Anti-poliovirus activity of protease inhibitor AG-7404, and assessment of in vitro activity in combination with antiviral capsid inhibitor compounds.

The National Research Council has recommended that at least one, preferably two, polio antiviral drugs be developed as a supplement to the tools currently available for control of polio outbreaks post-eradication. The primary application of such drugs is expected to be the resolution of chronic poliovirus excretion in persons with primary immunodeficiency disorders. We have assessed the in vitro activity of AG-7404 (also known as "compound 1"), an inhibitor of picornaviral 3C protease, against a large panel of programmatically important poliovirus strains and its activity in combination with two poliovirus capsid inhibitors, V-073 and BTA798. AG-7404 was active against all viruses in this panel, with EC50 values ranging from 0.080 to 0.674 µM. Similarly, BTA798 was active against all viruses in this panel, with EC50 values ranging from 0.003 to 0.591µM. By comparison, values for V-073 were 0.003-0.126 µM. BTA798 was active against V-073-resistant variants with an alanine to valine change in VP3 at position 24. However, BTA798 was inactive against the V-073-resistant strains with amino acid substitutions at VP1 amino acids 194 (equivalent to 192 in type 3) and 236. As expected from its different mechanism of action, AG-7404 was fully active against all V-073-resistant variants, with EC50 values ranging from 0.218 to 0.819 µM, compared to values of 0.202-0.407 µM for the V-073-susceptible parental strains. In vitro drug combination experiments demonstrated synergy between AG-7404 and either V-073 or BTA798, whereas the combination of the two capsid inhibitors acted additively.

Health risk assessment of PCDD/F emissions from municipal solid waste incinerators (MSWIs) in China.

The objectives of this study were to determine the environmental impacts of polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran (PCDD/Fs) emitted from two typical municipal solid-waste incinerators (MSWIs), named M and L, in China. The main differences between the two MSWIs relate to incineration technologies, treatment capacities, emission standards and meteorological conditions. The distribution of PCDD/Fs in the surrounding ambient air and soils of the MWSIs were monitored and compared. In addition, air dispersion models and health risk assessments were combined to determine the behaviour and transport of PCDD/Fs. The results indicated that higher PCDD/F emission levels resulted in higher concentrations in the surrounding environment. The average PCDD/F levels emitted from the M MSWI was about seven times higher than those emitted from the L MSWI and about 10 times and 2 times higher in air and soils, respectively. The simulation results were similar to the trend of the monitored results. Both the observed and the simulation results suggested that the atmospheric pollution by PCDD/F surrounding the M MSWI was relatively serious; the environmental impact of the L MSWI was not significant.