48 research outputs found

    Sofosbuvir-based therapies in genotype 2 hepatitis C virus cirrhosis: A real-life experience with focus on ribavirin dose

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    This study aimed to investigate the efficacy and safety of sofosbuvir-based therapies for the treatment of cirrhosis from hepatitis C virus (HCV) genotype 2 infection. Data of all consecutive HCV genotype 2 cirrhotic patients who started sofosbuvir-based treatments between January 2015 and March 2017 in eight Italian tertiary hospitals were collected retrospectively. Overall, 273 patients (Child A: 94.5%) were enrolled. In the 194 subjects treated with sofosbuvir/ribavirin, median initial ribavirin dosage was 13.9 mg/kg/day, and therapy duration was 16 weeks. Sustained virological response (SVR) rates were 93.8% in intention-to-treat (ITT) and 95.3% in per-protocol (PP) analyses for the 129 treatment-naĂŻve patients, and 96.9% (ITT) and 98.4% (PP) for the 65 treatment-experienced subjects. Adverse events were reported in 142 patients (73.2%), but only 1.5% discontinued treatment. Eighty-eight subjects with treatment-induced anemia (mild: 34.5%, moderate: 7.7%, severe: 3.1%) had to reduce ribavirin dosage, but SVR rates were comparable to the weight-based dose group, both in ITT (95.4% and 94.3%) and PP (97.7% and 95.2%) analyses, respectively. Moreover, ITT and PP SVR rates were similar between shorter (<20 weeks) (94.1% and 96.0%, respectively) and prolonged (≄20 weeks) regimens (95.7% and 96.7%, respectively). SVR rates in the 79 subjects treated with sofosbuvir/daclatasvir (without ribavirin) were similar (ITT: 96.2%; PP: 97.4%, respectively), without de novo/worsening anemia. In conclusion, in a real-life study centered on genotype 2 patients with well-compensated cirrhosis, sofosbuvir-based regimens were associated with good SVR and tolerability rates, regardless of previous antiviral treatments, without a significant impact of on treatment ribavirin dose reductions

    Detrimental Impact of Interferon-Based Regimens for Chronic Hepatitis C on Vitamin D/Parathyroid Hormone Homeostasis

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    Background: Both the anti-infective and anti-inflammatory properties of vitamin D, an essential hormone of calcium homeostasis, have ample support in the literature. The high rates of vitamin D deficiency among patients with chronic hepatitis C are also well known. That supplementation with vitamin D may boost sustained viral response rates in vitamin D deficient, hepatitis C virus (HCV) infected patients undergoing Interferon-alpha (IFN) treatment, on the other hand, is controversial. Surprisingly, studies considering in this latter setting what are the effects of IFN treatment (with or without vitamin D supplementation) on the other major regulator of mineral metabolism, i.e. the Parathyroid hormone (PTH), are lacking. Aim: Evaluate the impact of interferon-based treatment against HCV (±cholecalciferol supplementation) on vitamin D and PTH homeostasis. Methods: A series of 40 consecutive patients received pegylated IFN plus ribavirin to treat chronic hepatitis C. At the discretion of their physician, some of them (N. = 27) received vitamin D supplementation while others did not (N. = 13). All had measured plasma 25-hydroxycholecalciferol and PTH concentrations at baseline, at completion of the 4th (TW4) and 12th treatment week (TW12) and at 24 weeks after the end of therapy (SVR24). Results: Plasma PTH concentration increased significantly from baseline during treatment, raising to 44.8 [30.7-57.2] pg/mL at TW4 (p=0.01), 47.0 [37.1-63.2] pg/mL at TW12 (p=0.006) to return to baseline levels in the follow-up (34.5 [27.6-43.0]; p=0.16). The proportion of patients who satisfied criteria for hyperparathyroidism was higher at TW12 (N=10, 25%) than at TW4 (N=6, 15%). There was no statistical correlation between vitamin D and PTH blood levels (ρ=-0.07; p=0.65). Conclusion: An increase in plasma PTH occurs systematically during IFN treatment of HCV patients and cannot be prevented by vitamin D supplementation

