90 research outputs found

    Effect of lactarius piperatus fruiting body maturity stage on antioxidant activity measured by several biochemical assays

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    The effects of fruiting body maturity on antioxidant activity and antioxidants production of the wild mushroom, Lactarius piperatus, were evaluated. Several biochemical assays were used to screen the antioxidant properties: reducing power, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity, inhibition of erythrocytes hemolysis mediated by peroxyl radicals and inhibition of lipid peroxidation using the b-carotene linoleate model system. The amounts of phenols, flavonoids, ascorbic acid, b-carotene and lycopene present in the immature, mature and degraded fruiting bodies were also determined. The highest antioxidant contents and the lowest EC50 values for antioxidant activity were obtained in the mature stage with immature spores

    Trapping the δ isomer of the polyoxometalate-based Keggin cluster with a tripodal ligand

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    We report the synthesis, structural, and electronic characterization of the theoretically predicted, but experimentally elusive δ-isomer of the Keggin polyanion. A family of δ-Keggin polyoxoanions of the general formula, (TEA)HpNaq [H2M12(XO4)O33(TEA)].rH2O where p, q, r = [2,3,8] for 1 and [4,1,4] for 2 were isolated by the reaction of tungstate(VI) and vanadium(V) with triethanolammonium ions (TEAH), acting as a tripodal ligand grafted to the surface of the cluster leading to the entrapment and stabilization of the elusive polyanhionic δ Keggin archetype. The δ-Keggin species were characterized by single-crystal X-ray diffraction, FT-IR, UV-vis, NMR and ESI-MS spectrometry. Electronic structure and structure-stability correlations were evaluated by means of DFT calculations. The compounds exhibited multi-electron transfer and reversible photochromic properties by undergoing single-crystal-to-single-crystal (SC-SC) transformations accompanied with colour changes under ligh

    Paramagnetic moment measurements by nmr. A micro technique

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    A general approach to calculating isotope abundance ratios in mass spectroscopy

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    Pretransplant cytotoxic donor T-cell activity specific to patient HLA class I antigens correlating with mortality after unrelated BMT

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    Unrelated bone marrow transplantation (BMT) is associated with increased post-transplant complication rates, partly because more transplantation antigens are mismatched than in HLA-identical related BMT. We have shown previously that the cytotoxic T-lymphocyte precursor (CTLp) test performed before transplantation specifically detects HLA class I mismatches demonstrating its usefulness for the identification of new HLA class I alleles. In this study we analysed the clinical relevance of the CTLp test in 41 patients who underwent unrelated BMT between 1990 and 1994. All patient-donor pairs were HLA-A, -B, -DR compatible as defined by AB-serology and oligotyping for DR1-14. The host-reactive CTLp test was performed using previously frozen peripheral blood mononuclear cells (PBMC) as stimulators and PHA blasts as target cells. We found 10 CTLp-positive and 31 CTLp-negative patient-donor pairs. Between the two groups there were no significant differences for age, diagnosis, sex, preconditioning and GvHD prophylaxis. The clinical results for the CTLp positive and the CTLp negative transplants were: severe acute GvHD III-IV 67% and 26% (P = 0.0315), transplant-related mortality 60% and 26% (P = 0.0085), and patient survival at 3.5 years 10% and 54% (P = 0.0006). Seven patient-donor pairs were mismatched for HLA-DR and/or -DQ subtypes. Only one of these seven class II mismatched pairs had a positive CTLp test. In the remaining nine CTLp positive pairs the CTL reactivity was directed against HLA-A, -B or -C antigens, revealing a statistically significant (P < 0.005) correlation between the CTLp frequency and HLA class I matching. In conclusion, the CTLp test helped to select optimally matched bone marrow donors and was particularly useful in association with high resolution oligotyping for DR- and DQ-subtypes for precise matching of both classes of HLA antigens
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