Role of anti-cyclic citrullinated peptide antibodies in discriminating patients with rheumatoid arthritis from patients with chronic hepatitis C infection-associated polyarticular involvement

This study was performed to assess the utility of anti-cyclic citrullinated peptide (anti-CCP) antibodies in distinguishing between patients with rheumatoid arthritis (RA) and patients with polyarticular involvement associated with chronic hepatitis C virus (HCV) infection. Serum anti-CCP antibodies and rheumatoid factor (RF) were evaluated in 30 patients with RA, 8 patients with chronic HCV infection and associated articular involvement and 31 patients with chronic HCV infection without any joint involvement. In addition, we retrospectively analysed sera collected at the time of first visit in 10 patients originally presenting with symmetric polyarthritis and HCV and subsequently developing well-established RA. Anti-CCP antibodies and RF were detected by commercial second-generation anti-CCP2 enzyme-linked immunosorbent assay and immunonephelometry respectively. Anti-CCP antibodies were detected in 23 of 30 (76.6%) patients with RA but not in patients with chronic HCV infection irrespective of the presence of articular involvement. Conversely, RF was detected in 27 of 30 (90%) patients with RA, 3 of 8 (37.5%) patients with HCV-related arthropathy and 3 of 31 (9.7%) patients with HCV infection without joint involvement. Finally, anti-CCP antibodies were retrospectively detected in 6 of 10 (60%) patients with RA and HCV. This indicates that anti-CCP antibodies can be useful in discriminating patients with RA from patients with HCV-associated arthropathy.     

Antioxidant and pro-oxidant effects of tannins in digestive cells of the freshwater mussel Unio tumidus

Bivalve molluscs, particularly mussels, are sensitive biomarkers of aquatic ecosystem pollution. The tannins, water-soluble plant polyphenols, may play an important role in this environment and, mainly as a consequence of interaction with pollutants, their toxicity may change. We studied three naturally occurring compounds, tannic acid, ellagic acid and gallic acid, for their ability to modulate DNA damage produced by these tannins alone and in the presence of the oxidative stress inducer H(2)O(2), in cells of the digestive gland of mussels (Unio tumidus). After the treatment of the cells with polyphenols at different concentrations (1, 5, 15, 30, 60, 80, 100, 120, 180, 240 microM) and with hydrogen peroxide in the range of 0.04 and 0.1mM, single-strand breaks (ssb) in DNA were investigated, using the comet assay. The ability of phenolic acids to decrease DNA damage through their antioxidant properties was also assessed. The results show that the phenols, which are known as antioxidative agents, could also act as pro-oxidants. They induced ssb in DNA of the digestive gland at concentrations higher that 10 microM, but lower doses (1 and 5 microM) did not contribute to the DNA damage. This study was also designed to evaluate the protective effect of these tannins against H(2)O(2)-mediated DNA damage in the cells. In this treatment, the two concentrations (1 and 5 microM) significantly decreased the amount of lesions induced by H(2)O(2) (0.04 and 0.1mM). In conclusion, our results demonstrate that antioxidative properties of tannins may change to pro-oxidative activities at the higher concentrations. This suggests that the biologic actions of these compounds may be rather complicated.     

The polytetrafluoroethylene-covered stent: a device with multiple potential advantages

The polytetrafluoroethylene (PTFE)-covered stent has emerged in the past year as a device with multiple potential advantages. Its structure (a sandwich composed of a layer of PTFE membrane between two stents) makes this the ideal tool for treating coronary ruptures, and for excluding coronary aneurysms. Furthermore, this device may be useful in the treatment of aortocoronary vein graft stenosis. In the present review, the authors summarize experiences with covered stents, and focus attention on available data on the implantation of PTFE-covered stents in human beings to treat coronary ruptures, aneurysms and aortocoronary vein graft stenosis.     

Reduction of 1,4-quinone and ubiquinones by hydrogen atom transfer under UVA irradiation

1,4-Benzoquinone, coenzyme Q 0 and Q 10 were reacted with a series of hydrogen donors in the ESR cavity in the presence or absence of UVA irradiation. The signals of the radicals generated from the hydrogen donors or of those of the semiquinones were detected. The reaction mechanism was interpreted by a hydrogen atom transfer instead of the usual electron transfer mechanism on the basis of the redox potentials of the reactants and the Marcus theory. The hydrogen atom transfer is explained by the excited triplet state of quinones, which, on the basis of quantum mechanic calculations, may be reached even under visible light. In some cases, hydrogen atom transfer was also observed without irradiation, although to a lesser extent.     