    Population- and individual-specific regulatory variation in Sardinia

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    Genetic studies of complex traits have mainly identified associations with noncoding variants. To further determine the contribution of regulatory variation, we combined whole-genome and transcriptome data for 624 individuals from Sardinia to identify common and rare variants that influence gene expression and splicing. We identified 21,183 expression quantitative trait loci (eQTLs) and 6,768 splicing quantitative trait loci (sQTLs), including 619 new QTLs. We identified high-frequency QTLs and found evidence of selection near genes involved in malarial resistance and increased multiple sclerosis risk, reflecting the epidemiological history of Sardinia. Using family relationships, we identified 809 segregating expression outliers (median z score of 2.97), averaging 13.3 genes per individual. Outlier genes were enriched for proximal rare variants, providing a new approach to study large-effect regulatory variants and their relevance to traits. Our results provide insight into the effects of regulatory variants and their relationship to population history and individual genetic risk.M.P. is supported by the European Union’s Horizon 2020 Research and Innovation Programme under grant agreement 633964 (ImmunoAgeing). Z.Z. is supported by the National Science Foundation (NSF) GRFP (DGE- 114747) and by the Stanford Center for Computational, Evolutionary, and Human Genomics (CEHG). Z.Z., J.R.D., and G.T.H. also acknowledge support from the Stanford Genome Training Program (SGTP; NIH/NHGRI T32HG000044). J.R.D. is supported by the Stanford Graduate Fellowship. K.R.K. is supported by Department of Defense, Air Force Office of Scientific Research, National Defense Science and Engineering Graduate (NDSEQ) Fellowship 32 CFR 168a. S.J.S. is supported by the NIHR Cambridge Biomedical Research Centre. The SardiNIA project is supported in part by the intramural program of the National Institute on Aging through contract HHSN271201100005C to the Consiglio Nazionale delle Ricerche of Italy. The RNA sequencing was supported by the PB05 InterOmics MIUR Flagship grant; by the FaReBio2011 “Farmaci e Reti Biotecnologiche di Qualità” grant; and by Sardinian Autonomous Region (L.R. no. 7/2009) grant cRP3-154 to F. Cucca, who is also supported by the Italian Foundation for Multiple Sclerosis (FISM 2015/R/09) and by the Fondazione di Sardegna (ex Fondazione Banco di Sardegna, Prot. U1301.2015/AI.1157.BE Prat. 2015-1651). S.B.M. is supported by the US National Institutes of Health through R01HG008150, R01MH101814, U01HG007436, and U01HG009080. All of the authors would like to thank the CRS4 and the SCGPM for the computational infrastructure supporting this project

    Plasmodium falciparum ferredoxin-NADP+ reductase : unique structural and functional properties of a plant-type enzyme

