59 research outputs found
Spondylodiscite à Aspergillus fumigatus après discectomie d'évolution favorable sous itraconazole
No full textPrevalence and impact of GBV-C, SEN-V and HBV occult infections in HIV–HCV co-infected patients on HCV therapy
No full textBackground/AimsIt has been suggested that, in HIV–HCV co-infected patients, co-infections with other viruses may affect the response to HCV therapy. We aimed to assess the prevalence of GBV-C, SEN-V and occult HBV infections, their impact on HCV and HIV infections and on the response to HCV therapy in HIV–HCV co-infected patients. Methods Three-hundred and sixty eight patients were tested before starting interferon–ribavirin for the presence of occult hepatitis B DNA, GBV-C RNA and SEN-V DNA by using real time PCR. Clinical, immunological, virological, histological characteristics and response to HCV therapy were compared according to the presence or not of each viral co-infection. Results HBV DNA, GBV-C RNA and SEN-V DNA were found in 5 (1.4%, CI95%: 0.2–2.4%), 104 (29.9%, CI95%: 25.1–34.7%) and 209 patients (57.9%, CI95%: 52.8–63.0%), respectively. GBV-C positive patients had significantly higher CD4 count at baseline, during and after HCV therapy, even after stratification on antiretroviral treatment. No other significant difference was observed according to the presence or not of GBV-C or SEN-V co-infection, in particular regarding virological responses to HCV combination therapy. Conclusions There is no reason to withhold HCV therapy in HIV infected patients who have access to HAART, because of occult HBV, GBV-C or SEN-V co-infections
Assessment of liver fibrosis and associated risk factors in HIV-infected individuals using transient elastography and serum biomarkers
No full textBackground: Liver fibrosis in human immunodeficiency virus (HIV)-infected individuals is mostly attributable to co-infection with hepatitis B or C. The impact of other risk factors, including prolonged exposure to combined antiretroviral therapy (cART) is poorly understood. Our aim was to determine the prevalence of liver fibrosis and associated risk factors in HIV-infected individuals based on non-invasive fibrosis assessment using transient elastography (TE) and serum biomarkers (Fibrotest [FT]).
Methods: In 202 consecutive HIV-infected individuals (159 men; mean age 47 ± 9 years; 35 with hepatitis-C-virus [HCV] co-infection), TE and FT were performed. Repeat TE examinations were conducted 1 and 2 years after study inclusion.
Results: Significant liver fibrosis was present in 16% and 29% of patients, respectively, when assessed by TE (≥ 7.1 kPa) and FT (> 0.48). A combination of TE and FT predicted significant fibrosis in 8% of all patients (31% in HIV/HCV co-infected and 3% in HIV mono-infected individuals). Chronic ALT, AST and γ-GT elevation was present in 29%, 20% and 51% of all cART-exposed patients and in 19%, 8% and 45.5% of HIV mono-infected individuals. Overall, factors independently associated with significant fibrosis as assessed by TE (OR, 95% CI) were co-infection with HCV (7.29, 1.95-27.34), chronic AST (6.58, 1.30-33.25) and γ-GT (5.17, 1.56-17.08) elevation and time on dideoxynucleoside therapy (1.01, 1.00-1.02). In 68 HIV mono-infected individuals who had repeat TE examinations, TE values did not differ significantly during a median follow-up time of 24 months (median intra-patient changes at last TE examination relative to baseline: -0.2 kPa, p = 0.20).
Conclusions: Chronic elevation of liver enzymes was observed in up to 45.5% of HIV mono-infected patients on cART. However, only a small subset had significant fibrosis as predicted by TE and FT. There was no evidence for fibrosis progression during follow-up TE examinations
Stochastic processes and crop types shape weed community assembly in arable fields
No full textInternational audienceAimsIn agro-ecosystems, crop types, i.e., the crop species and its associated agricultural practices, have been shown to influence the taxonomic as well as functional composition of weed communities. However, the processes underlying weed community assembly within a crop type are poorly understood, especially regarding the contributions of local factors and stochastic processes. In this study, we investigate the effects of the crop type in shaping local weed communities.LocationLTER Zone Atelier Plaine et Val de Sèvre, an intensive cereal system in western France.MethodsWe selected 105 fields of five crop types and investigated the functional structure of weed communities for those traits that define the Leaf–Height–Seed (L-H-S) strategy as well as phenological traits. We compared the observed trait distribution to trait distributions expected under random assembly. The trait distributions were described by the range, the community-weighted mean and the dispersion of each trait, and simulated communities were generated with a null model approach that randomizes the ‘species × traits’ matrix to maintain equiprobable the occurrence of each trait combination. The relationship between trait values and species abundance within each community was investigated using Kendall rank correlation tests.ResultsOur results showed that, in ca. 90% of the fields, the functional diversity of weed communities did not differ from what would be expected under random assembly. Departures from random expectations essentially resulted from shifts in weighted mean values for phenological traits. Weed communities of sunflower, maize and spring pea had later onsets of emergence and flowering than randomly expected. Communities of winter wheat had smaller species and earlier onset of flowering, and communities from oilseed rape had a larger duration of the emergence period and earlier onset of flowering. In addition, we found a positive significant relationship between species abundance and trait values for phenology for spring pea, sunflower and maize, suggesting that species with a later onset of emergence and flowering period have higher performance in these weed communities.ConclusionsAt landscape scale, weed communities generally showed patterns of functional diversity in accordance with those expected under random community assembly, except for phenological traits in spring and summer crops, where patterns were rather consistent with environmental filtering
