169,852 research outputs found
Conventional protein kinase C inhibition prevents alpha interferon-mediated hepatitis C virus replication clearance
No full textAlpha interferon (IFNa), alone in combination vith ribavirin, represents the only available treatment for HCV infections, with a moderate percentage of virus eradication (30-40 % ot the patoents). The mechanisms by which IFNa interferes with HCV replication have not been elucidated, nor are the reasons for limited effectiveness of INFa therapy known. Using a cell-based HCV replication system and specific kinase inhibitors we examined the role played by various signalling pathways in the IFNa-mediated HCV clearance. We have found thet conventional PKC activity is important for the effectiveness of IFNa treatment. In cells treated with a cPKC specific inhibitor, IFNa failed to induce an effective HCV RNA degradation. The lack of cPKC activity leads to a broad reduction of IFN-stimulated gene expression due to a significant impairment of STAT1 and STAT3 tyrosine phosphorylation. Thus, modulation of cPKC function, by either host or viral factors, could influence the positive outcome of IFN-mediated antiviral therap
Evolution and Reversibility of Host/Guest Interactions with Temperature Changes in a Methyl Red@Palygorskite Polyfunctional Hybrid Nanocomposite
No full textPalygorskite is a microporous clay mineral with several important applications, including use as dye nano-scaffold, due to its ability to incorporate apt guest molecules and form exceptionally stable composites. Such a property covers widespread fields of interest, from pottery pigments to light harvesting. In all these applications, the stability of these composites at progressively increasing temperatures is an important parameter to determine their condition of usage. This work investigates the nature and strength of the stabilizing host/guest interactions at the basis of the exceptional stability of the methyl red@palygorskite composite system, which undergo a dynamic but reversible evolution depending on the level of heating. A multi-technique analytical protocol involving synchrotron X-ray powder diffraction (S-XRPD) and thermogravimetric analysis (TGA) coupled with infrared spectroscopy (FT-IR) and gas chromatography (GC-MS) was followed, which allowed to sharply identify the species evolved during heating. Moderate temperatures (140°-300°C) cause stabilization of H-bonds between the structural H2O and the carboxyl group of the dye, whereas higher ones (> 300°C) trigger formation of direct COOH/octahedral Mg bonds favoured by dehydration. Cooling below 300°C implies gradual reversibility of the observed trend due to rehydration from environmental moisture; additional heating (> 400°C), conversely, causes methyl red decomposition, fragmentation and further expulsion from the host tunnels ( 500°C). The encapsulated dye in zwitterionic, trans and/or protonated form affects the hosting system properties, preventing structural folding and strongly modifying the mechanism of water release for both structural and zeolitic H2O. Experimental results were interpreted also with the help of structural models obtained by molecular mechanics simulations, offering atomistic insights on the mechanisms at the basis of the observed phenomena
The crystal structures of two organometallic complexes of a new 2,9-diformylphenantroline bis-acylhydrazone hexadentate ligand
No full textMerkel Cell Polyomavirus (MCV) in Buffy Coats of Healthy Blood Donors.
No full textBackground.
Merkel cell polyomavirus (MCV), a DNA tumor virus, has been found to be associated with Merkel cell carcinoma (MCC) and chronic lymphocytic leukaemia (CLL). MCV sequences have also been detected in various normal tissues in tumor affected patients. Immunologic studies have detected MCV antibodies in as many as 80% of healthy blood donors. This high seroprevalence suggests that MCV infection is widespread in humans.
Materials and methods
DNA from buffy coats (n=60) of healthy blood donors was investigated by two PCR rounds, 35 cycles each, for two different MCV Tag regions, nt 571-879 and nt 1709-1846, respectively. To quantify the MCV DNA load, positive samples were further analyzed by RQ-PCR for Tag sequences. To determine the human cell equivalents of each sample under analysis, RQ-PCR assays were carried out simultaneously with the cellular RNase P gene. The specificity of PCR amplified products, 10 amplicons from the MCV Tag regions, were DNA sequenced.
Results
PCR re-amplifications showed that 13 out of 60 (22%) DNA samples were positive for MCV Tag coding sequences. Buffy coats under analysis indicated that the viral DNA copy numbers were very low, ranging from 10 to 100 copies/100,000 cells. The sequencing result of the PCR amplicons, for both strands, nt 571-879 and nt 1709-nt 1846, identified as belonging to the MCV genome, MKL-1 strain.
Conclusions
MCV sequences were detected in buffy coats from healthy blood donors. This result suggests that MCV is able to infect specific blood leukocyte cells, where it remains in a latent/persistent state in the PBMCs of immune-competent individuals. In the long term, viral persistent infection may allow MCV to generate mutants which can participate in the cell transformation process. Indeed, large T antigen MCV deletion mutants have been detected in CLL or integrated into MCC. This oncogenic process, together with the immune impairment of the host and other factors, is a well-known multistep cell transformation mechanism employed by other DNA tumor viruses, such as human papillomaviruses, which are closely related to the Merkel cell polyomavirus.