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    INTRODUCTION: Plant-type ferredoxin-NADP+ reductases (FNRs) are a widespread group of flavin-dependent enzymes that catalyze the exchange of reducing equivalents between NADP(H) and ferredoxin (Fd) (1). FNRs have been found in plant plastids, cyanobacteria and some eubacteria (1), where they form electron transport chains involved in biosynthetic processes as diverse as photosynthesis, nitrogen assimilation, and response against reactive oxygen species. FNRs have been recently identified in the apicoplast of apicomplexan parasites (2, 3), which includes the causative agents of malaria and toxoplasmosis. Plasmodium falciparum FNR (PfFNR) and Fd (PfFd) have been cloned and functionally characterized (4-6). The PfFNR/PfFd couple has been shown to support in vitro the activity of LytB (6), the last enzyme of the biosynthetic pathway for isoprenoid precursors, which is the site of action of known antiplasmodial compounds. On this basis, PfFNR has been proposed as a possible new target for antimalarial drugs (3). RESULTS: The structure of PfFNR has been determined by X-ray crystallography. Compared to other plastidic-type FNRs, PfFNR displays a significantly lower catalytic efficiency and lower selectivity against NADH. These functional features are probably the consequence of the lack of protein positively-charged groups stabilizing the 2\u2019-phosphate of bound substrate. PfFNR interacts with the adenine moiety of the bound NADP(H) through a His residues not conserved in other FNRs. The role of this residue in catalysis has been investigated by site-directed mutagenesis. NADP(H)-binding to PfFNR occurs through an induced-fit mechanism unprecedented in other enzyme of this protein family. The conformational changes induced by binding to the enzyme of 2\u2019-P-AMP, a NADP analogue, include the partial disruption of an \u3b1-helix localized in the NADP-binding domain. Furthermore, PfFNR was shown to undergo NADP+-triggered homodimerization in vitro, resulting in the formation of an intermolecular disulfide bridge and leading to enzyme inactivation. This process, which can be fully reversed by cleaving the disulfide by reductants like DTT or lipoate, could represent a physiologic mechanism regulating the enzyme activity. Structure-based design of PfFNR inhibitors is in progress and has already yielded some active compounds. 1. Ceccarelli E.A. et al. (2004) Biochim. Biophys. Acta 1698, 155-165 2. Pandini V. et al. (2002) J. Biol. Chem. 277, 48463-48471 3. Seeber F. et al. (2005) Curr. Farm. Des. 11, 3159-7312 4. Milani M. et al. (2007) J. Mol. Biol. 367, 501-513 5. Kimata\u2013Ariga Y. et al. (2007) J. Biochem. 142, 715-720 6. R\uf6hrich R.C. et al. (2005) FEBS Lett. 579, 6433\u2013643

    Late Oligocene Warming Event (LOWE) possibly preserved on top of a reef drowning sequence in NW Italy: insights from an integrated stratigraphic approach.

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    none6noopenBriguglio A., Vannucci M.G., Bruzzone C., Crobu S., Lutaj E., Piazza M.Briguglio, A.; Vannucci, M. G.; Bruzzone, C.; Crobu, S.; Lutaj, E.; Piazza, M

    Plasmodium falciparum ferredoxin-NADP+ reductase : a plant-type enzyme as a promising new target for novel antimalarial drugs

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    INTRODUCTION: Plant-type ferredoxin-NADP+ reductases (FNRs) are a widespread group of flavin-dependent enzymes that catalyze the exchange of reducing equivalents between NADP(H) and ferredoxin (Fd) (1). FNRs have been found in plant plastids, cyanobacteria and some eubacteria (1), where they form electron transport chains involved in biosynthetic processes as diverse as photosynthesis, nitrogen assimilation, and response against reactive oxygen species. FNRs have been recently identified in the apicoplast of apicomplexan parasites (2, 3), which includes the causative agents of malaria and toxoplasmosis. Plasmodium falciparum FNR (PfFNR) and Fd (PfFd) have been cloned and functionally characterized (4-6). The PfFNR/PfFd couple has been shown to support in vitro the activity of LytB (6), the last enzyme of the biosynthetic pathway for isoprenoid precursors, which is the site of action of known antiplasmodial compounds. On this basis, PfFNR has been proposed as a possible new target for antimalarial drugs (3). RESULTS: The structure of PfFNR has been determined by X-ray crystallography. Compared to other plastidic-type FNRs, PfFNR displays a significantly lower catalytic efficiency and lower selectivity against NADH. These functional features are probably the consequence of the lack of protein positively-charged groups stabilizing the 2\u2019-phosphate of bound substrate. PfFNR interacts with the adenine moiety of the bound NADP(H) through a His residues not conserved in other FNRs. The role of this residue in catalysis has been investigated by site-directed mutagenesis. NADP(H)-binding to PfFNR occurs through an induced-fit mechanism unprecedented in other enzyme of this protein family. The conformational changes induced by binding to the enzyme of 2\u2019-P-AMP, a NADP analogue, include the partial disruption of an \u3b1-helix localized in the NADP-binding domain. Furthermore, PfFNR was shown to undergo NADP+-triggered homodimerization in vitro, resulting in the formation of an intermolecular disulfide bridge and leading to enzyme inactivation. This process, which can be fully reversed by cleaving the disulfide by reductants like DTT or lipoate, could represent a physiologic mechanism regulating the enzyme activity. Structure-based design of PfFNR inhibitors is in progress and has already yielded some active compounds. 1. Ceccarelli E.A. et al. (2004) Biochim. Biophys. Acta 1698, 155-165 2. Pandini V. et al. (2002) J. Biol. Chem. 277, 48463-48471 3. Seeber F. et al. (2005) Curr. Farm. Des. 11, 3159-7312 4. Milani M. et al. (2007) J. Mol. Biol. 367, 501-513 5. Kimata\u2013Ariga Y. et al. (2007) J. Biochem. 142, 715-720 6. R\uf6hrich R.C. et al. (2005) FEBS Lett. 579, 6433\u2013643

