biopsychosocial correlates over time for women with persistent postsurgical pain after surgery for endometriosis.MethodsCrossâ sectional study of women who underwent any endometriosis surgery between 2003 and 2006. Following surgery, patients completed validated questionnaires (Shortâ Form McGill Pain Questionnaire, 12â item Shortâ Form Health Survey, Beck Depression Inventory, Coping Strategies Questionnaire catastrophizing subscale). The primary outcome was pelvic pain intensity, measured by the McGill total pain score. Bivariate comparisons between each potential predictor and pain intensity were performed using the Ï 2 and t tests, 1â way analysis of variance, and simple linear regression.ResultsIn total, 79 completed the questionnaires and were included in the present analysis. The McGill affective pain score was negatively correlated with age (βâ coefficient â 0.12, P = 0.002) and positively correlated with catastrophization (βâ coefficient 0.66, P = 0.01). Women with a history of dyspareunia scored significantly higher on the McGill total pain score (P < 0.001); there was no association between pain intensity and endometriosis severity.ConclusionYounger age and catastrophization are correlated with persistent pain following surgery for endometriosis. The severity of endometriosis does not predict persistent pain. Further evaluation of psychosocial factors may identify patients who are least likely to benefit from surgeries for endometriosisâ associated pelvic pain.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135478/1/ijgo169.pd

Enhanced production of oxidised mercury over the tropical Pacific Ocean: A key missing oxidation pathway

Mercury is a contaminant of global concern. It is transported in the atmosphere primarily as gaseous elemental mercury, but its reactivity and deposition to the surface environment, through which it enters the aquatic food chain, is greatly enhanced following oxidation. Measurements and modelling studies of oxidised mercury in the polar to sub-tropical marine boundary layer (MBL) have suggested that photolytically produced bromine atoms are the primary oxidant of mercury. We report year-round measurements of elemental and oxidised mercury, along with ozone, halogen oxides (IO and BrO) and nitrogen oxides (NO2), in the MBL over the Galápagos Islands in the equatorial Pacific. Elemental mercury concentration remained low throughout the year, while higher than expected levels of oxidised mercury occurred around midday. Our results show that the production of oxidised mercury in the tropical MBL cannot be accounted for by bromine oxidation only, or by the inclusion of ozone and hydroxyl. As a two-step oxidation mechanism, where the HgBr intermediate is further oxidised to Hg(II), depends critically on the stability of HgBr, an additional oxidant is needed to react with HgBr to explain more than 50% of the observed oxidised mercury. Based on best available thermodynamic data, we show that atomic iodine, NO2, or HO2 could all play the potential role of the missing oxidant, though their relative importance cannot be determined explicitly at this time due to the uncertainties associated with mercury oxidation kinetics. We conclude that the key pathway that significantly enhances atmospheric mercury oxidation and deposition to the tropical oceans is missing from the current understanding of atmospheric mercury oxidation