113 research outputs found

    Candida albicans mannoprotein influences the biological function of dendritic cells.

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    Cell wall components of fungi involved in induction of host immune response are predominantly proteins and glycoproteins, the latter being mainly mannoproteins (MP). In this study we analyse the interaction of the MP from Candida albicans (MP65) with dendritic cells (DC) and demonstrate that MP65 stimulates DC and induces the release of TNF-alpha, IL-6 and the activation of IL-12 gene, with maximal value 6 h post treatment. MP65 induces DC maturation by increasing costimulatory molecules and decreasing CD14 and FcgammaR molecule expression. The latter effect is partly mediated by toll-like receptor 2 (TLR2) and TLR4, and the MyD88-dependent pathway is involved in the process. MP65 enables DC to activate T cell response, its protein core is essential for induction of T cell activation, while its glycosylated portion primarily promotes cytokine production. The mechanisms involved in induction of protective response against C. albicans could be mediated by the MP65 antigen, suggesting that MP65 may be a suitable candidate vaccine

    Selectively measuring π back-donation in gold(I) complexes by NMR spectroscopy

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    Even though the Dewar-Chatt-Duncanson model has been successfully used by chemists since the 1950s, no experimental methodology is yet known to unambiguously estimate the constituents (donation and back-donation) of a metal-ligand interaction. It is demonstrated here that one of these components, the metal-to-ligand π back-donation, can be effectively probed by NMR measurements aimed at determining the rotational barrier of a C-N bond (ΔHr (≠) ) of a nitrogen acyclic carbene ligand. A large series of gold(I) complexes have been synthesized and analyzed, and it was found that the above experimental observables show an accurate correlation with back-donation, as defined theoretically by the appropriate charge displacement originated upon bond formation. The proposed method is potentially of wide applicability for analyzing the ligand effect in metal catalysts and guiding their design

    Immunogenetic profiling to predict risk of invasive fungal diseases : where are we now?

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    Invasive fungal diseases remain nowadays life-threatening conditions affecting multiple clinical settings. The onset of these diseases is dependent on numerous factors, of which the "immunocompromised" phenotype of the patients is the more often acknowledged. However, and despite comparable immune dysfunction, not all patients are ultimately susceptible to disease, suggesting that additional risk factors, likely of genetic nature, may also be important. In the last years, genetic variants in several immune-related genes have also been proposed as major determinants of the susceptibility pattern of high-risk patients to invasive fungal diseases. Altogether, these findings highlighted the crucial significance of the individual genetic make-up in defining susceptibility to infection, providing a compelling rationale for the introduction of the immunogenetic profile as a risk prediction measure that may ultimately help to guide clinicians in the use of prophylaxis and preemptive fungal therapy in high-risk patients.Ricerca sulla Fibrosi Cistica (Project number FFC#21/2010)Fundação para a Ciência e a Tecnologia (FCT) SFRH/BD/65962/2009, SFRH/BPD/46292/200

    Toward accurate QM/MM reaction barriers with large QM regions using domain based pair natural orbital coupled cluster theory

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    The hydroxylation reaction catalyzed by p-hydroxybenzoate hydroxylase and the Baeyer–Villiger reaction catalyzed by cyclohexanone monooxygenase are investigated by means of quantum mechanical/molecular mechanical (QM/MM) calculations at different levels of QM theory. The geometries of the stationary points along the reaction profile are obtained from QM/MM geometry optimizations, in which the QM region is treated by density functional theory (DFT). Relative energies are determined from single-point QM/MM calculations using the domain-based local pair natural orbital coupled cluster DLPNO-CCSD(T) method as QM component. The results are compared with single-point DFT/MM energies obtained using popular density functionals and with available experimental and computational data. It is found that the choice of the QM method strongly affects the computed energy profiles for these reactions. Different density functionals provide qualitatively different energy barriers (variations of the order of 10 kcal/mol in both reactions), thus limiting the confidence in DFT/MM computational predictions of energy profiles. On the other hand, the use of the DLPNO-CCSD(T) method in conjunction with large QM regions and basis sets makes it possible to achieve high accuracy. A critical discussion of all the technical aspects of the calculations is given with the aim of aiding computational chemists in the application of the DLPNO-CCSD(T) methodology in QM/MM calculations

    Is minor salivary gland biopsy more than a diagnostic tool in primary Sjorgren's syndrome? Association between clinical, histopathological, and molecular features: A retrospective study