Isolation rooms for highly infectious diseases: an inventory of capabilities in European countries
No full textIsolation of patients with highly infectious diseases (HIDs) in hospital rooms with adequate technical facilities is essential to reduce the risk of spreading disease. The European Network for Infectious Diseases (EUNID), a project co-funded by European Commission and involving 16 European Union member states, performed an inventory of high level isolation rooms (HIRs, hospital rooms with negative pressure and anteroom). In participating countries, HIRs are available in at least 211 hospitals, with at least 1789 hospital beds. The adequacy of this number is not known and will depend on prevailing circumstances. Sporadic HID cases can be managed in the available HIRs. HIRs could also have a role in the initial phases of an influenza pandemic. However, large outbreaks due to natural or to bioterrorist events will need management strategies involving healthcare facilities other than HIRs. © 2009 The Hospital Infection Society
Crop competition in winter wheat has a higher potential than farming practices to regulate weeds
No full textInternational audienceManagement of biotic interactions has been recognized as a potential substitute for costly agrochemical inputs. Competition is one of the most important biotic interactions known to regulate populations and govern species assemblages. However, although theoretical and empirical work has been produced on competition, in situ experimental evidence is much scantier, mainly because of the difficulty of manipulating competition in the field. Arable weeds offer an outstanding opportunity to meet this challenge, because of the relative ease of in situ experimental manipulation and because of the urgent need to find sustainable weed management strategies. Here, we assess the importance of crop competition and two main conventional farming practices (N fertilizer and weed control) on weed species richness, abundance, and biomass. We set up an experiment with a design with two factors, presence/absence of crops and presence/absence of N fertilizer and weed control, in working farm fields with winter cereals as the target crop. We found that the crop competition reduced weed biomass production by almost 65%, as a result of the crop's competitive advantage from its greater ability to take up N, while the effect on weed species richness was less important. Our results also show that the effect of crop competition on the weed assemblage was much stronger than the effect of N fertilizer and weed control. The decrease in weed abundance and biomass mainly resulted from a strong effect of the crop on the dominant species, while the abundance of intermediate species tended to be much less affected, a result consistent with studies in grasslands where the removal of the dominant species provides a competitive release for subordinate ones. Our results further give experimental support for crop competition as a way to reduce costly agricultural inputs for weed control. Conducting experiments with farmers in their field is a valuable approach to generate knowledge for the future delivery of sustainable management
Colonisation des paysages agricoles par les espèces des bordures adjacentes : apports de l’approche fonctionnelle
No full textSPE GEAPSINational audienceUne crainte avancée par les agriculteurs repose sur l’hypothèse qu’une gestion plus raisonnée des bordures adjacentes aux champs cultivés pourrait, par relâchement de la pression de fauche, favoriser l’entrée de nouvelles espèces, bisannuelles ou pérennes, dans les parcelles agricoles. Afin de répondre à cette interrogation, notre objectif a été de proposer un cadre conceptuel théorique associant plusieurs champs disciplinaires de l’écologie. En comparaison des études précédemment réalisées, notre apport réside en la prise en compte des traits fonctionnels favorisant la dispersion à courte et longue distance, ainsi que des traits expliquant le maintien de populations viables de ces espèces, colonisatrices potentielles des parcelles agricoles. Pour se faire, (i) le modèle de filtres successifs proposé par Belyea & Lancaster (1999), associé à une approche fonctionnelle, nous fournit tout d’abord un cadre d’analyse des mécanismes d’assemblage de la flore. Il repose sur l’hypothèse que les communautés observées résultent de l’action de différents filtres biotiques et abiotiques triant la flore régionale de manière relativement distincte entre compartiments d’un champ. Si les conditions locales façonnent l’assemblage des espèces en communautés, (ii) la seule observation d’une espèce dans un compartiment n’assure cependant pas son maintien sous forme de populations viables. En effet, sa présence peut être alimentée par des phénomènes de dispersion favorisés par la proximité spatiale d’un habitat potentiellement plus favorable. Seule une étude de sa performance dans les conditions environnementales locales, couplée à l’étude de sa dynamique de dispersion entre compartiments, est à même de différencier les espèces inaptes au maintien de populations viables en champ cultivé, d’autres espèces, colonisatrices potentielles. Une fois établie en parcelle agricole, (iii) il est important de qualifier le risque de dispersion de chaque nouvelle espèce à l’échelle paysagère afin d’identifier les espèces pouvant devenir problématiques dans les prochaines années pour les exploitants de la région agricole. Ce diagnostic nécessite la prise en compte des différents modes de dispersion connus pour cette espèce, qu’ils soient primaires et/ou secondaires, via des échanges inter-bordures et/ou inter-parcelles. S’appuyant sur ce schéma conceptuel, nous proposons une liste de caractéristiques fonctionnelles permettant d’effectuer un premier tri des espèces observées dans la bordure, entre flore stricte des bordures et adventices en devenir, dans l’objectif d’identifier les principales stratégies tout en tenant compte des systèmes de culture. Cette approche conceptuelle constitue un premier pas afin d’adapter les pratiques de gestion des bordures tout en tenant compte des interrogations des acteurs. Références : Beleya LR, Lancaster J (1999) Assembly rules within a contingent ecology. O ikos 86: 402–416
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