    Plasmodium falciparum ferredoxin-NADP+ reductase: unique structural and functional properties of a plant-type enzyme

    No full text
    Plant-type ferredoxin-NADP+ reductases (FNRs) represent a widespread group of flavin-dependent dehydrogenases/electron transferases that catalyze the exchange of reducing equivalents between NADP(H) and ferredoxin (Fd) or flavodoxin [1]. FNRs have been found in plant plastids, cyanobacteria and some eubacteria [1]. FNRs structurally similar to those present in non-photosynthetic plastids, have been identified in the apicoplast of apicomplexan parasites [2,3], which includes the causative agents of malaria and toxoplasmosis. Plasmodium falciparum FNR (PfFNR) and Fd (PfFd) have been cloned and characterized. The crystal structure of both proteins has been determined [4,5]. Compared to other plastidic-type FNRs, PfFNR displays a significantly lower catalytic efficiency and lower selectivity against NADH [4]. These functional features are probably the consequence of the lack of protein positively-charged groups stabilizing the 2\u2019-phosphate of bound substrate. NADP(H)-binding to PfFNR occurs through an unprecedented induced-fit mechanism that involves the partial unwinding of a helix. Furthermore, PfFNR undergoes a redox-dependent homodimerization process leading to enzyme inactivation, which could represent a regulatory mechanism. The PfFNR/PfFd couple has been shown to support in vitro the activity of LytB [6], the last enzyme of the biosynthetic pathway of isoprenoid precursors, site of action of known antiplasmodial compounds. On this basis, PfFNR has been proposed as a possible new target for antimalarial drugs [3]. Structure-based design of PfFNR inhibitors is in progress and has already yielded some active compounds. [1] Ceccarelli, E.A., Arakaki, A.K. Cortez, N., and Carrillo, N. (2004) Biochim. Biophys. Acta 1698, 155-165. [2] Pandini, V., Caprini, G., Thomsen, N., Aliverti, A., Seeber, F., and Zanetti, G. (2002) J. Biol. Chem. 277, 48463-48471. [3] Seeber, F., Aliverti, A., and Zanetti, G. (2005) Curr. Farm. Des. 11, 3159-7312. [4] Milani, M., Balconi, E., Aliverti, A., Mastrangelo, E., Seeber, F., Bolognesi, M., and Zanetti, G. (2007) J. Mol. Biol. 367, 501-513. [5] Kimata\u2013Ariga, Y., Saitoh, T., Ikegami, T., Horii, T., and Hase, T. (2007) J. Biochem. 142, 715-720. [6] R\uf6hrich, R.C., Englert, N., Troschke, K., Reichenberg, A., Hintz, M., Seeber, F., Balconi, E., Aliverti, A., Zanetti, G., K\uf6hler, U., Pfeiffer, M., Beck, E., Jomaa, H., and Wiesner, J. (2005) FEBS Lett. 579, 6433\u20136438
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