168 research outputs found
Insights from in\ua0vivo micro-CT analysis: testing the hydraulic vulnerability segmentation in Acer pseudoplatanus and Fagus sylvatica seedlings
The seedling stage is the most susceptible one during a tree\u2032s life. Water relations may be crucial for seedlings due to their small roots, limited water buffers and the effects of drought on water transport. Despite obvious relevance, studies on seedling xylem hydraulics are scarce as respective methodical approaches are limited.
Micro\u2010CT scans of intact Acer pseudoplatanus and Fagus sylvatica seedlings dehydrated to different water potentials (\u3a8) allowed the simultaneous observation of gas\u2010filled versus water\u2010filled conduits and the calculation of percentage loss of conductivity (PLC) in stems, roots and leaves (petioles or main veins). Additionally, anatomical analyses were performed and stem PLC measured with hydraulic techniques.
In A. pseudoplatanus, petioles showed a higher \u3a8 at 50% PLC (\u3a850 121.13MPa) than stems ( 122.51 MPa) and roots ( 121.78 MPa). The main leaf veins of F. sylvatica had similar \u3a850 values ( 122.26 MPa) to stems ( 122.74 MPa) and roots ( 122.75 MPa). In both species, no difference between root and stems was observed. Hydraulic measurements on stems closely matched the micro\u2010CT based PLC calculations.
Micro\u2010CT analyses indicated a species\u2010specific hydraulic architecture. Vulnerability segmentation, enabling a disconnection of the hydraulic pathway upon drought, was observed in A. pseudoplatanus but not in the especially shade\u2010tolerant F. sylvatica. Hydraulic patterns could partly be related to xylem anatomical traits
Transcriptome sequencing and microarray development for the Manila clam, Ruditapes philippinarum: genomic tools for environmental monitoring
Abstract Background The Manila clam, Ruditapes philippinarum, is one of the major aquaculture species in the world and a potential sentinel organism for monitoring the status of marine ecosystems. However, genomic resources for R. philippinarum are still extremely limited. Global analysis of gene expression profiles is increasingly used to evaluate the biological effects of various environmental stressors on aquatic animals under either artificial conditions or in the wild. Here, we report on the development of a transcriptomic platform for global gene expression profiling in the Manila clam. Results A normalized cDNA library representing a mixture of adult tissues was sequenced using a ultra high-throughput sequencing technology (Roche 454). A database consisting of 32,606 unique transcripts was constructed, 9,747 (30%) of which could be annotated by similarity. An oligo-DNA microarray platform was designed and applied to profile gene expression of digestive gland and gills. Functional annotation of differentially expressed genes between different tissues was performed by enrichment analysis. Expression of Natural Antisense Transcripts (NAT) analysis was also performed and bi-directional transcription appears a common phenomenon in the R. philippinarum transcriptome. A preliminary study on clam samples collected in a highly polluted area of the Venice Lagoon demonstrated the applicability of genomic tools to environmental monitoring. Conclusions The transcriptomic platform developed for the Manila clam confirmed the high level of reproducibility of current microarray technology. Next-generation sequencing provided a good representation of the clam transcriptome. Despite the known limitations in transcript annotation and sequence coverage for non model species, sufficient information was obtained to identify a large set of genes potentially involved in cellular response to environmental stress.This work was partially supported by a grant from European Union-funded Network of Excellence "Marine Genomics Europe". CS wishes to acknowledge additional funding from the Ministry of Education and Science (Spain) through grant AGL2007-60049. MM had a PhD scholarship from the University of Florence, Italy. RL was recipient of PhD fellowship SFRH/BD/30112/2006, from the Portuguese Science and Technology Foundation (FCT) and LC and RL acknowledge a grant from FCT project ISOPERK (PTDC/CVT/72083/2006).Peer Reviewe
