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Background: Atazanavir (ATV) has demonstrated high efficacy and safety in both treatment-naïve and treatment-experienced patients. Some comparative data are available on the durability of ritonavir-boosted (ATV/r) and unboosted formulations, but there are no data on clinicians' motivations for choosing one or another in everyday practice. The aim of this study was to evaluate the long-term efficacy of boosted and unboosted ATV in a cohort of treatment-experienced patients., Methods: All patients included in the study were enrolled in an observational cohort within the Surveillance Cohort Long-Term Toxicity Antiretrovirals (SCOLTA) Project. Data on CD4 cell count, HIV viral load, metabolic parameters and adverse events of grade 3-4 are collected through an on-line system every six months. The duration of treatment with ATV was evaluated using the Kaplan-Meier curve and boosted and unboosted regimens were compared using the log-rank test., Results: A total of 509 patients starting ATV as a component of their antiretroviral therapy were enrolled in the SCOLTA Project at the time of the study. Boosted ATV was received by 379 patients (74.5%) while 130 (25.5%) were treated with the unboosted formulation. The last therapeutic regimen did not influence the choice of ATV formulation. The mean observational time was 23.9 months. At the end of follow-up, 58.5% of patients on unboosted ATV and 58.1% of patients on ATV/r continued the treatment and no statistically significant differences were observed for ATV durability between the formulations or among the single causes of therapy interruption., Conclusions: Our results suggest that, in unselected clinical settings, ATV-containing antiretroviral therapy is durable and safe in both its formulations.

This study was undertaken to establish whether a change in the perineuronal satellite cell number contributes to the age-related reduction of the volume ratio between the perineuronal glial sheaths and their associated nerve cell bodies, observed to occur in rabbit spinal ganglia. The volumes of the nerve cell bodies and the numbers of the related satellite cell nuclei were estimated on serial semithin sections from young adult and old rabbits. As satellite cells are mononucleate, the number of the nuclei corresponds to that of these cells. The satellite cell sheaths in both age groups were also examined under the electron microscope. The mean number of satellite cells was significantly smaller in the aged animals than in the young adults although the mean volume of the nerve cell bodies was significantly larger in the former. Cytoplasmic vacuoles, invaginations of the connective tissue and autophagic vacuoles were more frequent in the old rabbits. Satellite cells with pyknotic nuclei and remnants of degenerated satellite cells were only found in aged animals, although rather rarely. The decrease in the satellite cell number is one of the mechanisms by which the age-related reduction of the volume ratio between the perineuronal glial sheaths and their associated nerve cell bodies takes place. The decrease in the satellite cell number seems to occur, at least in part, through cell degeneration. However, other mechanisms (e.g., detachment of satellite cells from the perineuronal sheaths) cannot be excluded. Since satellite cells play a role in neuronal support, the significant decrease in their number probably has negative consequences for neuronal activity.