Éditeur(s) : Paris : chez Pillet aîné
Siècle(s) traité(s) : 19
Droits : Domaine public
Provenance : Collectivité territoriale de Martinique. Bibliothèque Schoelcher
Permalien : http://www.manioc.org/patrimon/SCH13172
SCH13172

Éditeur(s) : HAL CCSD Lippincott, Williams & Wilkins
Résumé : International audience
The aim of the study was to investigate the impact of first-line combined antiretroviral therapy (cART) regimen on the course of CD8 + T-cell counts in human immunodeficiency virus (HIV)-infected patients. A retrospective observational study conducted on the French DAT'AIDS Cohort of HIV-infected patients. We selected 605 patients initiating a first-line cART between 2002 and 2009, and which achieved a sustained undetectable HIV plasma viral load (pVL) for at least 12 months without cART modification. The evolution of CD8 + T-cell counts according to cART regimen was assessed. CD8 + T-cell counts were assessed in 572 patients treated with 2NRTIs+1PI/r (n= 297), 2NRTIs+1NNRTI (n= 207) and 3NRTIs (n= 68). In multivariate analysis, after 12 months of follow-up, the 3NRTIs regimen was associated with a significantly smaller decrease of CD8 + T-cell count compared with NNRTI-containing regimens (–10.2 cells/mL in 3NRTIs vs –105.1 cells/mL; P=0.02) but not compared with PI-containing regimens (10.2 vs –60.9 cells/mL; P=0.21). After 24 months, the 3NRTIs regimen was associated with a smaller decrease of CD8 + T-cell count and % compared with PI/r-and NNRTI-containing regimens (0.2 in 3NRTIs vs –9.9 with PI/r-regimens, P=0.001, and vs –11.1 with NNRTI-regimens, p < 0.0001). A focus analysis on 11 patients treated with an INSTI-containing cART regimen during the study period showed after 12 months of follow-up, a median decrease of CD8 + T-cell count of –155 [inter quartile range: –302; –22] cells/mL. Our data highlight the fact that cART regimens have differential effects on CD8 pool down regulation. Abbreviations: cART = combined antiretroviral therapy, HIV = human immunodeficiency virus, INSTI = integrase strand transfer inhibitor, NNRTI = non-nucleotide reverse transcriptase inhibitor, NRTI = nucleotide reverse transcriptase inhibitor, PI/r = Ritonavir-boosted protease inhibitor, pVL = plasma viral load.
ISSN: 0025-7974

inserm-01408002
http://www.hal.inserm.fr/inserm-01408002
http://www.hal.inserm.fr/inserm-01408002/document
http://www.hal.inserm.fr/inserm-01408002/file/2016%2C%20Poizot-Martin%20-%20First-line%20cART%20regimen%20impacts%20the%20course%20of%20CD8%2B%20T-cell%20counts%20in%20HIV-infected%20patients.pdf
DOI : 10.1097/MD.0000000000005087

Éditeur(s) : HAL CCSD Elsevier
Résumé : Vegetation phenology is the study of the timing of seasonal events that are considered to be the result of adaptive responses to climate variations on short and long time scales. In the field of remote sensing of vegetation phenology, phenological metrics are derived from time series of optical data. For that purpose, considerable effort has been specifically focused on developing noise reduction and cloud-contaminated data removal techniques to improve the quality of remotely-sensed time series. Comparative studies between time series composed of satellite data acquired under clear and cloudy conditions and from radiometric data obtained with high accuracy from ground-based measurements constitute a direct and effective way to assess the operational use and limitations of remote sensing for predicting the main plant phenological events. In the present paper, we sought to explicitly evaluate the potential use of MODerate resolution Imaging Spectroradiometer (MODIS) remote sensing data for monitoring the seasonal dynamics of different types of vegetation cover that are representative of the major terrestrial biomes, including temperate deciduous forests, evergreen forests, African savannah, and crops. After cloud screening and filtering, we compared the temporal patterns and phenological metrics derived from in situ NDVI time series and from MODIS daily and 16-composite products. We also evaluated the effects of residual noise and the influence of data gaps in MODIS NDVI time series on the identification of the most relevant metrics for vegetation phenology monitoring. The results show that the inflexion points of a model fitted to a MODIS NDVI time series allow accurate estimates of the onset of greenness in the spring and the onset of yellowing in the autumn in deciduous forests (RMSE <= one week). Phenological metrics identical to those provided with the MODIS Global Vegetation Phenology product (MDC12Q2) are less robust to data gaps, and they can be subject to large biases of approximately two weeks or more during the autumn phenological transitions. In the evergreen forests, in situ NDVI time series describe the phenology with high fidelity despite small temporal changes in the canopy foliage. However, MODIS is unable to provide consistent phenological patterns. In crops and savannah, MODIS NDVI time series reproduce the general temporal patterns of phenology, but significant discrepancies appear between MODIS and ground-based NDVI time series during very localized periods of time depending on the weather conditions and spatial heterogeneity within the MODIS pixel. In the rainforest, the temporal pattern exhibited by a MODIS 16-day composite NDVI time series is more likely due to a pattern of noise in the NDVI data structure according to both rainy and dry seasons rather than to phenological changes. More investigations are needed, but in all cases, this result leads us to conclude that MODIS time series in tropical rainforests should be interpreted with great caution. (C) 2013 Elsevier Inc. All rights reserved.
ISSN: 0034-4257

hal-01032407
https://hal.archives-ouvertes.fr/hal-01032407
DOI : 10.1016/j.rse.2013.01.010