HLA-Driven Convergence of HIV-1 Viral Subtypes B and F Toward the Adaptation to Immune Responses in Human Populations
BACKGROUND: Cytotoxic T-Lymphocyte (CTL) response drives the evolution of HIV-1 at a host-level by selecting HLA-restricted escape mutations. Dissecting the dynamics of these escape mutations at a population-level would help to understand how HLA-mediated selection drives the evolution of HIV-1. METHODOLOGY/PRINCIPAL FINDINGS: We undertook a study of the dynamics of HIV-1 CTL-escape mutations by analyzing through statistical approaches and phylogenetic methods the viral gene gag sequenced in plasma samples collected between the years 1987 and 2006 from 302 drug-naive HIV-positive patients. By applying logistic regression models and after performing correction for multiple test, we identified 22 potential CTL-escape mutations (p-value<0.05; q-value<0.2); 10 of these associations were confirmed in samples biologically independent by a Bayesian Markov Chain Monte-Carlo method. Analyzing their prevalence back in time we found that escape mutations that are the consensus residue in samples collected after 2003 have actually significantly increased in time in one of either B or F subtype until becoming the most frequent residue, while dominating the other viral subtype. Their estimated prevalence in the viral subtype they did not dominate was lower than 30% for the majority of samples collected at the end of the 80's. In addition, when screening the entire viral region, we found that the 75% of positions significantly changing in time (p<0.05) were located within known CTL epitopes. CONCLUSIONS: Across HIV Gag protein, the rise of polymorphisms from independent origin during the last twenty years of epidemic in our setting was related to an association with an HLA allele. The fact that these mutations accumulated in one of either B or F subtypes have also dominated the other subtype shows how this selection might be causing a convergence of viral subtypes to variants which are more likely to evade the immune response of the population where they circulate
Increased indoleamine-2,3-dioxygenase activity is associated with poor clinical outcome in adults hospitalized with influenza in the INSIGHT FLU003Plus study
BACKGROUND:
Indoleamine-2,3-dioxygenase (IDO) mediated tryptophan (TRP) depletion has antimicrobial and immuno-regulatory effects. Increased kynurenine (KYN)-to-TRP (KT) ratios, reflecting increased IDO activity, have been associated with poorer outcomes from several infections.
METHODS:
We performed a case-control (1:2; age and sex matched) analysis of adults hospitalized with influenza A(H1N1)pdm09 with protocol-defined disease progression (died/transferred to ICU/mechanical ventilation) after enrollment (cases) or survived without progression (controls) over 60 days of follow-up. Conditional logistic regression was used to analyze the relationship between baseline KT ratio and other metabolites and disease progression.
RESULTS:
We included 32 cases and 64 controls with a median age of 52 years; 41% were female, and the median durations of influenza symptoms prior to hospitalization were 8 and 6 days for cases and controls, respectively (P = .04). Median baseline KT ratios were 2-fold higher in cases (0.24 mM/M; IQR, 0.13-0.40) than controls (0.12; IQR, 0.09-0.17; P ≤ .001). When divided into tertiles, 59% of cases vs 20% of controls had KT ratios in the highest tertile (0.21-0.84 mM/M). When adjusted for symptom duration, the odds ratio for disease progression for those in the highest vs lowest tertiles of KT ratio was 9.94 (95% CI, 2.25-43.90).
CONCLUSIONS:
High KT ratio was associated with poor outcome in adults hospitalized with influenza A(H1N1)pdm09. The clinical utility of this biomarker in this setting merits further exploration.
