RESUMO
The New Horizons mission has provided resolved measurements of Pluto's moons Styx, Nix, Kerberos, and Hydra. All four are small, with equivalent spherical diameters of ~40 kilometers for Nix and Hydra and ~10 kilometers for Styx and Kerberos. They are also highly elongated, with maximum to minimum axis ratios of ~2. All four moons have high albedos (~50 to 90%) suggestive of a water-ice surface composition. Crater densities on Nix and Hydra imply surface ages of at least 4 billion years. The small moons rotate much faster than synchronous, with rotational poles clustered nearly orthogonal to the common pole directions of Pluto and Charon. These results reinforce the hypothesis that the small moons formed in the aftermath of a collision that produced the Pluto-Charon binary.
RESUMO
BACKGROUND: The immunological and clinical benefits of structured treatment interruptions (STIs) during primary HIV-1 infection remain largely unclear. PATIENTS AND METHODS: Eight patients identified during primary HIV-1 infection were immediately treated with HAART and underwent subsequent STIs after reaching complete viral suppression of HIV-RNA in peripheral plasma. HAART was re-initiated if either HIV-1 RNA >5000 copies/ml, CD4-cells <200 cells/microl or symptomatic HIV-1 disease was observed. RESULTS: After treatment discontinuation, four of eight patients were able to persistently control HIV-1 viremia below 5000 copies/ml until the last time point of follow-up (median 3 years). CD4-cell counts were within the interquartile range of untreated individuals compared to historical reference data from the MACS cohort. In the remaining study subjects persistent virological control was not reached despite repeated STIs. Moreover, compared to the MACS cohort repetitive virological failures during STIs appeared to induce an accelerated decline of CD4-cells. CONCLUSION: Spontaneous HIV-1 control after treated primary HIV-1 infection was possible in four out of eight individuals, however, if STIs after treated primary infection ameliorate the overall HIV-1 disease progression remains unknown. In the absence of viral control, repetitive viral exposure during STIs might be associated with accelerated decline of CD4-cell counts.