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    Objectives: Several histological scoring systems, including the focus score, performed in minor salivary glands (MSGs) by hematoxylin-eosin (H&E) staining, have been employed in clinical practice to assess the inflammatory infiltrate and provide the diagnosis of primary Sjorgren's syndrome (pSS). Aims of this study were to integrate different scoring systems and identify potential differences in the molecular profile of lymphoid cytokines related to germinal center (GC) formation and clinical subsets in pSS. Methods: Overall, 104 pSS patients and 40 subjects with sicca non-pSS were retrospectively evaluated. MSG biopsies were evaluated by H&E and immunofluorescence to assess histological pattern, Chisholm and Mason grading system, Tarpley score, a grading for the severity of inflammatory infiltrate, T-/B-cell segregation, and the presence of GC. MSGs from 50 pSS patients and 30 sicca non-pSS patients were processed by real-time PCR to assess LTα, LTβ, BAFF, CXCR4, CXCL12, CXCR5, CXCL13, CCR7, CCL19, and CCL21. Results: GCs presence was associated with anti-Ro/SSA and anti-La/SSB antibodies, hypergammaglobulinemia, salivary gland swelling, higher Tarpley score and focus score, and extraglandular involvement but, at multivariate analysis, only extraglandular involvement was independently associated to GC. pSS patients displayed higher level of all cytokines compared to those with sicca symptoms. GC+ pSS patients displayed higher level of all cytokines compared to those GC-. Conclusions: Our study demonstrates that different histopathological patterns, including GC presence, reflect different cytokine expression and different clinical subsets. We believe that the combined immunofluorescence/molecular approach in MSGs would help to tailor diagnostic and therapeutic approach for different subsets of pSS patients

    Primary breast lymphomas: a multicentric experience

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    Background: The Primary Breast Lymphomas (PBL) represent 0,38-0,70% of all non-Hodgkin lymphomas (NHL), 1,7-2,2% of all extranodal NHL and only 0,04-0,5% of all breast cancer. Most frequent PBLs are the diffuse large B cell lymphomas; in any case-reports MALT lymphomas lack or are a rare occurrence. Their incidence is growing. From 1880 (first breast resection for "lymphadenoid sarcoma" carried out by Gross) to the recent past the gold standard treatment for such diseases was surgery. At present such role has lost some of its importance, and it is matter of debate. Methods: Twenty-three women affected by PBL underwent surgery. Average age was 63 years (range: 39-83). Seven suffered of hypothyroidism secondary to autoimmune thyroiditis. Fourteen patients underwent mastectomy, nine patients received quadrantectomy (average neoplasm diameter: 1,85 cm, range: 1,1-2,6 cm). In 10 cases axillary dissection was carried out. Pathologic examination revealed 16 diffuse large B cell lymphomas and 7 MALT lymphomas. Results: Seven patients in the mastectomy group had a recurrence (50%), and all of them with diffuse large B cell lymphomas at stage II. Two of these had not received chemotherapy. No patient undergoing quadrantectomy had recurrence. In the mastectomy group disease free survival (DFS) at 5 and 10 years was 57 and 50%. Overall survival (OS) at 5 and 10 years was 71.4% and 57.1% respectively. All recurrences were systemic. DFS and OS at 5 and 10 years was 100% in the quadrantectomy group. In the patients with recurrence mortality was 85.7%. For stage IE DFS and OS at 5 and 10 years were 100%. For stage II DFS at 10 years was 62.5% and 56.2% respectively; OS at 5 and 10 years was 75% and 62.5% respectively. For MALT lymphomas DFS and OS at 5 and 10 years were 100%. For diffuse large B cell lymphomas DFS at 5 and 10 years was 62.5% and 56.2% respectively; OS at 5 and 10 years was 75% and 62,5% respectively. Conclusions: The role of surgery in this disease should be limited to get a definitive diagnosis while for the staging and the treatment CT scan and chemio/radioterapy are repectively mandatory. MALT PBLs have a definitely better prognosis compared to large B cell lymphomas. The surgical treatment must always be oncologically radical (R0); mastectomy must not be carried out as a rule, but only when tissue sparing procedures are not feasible. Axillary dissection must always be performed for staging purposes, so avoiding the risk of under-staging II o IE, due to the possibility of clinically silent axillary node involvement

    The furan microsolvation blind challenge for quantum chemical methods: First steps