CLINICALTRIALSGOV IDENTIFIER:
NCT01056185
Infection-related and -unrelated malignancies, HIV and the aging population
Funding Information: Conflicts of interest: JR reports personal fees from Abbvie, Bionor, BMS, Boehringer, Gilead, Merck, Janssen, Tobira, Tibotec and ViiV, outside the submitted work. OK has received honoraria, consultancy and/or lecture fees from Abbott, Gilead, GSK, Janssen, Merck, Tibotec and Viiv outside the submitted work. All other authors state no commercial or other associations that may pose a conflict of interest. Funding: Primary support for EuroSIDA is provided by the European Commission BIOMED 1 (CT94-1637), BIOMED 2 (CT97-2713), 5th Framework (QLK2-2000-00773), 6th Framework (LSHP-CT-2006-018632) and 7th Framework (FP7/2007?2013; EuroCoord n? 260694) programmes. Current support also includes unrestricted grants from Janssen R&D, Merck and Co. Inc., Pfizer Inc. and GlaxoSmithKline LLC. The participation of centres in Switzerland was supported by The Swiss National Science Foundation (Grant 108787). The authors have no financial disclosures to make. Author contributions: LS developed the project, analysed the data, and was responsible for writing the manuscript. ?HB and OK contributed to the study design and analysis, interpretation of the data and writing of the manuscript. JL proposed the project and contributed to the study design, ideas for analysis, interpretation of the data and writing of the manuscript. BL, PD, AC, JR, BK, JT and IK contributed to national coordination, study design and writing of the manuscript. AM supervised the project and contributed to the study design and analysis, interpretation of the data and writing of the manuscript. Publisher Copyright: © 2016 British HIV AssociationObjectives: HIV-positive people have increased risk of infection-related malignancies (IRMs) and infection-unrelated malignancies (IURMs). The aim of the study was to determine the impact of aging on future IRM and IURM incidence. Methods: People enrolled in EuroSIDA and followed from the latest of the first visit or 1 January 2001 until the last visit or death were included in the study. Poisson regression was used to investigate the impact of aging on the incidence of IRMs and IURMs, adjusting for demographic, clinical and laboratory confounders. Linear exponential smoothing models forecasted future incidence. Results: A total of 15 648 people contributed 95 033 person-years of follow-up, of whom 610 developed 643 malignancies [IRMs: 388 (60%); IURMs: 255 (40%)]. After adjustment, a higher IRM incidence was associated with a lower CD4 count [adjusted incidence rate ratio (aIRR) CD4 count < 200 cells/μL: 3.77; 95% confidence interval (CI) 2.59, 5.51; compared with ≥ 500 cells/μL], independent of age, while a CD4 count < 200 cells/μL was associated with IURMs in people aged < 50 years only (aIRR: 2.51; 95% CI 1.40–4.54). Smoking was associated with IURMs (aIRR: 1.75; 95% CI 1.23, 2.49) compared with never smokers in people aged ≥ 50 years only, and not with IRMs. The incidences of both IURMs and IRMs increased with older age. It was projected that the incidence of IRMs would decrease by 29% over a 5-year period from 3.1 (95% CI 1.5–5.9) per 1000 person-years in 2011, whereas the IURM incidence would increase by 44% from 4.1 (95% CI 2.2–7.2) per 1000 person-years over the same period. Conclusions: Demographic and HIV-related risk factors for IURMs (aging and smoking) and IRMs (immunodeficiency and ongoing viral replication) differ markedly and the contribution from IURMs relative to IRMs will continue to increase as a result of aging of the HIV-infected population, high smoking and lung cancer prevalence and a low prevalence of untreated HIV infection. These findings suggest the need for targeted preventive measures and evaluation of the cost−benefit of screening for IURMs in HIV-infected populations.publishersversionPeer reviewe
Hepatitis delta infection among persons living with HIV in Europe