Acknowledgements
We thank Prof. Tobias Allander, Karolinska Instituten, Stockolm, Sweden, for his generous gift of the recombinant plasmid pMCV-LT.1
Reference
Pancaldi C, Corazzari V, Maniero S, Mazzoni E, Comar M, Martini F, Tognon M. Merkel cell polyomavirus DNA sequences in the buffy coats of healthy blood donors. Blood 2011, 117:7099-7101
Polymorphism rs7214723 in CAMKK1: A new genetic variant associated with cardiovascular diseases
No full textCardiovascular diseases (CVDs) are the leading cause of deaths worldwide. CVDs have a complex etiology due to the several factors underlying its development including environment, lifestyle, and genetics. Given the role of calcium signal transduction in several CVDs, we investigated via PCR-restriction fragment length polymorphism (RFLP) the single nucleotide polymorphism (SNP) rs7214723 within the calcium/calmodulin-dependent kinase kinase 1 (CAMKK1) gene coding for the Ca2+/calmodulin-dependent protein kinase kinase I. The variant rs7214723 causes E375G substitution within the kinase domain of CAMKK1. A cross-sectional study was conducted on 300 cardiac patients. RFLP-PCR technique was applied, and statistical analysis was performed to evaluate genotypic and allelic frequencies and to identify an association between SNP and risk of developing specific CVD. Genotype and allele frequencies for rs7214723 were statistically different between cardiopathic and several European reference populations. A logistic regression analysis adjusted for gender, age, diabetes, hypertension, BMI and previous history of malignancy was applied on cardiopathic genotypic data and no association was found between rs7214723 polymorphism and risk of developing specific coronary artery disease (CAD) and aortic stenosis (AS). These results suggest the potential role of rs7214723 in CVD susceptibility as a possible genetic biomarker
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Bone mass evaluated by calcaneous ultrasound and radial peripheral computed tomography in 726 youngsters
No full textTo compare the results of ultrasound and computed peripheral tomography in evaluating bone mass in a population of normal children. Seven hundred and twenty-six healthy school children (260 males; age 8.3-20.9 y) underwent calcaneous ultrasound and peripheral computed tomography at the ultradistal radius. Broadband ultrasound attenuation (BUA) and areal and volumetric bone mineral density (aBMD and vBMD) were evaluated. The results were compared and correlated among them and with auxological parameters (height, BMI and pubertal stages) using the software package SPSS for Windows. The three variables examined (BUA, aBMD and vBMD) all showed a progressive increase with age and a positive correlation with age, height and BMI. When the population was subdivided according to pubertal stages, all variables showed a progressive increase, the difference being significant when stages 1-2 were compared with stages 4-5. A significant correlation was present among BUA, aBMD and vBMD even if the Pearson correlation coefficient was not high.The similar pattern of BUA, aBMD and vBMD with respect to age, height and pubertal stages indicates that ultrasound could be a reliable method to screen bone mass abnormalities in children. The low correlation coefficient, however, suggests that the methods employed measure different bone parameters. Moreover, the different skeletal locations could also account for these results
Disagio materno e supporto psicologico durante il ricovero ospedaliero del neonato pretermine.
No full textEvolution of host/guest interactions with heating in a palygorskite/methyl red (Maya Red) hybrid composite
No full textAn exceptionally stable hybrid material, fit for possible use as an innovative, cheap and ecologic pigment in the Cultural Heritage and Materials Science fields, can be obtained by grinding and heating palygorskite clay with the methyl red dye (2 wt%).
Due to its multiple analogies with the famed Maya Blue pigment (an ancestor of modern hybrid materials formed by indigo incorporation in palygorskite/sepiolite clay minerals), such a red/purple adduct can be considered an analogous Maya Red composite.
As per its renowned blue predecessor, the chemical and photo-thermal stability observed for this red equivalent is achieved through methyl red diffusion and bonding within the palygorskite tunnels, which occurs after heating or evacuation of a properly ground clay/dye mixture. Specific interactions form inside the host pores between the clay framework and dye reactive groups, contributing to ensure the composite stabilization at different temperatures.
An innovative, in-line coupled TGA-FTIR-GC-MS, synchrotron XRPD and molecular mechanics approach was performed on both pristine palygorskite and the related composite with methyl red with the aim to monitor the development of the interactions formed between the host and the guest while progressively heating. Such a study evidenced that several kinds of bonds can exist and differently affect this complex stability, each characterized by a specific binding energy and subjected to a dynamic but reversible evolution as a function of the magnitude of the heating treatment.
Weak to moderate temperatures (120-300°C) trigger zeolitic H2O loss and methyl red diffusion but do not imply release of Mg-coordinated OH2, which acts as H-bond donor to the dye carboxyl group. More severe heating (300-490°C) causes a two-step structural OH2 loss and triggers a ligand-displacement mechanism which favors straight interactions between octahedral Mg and the dye COOH acceptor atoms (i.e. oxygen).
Reversibility and shift between these different host/guest interactions severely affect the dehydration/rehydration process of the host framework, compared to the pristine clay. Several interrelated phenomena mutually interact in a sort of positive feedback: guest incorporation inside the tunnels prevents structural folding typical of pure palygorskite and modifies the release of both zeolitic H2O and structural OH2, consequently influencing both the nature and the strength of the host/guest interactions. Such a situation is further complicated by the different polymorphs of palygorskite (monoclinic and orthorhombic) showing peculiar and distinct behaviors, which concern both their affinity to form specific bonds with the encapsulated dye and the release of structural OH2 while heating.
Sheltering granted by incorporation in the host pores dramatically enhances methyl red thermal stability, whose degradation is likely to occur at temperatures sensibly higher than those decaying the isolated dye
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