Direct identification of tyrosine 474 as a regulatory phosphorylation site for the Akt protein kinase

Understanding the regulation of Akt has been of major interest for elucidating the control of normal cellular physiology as well as malignant transformation. The paradigm for activation of Akt involves phosphatidylinositol 3-kinase-dependent membrane localization followed by activating phosphorylation of Thr-308 and Ser-473. Many of the activating signals for Akt involve the stimulation of receptor and non-receptor tyrosine kinases, and the most potent activator known is the tyrosine phosphatase inhibitor pervanadate, highlighting a possible role for tyrosine phosphorylation in the regulation of the enzyme. In this study we show that activation of Akt by pervanadate or serum is associated with tyrosine phosphorylation of Akt. In addition, in SKOV3 ovarian carcinoma cells that exhibit high basal levels of Akt activity, Akt was tyrosine-phosphorylated in the basal state, and this phosphorylation was further enhanced by both pervanadate and insulin-like growth factor-1. We have used NH(2)-terminal sequencing and phosphate release analysis to directly identify Tyr-474 as the site of tyrosine phosphorylation. Substitution of Tyr-474 with phenylalanine abolished tyrosine phosphorylation of Akt and resulted in up to 55% inhibition of Akt activation, indicating phosphorylation at Tyr-474 is required for full activation of the kinase. Our data identifies a novel regulatory mechanism for this pleiotropic enzyme that may be applicable to the AGC family of protein kinases given the conserved nature of the COOH-terminal hydrophobic motif containing Tyr-474.     

Synthesis and characterization of new copper(I) complexes containing 4-(diphenylphosphane)benzoic acid and "scorpionate" ligands with "in vitro" superoxide scavenging activity

New copper(I) complexes have been synthesised from the reaction of CuCl with 4-(diphenylphosphane)benzoic acid and lithium tris(1H-pyrazol-1-yl)methanesulfonate, Li(SO(3))C(pz)(3), sodium hydrotris(3-trifluoromethyl-1H-pyrazol-1-yl)borate, NaHB[3-(CF(3))pz](3), potassium dihydrobis(1H-1,2,4-triazol-1-yl)borate, KH(2)B(tz)(2), hydrotris(1H-1,2,4-triazol-1-yl)borate, KHB(tz)(3), sodium hydrotris(1H-pyrazol-1-yl)borate, NaHB(pz)(3), potassium hydrotris(3,5-dimethyl-1H-pyrazol-1-yl)borate KHB(3,5-Me(2)Pz)(3) or potassium hydrotris(4-bromo-1H-pyrazol-1-yl)borate KHB(4-Brpz)(3). The complexes obtained have been characterized by elemental analyses and FT-IR in the solid state, and by NMR (1H and 31P[(1)H]) spectroscopy and conductivity measurements in solution. The solution data are consistent with partial dissociation of the sterically hindered complexes by way of breaking of Cu-P and Cu-N bonds. Electrospray mass spectrometry has been used to investigate the relative properties of the 4-(diphenylphosphane)benzoic acid and of the "scorpionate" ligands towards copper(I) ions. Chemiluminescence technique was used to evaluate the superoxide scavenging activity of these new copper complexes.     

Effects of mercury on microbial biomass and enzyme activities in soil

Mercury (Hg) is a persistent soil pollutant that affects soil microbial activity. We monitored the changes in soil microbial biomass and activity of enzymes, including alkaline phosphatase, arylsulfatase, fluorescein diacetate (FDA) hydrolytic activity, and o-diphenol oxidase (o-DPO) in three soils contaminated with different concentrations of Hg. Increasing levels of Hg, from 0.5 to 10 μmol/g of dried soil, generally depressed microbial activity; however, the effects of Hg on soil microbial activity depended on soil type and composition, particularly organic matter content. o-DPO was less affected by Hg than the other three enzymes tested. Our results indicate that the analysis of microbial biomass content and soil-enzyme activities may be used to predict the soil quality contaminated with Hg.     

Effect of three diaryl tellurides, and an organoselenium compound in trout erythrocytes exposed to oxidative stress in vitro

Previous literature reports have demonstrated that nucleated trout erythrocytes in conditions of oxidative stress are subjected to DNA and membrane damage, and inactivation of glutathione peroxidase. The present study was undertaken to evaluate the ability of three diaryl tellurides and the organoselenium compound ebselen to protect trout (Salmo irideus) erythrocytes against oxidative stress, induced thermally and by a variation of pH. The antioxidant ability of these molecules was evaluated through chemiluminescence. Impairment of DNA was assessed using the comet assay, a rapid and sensitive single cell gel electrophoresis technique, used to detect primary DNA damage in individual cells. At low concentrations (<10 microM), all the compounds used presented a protective effect on DNA damage without altering the hemolysis rate. In higher concentrations, they accelerated the hemolysis rate and two of the diaryl tellurides were strongly genotoxic.