BACKGROUND AND AIMS: A high prevalence of hepatitis delta virus (HDV) infection, the most severe form of viral hepatitis, has been reported among persons living with HIV (PLWH) in Europe. We analysed data from a large HIV cohort collaboration to characterize HDV epidemiological trends across Europe, as well as its impact on clinical outcomes. METHODS: All PLWH with a positive hepatitis B surface antigen (HBsAg) in the Swiss HIV Cohort Study and EuroSIDA between 1988 and 2019 were tested for anti-HDV antibodies and, if positive, for HDV RNA. Demographic and clinical characteristics at initiation of antiretroviral therapy were compared between HDV-positive and HDV-negative individuals using descriptive statistics. The associations between HDV infection and overall mortality, liver-related mortality as well as hepatocellular carcinoma (HCC) were assessed using cumulative incidence plots and cause-specific multivariable Cox regression. RESULTS: Of 2793 HBsAg-positive participants, 1556 (56%) had stored serum available and were included. The prevalence of HDV coinfection was 15.2% (237/1556, 95% confidence interval [CI]: 13.5%–17.1%) and 66% (132/200) of HDV-positive individuals had active HDV replication. Among persons who inject drugs (PWID), the prevalence of HDV coinfection was 50.5% (182/360, 95% CI: 45.3%–55.7%), with similar estimates across Europe, compared to 4.7% (52/1109, 95% CI: 3.5%–5.9%) among other participants. During a median follow-up of 10.8 years (interquartile range 5.6–17.8), 82 (34.6%) HDV-positive and 265 (20.1%) HDV-negative individuals died. 41.5% (34/82) of deaths were liver-related in HDV-positive individuals compared to 17.7% (47/265) in HDV-negative individuals. HDV infection was associated with overall mortality (adjusted hazard ratio 1.6; 95% CI 1.2–2.1), liver-related death (2.9, 1.6–5.0) and HCC (6.3, 2.5–16.0). CONCLUSION: We found a very high prevalence of hepatitis delta among PWID across Europe. Among PLWH who do not inject drugs, the prevalence was similar to that reported from populations without HIV. HDV coinfection was associated with liver-related mortality and HCC incidence
Ellagic Acid Derivatives from Rubus ulmifolius Inhibit Staphylococcus aureus Biofilm Formation and Improve Response to Antibiotics
Biofilms contribute to the pathogenesis of many forms of Staphylococcus aureus infection. Treatment of these infections is complicated by intrinsic resistance to conventional antibiotics, thus creating an urgent need for strategies that can be used for the prevention and treatment of biofilm-associated infections.This study demonstrates that a botanical natural product composition (220D-F2) rich in ellagic acid and its derivatives can limit S. aureus biofilm formation to a degree that can be correlated with increased antibiotic susceptibility. The source of this composition is Rubus ulmifolius Schott. (Rosaceae), a plant used in complementary and alternative medicine in southern Italy for the treatment of skin and soft tissue infections. All S. aureus clonal lineages tested exhibited a reduced capacity to form a biofilm at 220D-F2 concentrations ranging from 50-200 µg/mL, which were well below the concentrations required to limit bacterial growth (530-1040 µg/mL). This limitation was therapeutically relevant in that inclusion of 220D-F2 resulted in enhanced susceptibility to the functionally-distinct antibiotics daptomycin, clindamycin and oxacillin. Testing with kidney and liver cell lines also demonstrated a lack of host cell cytotoxicity at concentrations of 220D-F2 required to achieve these effects.These results demonstrate that extract 220D-F2 from the root of Rubus ulmifolius can be used to inhibit S. aureus biofilm formation to a degree that can be correlated with increased antibiotic susceptibility without toxic effects on normal mammalian cells. Hence, 220D-F2 is a strong candidate for development as a botanical drug for use in the prevention and treatment of S. aureus biofilm-associated infections
Incidence of cancer and overall risk of mortality in individuals treated with raltegravir-based and non-raltegravir-based combination antiretroviral therapy regimens