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    © 2018 Author(s). Herein we present the results of a blind challenge to quantum chemical methods in the calculation of dimerization preferences in the low temperature gas phase. The target of study was the first step of the microsolvation of furan, 2-methylfuran and 2,5-dimethylfuran with methanol. The dimers were investigated through IR spectroscopy of a supersonic jet expansion. From the measured bands, it was possible to identify a persistent hydrogen bonding OH-O motif in the predominant species. From the presence of another band, which can be attributed to an OH-π interaction, we were able to assert that the energy gap between the two types of dimers should be less than or close to 1 kJ/mol across the series. These values served as a first evaluation ruler for the 12 entries featured in the challenge. A tentative stricter evaluation of the challenge results is also carried out, combining theoretical and experimental results in order to define a smaller error bar. The process was carried out in a double-blind fashion, with both theory and experimental groups unaware of the results on the other side, with the exception of the 2,5-dimethylfuran system which was featured in an earlier publication

    Blue honeysuckle fruit (Lonicera caerulea L.) from eastern Russia: phenolic composition, nutritional value and biological activities of its polar extracts

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    In the present work we conducted a comprehensive chemical analysis of blue honeysuckle (Lonicera caerulea) spontaneously growing in eastern Russia. HPLC-DAD-ESI/MS analysis showed cyanidin-3-glucoside as the major constituent among phenolics, while nutritional analysis revealed fibre, protein, calcium and magnesium as the most important macro- and micronutrients, respectively. Fatty acid composition was dominated by polyunsaturated fatty acids, linoleic acid being the most abundant. Furthermore, we evaluated several in vitro biological activities such as antioxidant, antimicrobial, antiproliferative, wound healing and immunomodulatory effects of blue honeysuckle aqueous and ethanolic extracts that are often incorporated in food and nutraceutical preparations. While the fruit extracts were revealed to be potent radical scavengers with significant inhibition of ABTS radical, thus confirming the literature data, their inhibitory effects against microbial pathogens and tumor cell lines were negligible. The fruit aqueous extract did not show toxicity to human fibroblasts, but 24 h treatment with 150–200 μg per mL of extract slightly enhanced the cell migration when tested by scratched wound assay. Worth mentioning was the inhibitory effect displayed by the blue honeysuckle fruit aqueous extract on human lymphocytes

    A Combined Spectroscopic and Computational Study on the Mechanism of Iron-Catalyzed Aminofunctionalization of Olefins Using Hydroxylamine Derived N-O Reagent as the "Amino" Source and "Oxidant".

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    Herein, we study the mechanism of iron-catalyzed direct synthesis of unprotected aminoethers from olefins by a hydroxyl amine derived reagent using a wide range of analytical and spectroscopic techniques (Mössbauer, Electron Paramagnetic Resonance, Ultra-Violet Visible Spectroscopy, X-ray Absorption, Nuclear Resonance Vibrational Spectroscopy, and resonance Raman) along with high-level quantum chemical calculations. The hydroxyl amine derived triflic acid salt acts as the "oxidant" as well as "amino" group donor. It activates the high-spin Fe(II) (St = 2) catalyst [Fe(acac)2(H2O)2] (1) to generate a high-spin (St = 5/2) intermediate (Int I), which decays to a second intermediate (Int II) with St = 2. The analysis of spectroscopic and computational data leads to the formulation of Int I as [Fe(III)(acac)2-N-acyloxy] (an alkyl-peroxo-Fe(III) analogue). Furthermore, Int II is formed by N-O bond homolysis. However, it does not generate a high-valent Fe(IV)(NH) species (a Fe(IV)(O) analogue), but instead a high-spin Fe(III) center which is strongly antiferromagnetically coupled (J = -524 cm-1) to an iminyl radical, [Fe(III)(acac)2-NH·], giving St = 2. Though Fe(NH) complexes as isoelectronic surrogates to Fe(O) functionalities are known, detection of a high-spin Fe(III)-N-acyloxy intermediate (Int I), which undergoes N-O bond cleavage to generate the active iron-nitrogen intermediate (Int II), is unprecedented. Relative to Fe(IV)(O) centers, Int II features a weak elongated Fe-N bond which, together with the unpaired electron density along the Fe-N bond vector, helps to rationalize its propensity for N-transfer reactions onto styrenyl olefins, resulting in the overall formation of aminoethers. This study thus demonstrates the potential of utilizing the iron-coordinated nitrogen-centered radicals as powerful reactive intermediates in catalysis
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