Objectives: There are currently few data on the long-term risk of cancer and death in individuals taking raltegravir (RAL). The aim of this analysis was to evaluate whether there is evidence for an association. Methods: The EuroSIDA cohort was divided into three groups: those starting RAL-based combination antiretroviral therapy (cART) on or after 21 December 2007 (RAL); a historical cohort (HIST) of individuals adding a new antiretroviral (ARV) drug (not RAL) to their cART between 1 January 2005 and 20 December 2007, and a concurrent cohort (CONC) of individuals adding a new ARV drug (not RAL) to their cART on or after 21 December 2007. Baseline characteristics were compared using logistic regression. The incidences of newly diagnosed malignancies and death were compared using Poisson regression. Results: The RAL cohort included 1470 individuals [with 4058 person-years of follow-up (PYFU)] compared with 3787 (4472 PYFU) and 4467 (10 691 PYFU) in the HIST and CONC cohorts, respectively. The prevalence of non-AIDS-related malignancies prior to baseline tended to be higher in the RAL cohort vs. the HIST cohort [adjusted odds ratio (aOR) 1.31; 95% confidence interval (CI) 0.95–1.80] and vs. the CONC cohort (aOR 1.89; 95% CI 1.37–2.61). In intention-to-treat (ITT) analysis (events: RAL, 50; HIST, 45; CONC, 127), the incidence of all new malignancies was 1.11 (95% CI 0.84–1.46) per 100 PYFU in the RAL cohort vs. 1.20 (95% CI 0.90–1.61) and 0.83 (95% CI 0.70–0.99) in the HIST and CONC cohorts, respectively. After adjustment, there was no evidence for a difference in the risk of malignancies [adjusted rate ratio (RR) 0.73; 95% CI 0.47–1.14 for RALvs. HIST; RR 0.95; 95% CI 0.65–1.39 for RALvs. CONC] or mortality (adjusted RR 0.87; 95% CI 0.53–1.43 for RALvs. HIST; RR 1.14; 95% CI 0.76–1.72 for RALvs. CONC). Conclusions: We found no evidence for an oncogenic risk or poorer survival associated with using RAL compared with control groups.Peer reviewe
Establishing a hepatitis C continuum of care among HIV/hepatitis C virus-coinfected individuals in EuroSIDA
Objectives The aim of the study was to establish a methodology for evaluating the hepatitis C continuum of care in HIV/hepatitis C virus (HCV)-coinfected individuals and to characterize the continuum in Europe on 1 January 2015, prior to widespread access to direct-acting antiviral (DAA) therapy. Methods Stages included in the continuum were as follows: anti-HCV antibody positive, HCV RNA tested, currently HCV RNA positive, ever HCV RNA positive, ever received HCV treatment, completed HCV treatment, follow-up HCV RNA test, and cure. Sustained virological response (SVR) could only be assessed for those with a follow-up HCV RNA test and was defined as a negative HCV RNA result measured > 12 or 24 weeks after stopping treatment. Results Numbers and percentages for the stages of the HCV continuum of care were as follows: anti-HCV positive (n = 5173), HCV RNA tested (4207 of 5173; 81.3%), currently HCV RNA positive (3179 of 5173; 61.5%), ever HCV RNA positive (n = 3876), initiated HCV treatment (1693 of 3876; 43.7%), completed HCV treatment (1598 of 3876; 41.2%), follow-up HCV RNA test to allow SVR assessment (1195 of 3876; 30.8%), and cure (629 of 3876; 16.2%). The proportion that achieved SVR was 52.6% (629 of 1195). There were significant differences between regions at each stage of the continuum (P <0.0001). Conclusions In the proposed HCV continuum of care for HIV/HCV-coinfected individuals, we found major gaps at all stages, with almost 20% of anti-HCV-positive individuals having no documented HCV RNA test and a low proportion achieving SVR, in the pre-DAA era.Peer reviewe
Contribution of Genetic Background, Traditional Risk Factors, and HIV-Related Factors to Coronary Artery Disease Events in HIV-Positive Persons
We show in human immunodeficiency virus-positive persons that the coronary artery disease effect of an unfavorable genetic background is comparable to previous studies in the general population, and comparable in size to traditional risk factors and antiretroviral regimens known to increase cardiovascular ris
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