Spondyloarthritis after bariatric surgery: is there a link?

Presently, bariatric surgery is considered the most effective treatment for reducing excess body weight and maintaining weight loss in severely obese. On the other hand, several early and late complications have been described after this procedure. This article reports two patients who developed a spondyloarthritis-like syndrome after bariatric surgery. Probable etiopathogenic mechanisms are discussed.     

Antigenotoxicity of artepillin C in vivo evaluated by the micronucleus and comet assays

Artepillin C (3,5‐diprenyl‐p‐coumaric acid), a major compound found in Brazilian green propolis and Baccharis dracunculifolia, shows anti‐inflammatory, antibacterial, antiviral, antioxidant and antitumoral activities, among others. The aim of this study was to evaluate the genotoxic potential of artepillin C and its ability to prevent the chemically induced chromosome breakage or loss and the primary DNA damage using the micronucleus and comet assays in male Swiss mice, respectively. The animals were treated by gavage with different doses of artepillin C (0.4, 0.8 and 1.6 mg kg^?1 b.w.). For the antigenotoxicity assays, the different doses of artepillin C were administered simultaneously to doxorubicin (DXR; micronucleus test; 15 mg kg^?1 b.w.) and to methyl methanesulfonate (MMS; comet assay; 40 mg kg^?1 b.w.). The results showed that artepillin C itself was not genotoxic in the mouse micronucleus and comet assays. In the animals treated with artepillin C and DXR, the number of micronucleated reticulocytes was significantly lower in comparison with the animals treated only with DXR. Regarding antigenotoxicity, artepillin C at the tested doses significantly reduced the extent of DNA damage in liver cells induced by MMS. Copyright © 2011 John Wiley & Sons, Ltd.     

Inhibitory effect of pisosterol on human glioblastoma cell lines with C‐MYC amplification

Despite the remarkable progress in the characterization of the molecular pathogenesis of glioblastoma multiforme (GBM), these tumors remain incurable and, in most cases, refractory to aggressive cytotoxic treatments. We conducted a morphological and cytogenetic study in two GBM cell lines (U343 and AHOL1), before and after treatment with pisosterol (at 0.5, 1.0 and 1.8 µg ml^?1), a triterpene isolated from the fungus Pisolithus tinctorius. No significant alteration was observed in the morphology and frequency of chromosomal abnormalities in the cell lines analyzed after treatment with pisosterol. Using fluorescence in situ hybridization analysis with a locus‐specific probe for C‐MYC showed that 72% of U343 and 65% of AHOL1 cells contained more than two alleles of C‐MYC before treatment. After treatment, no effects were detected at lower concentrations of pisosterol (0.5 and 1.0 µg ml^?1). However, at 1.8 µg ml^?1 of pisosterol, only 33% of U343 cells and 15% of AHOL1 cells presented more than two fluorescent signals, suggesting that pisosterol blocks the cells with gene amplification. Cells that do not show a high degree of C‐MYC gene amplification have a less aggressive and invasive behavior and are easy targets for chemotherapy. Therefore, further studies are needed to examine the use of pisosterol in combination with conventional anti‐cancer therapy. Copyright © 2010 John Wiley & Sons, Ltd.     

Simultaneous quantitation of levodopa and 3-O-methyldopa in human plasma by HPLC-ESI-MS/MS: application for a pharmacokinetic study with a levodopa/benserazide formulation

A sensitive and simple method was developed for the quantitation of levodopa and its metabolite 3-O-methyldopa, in human plasma, after oral administration of tablet formulations containing levodopa (200 mg) and benserazide (50 mg). The analytes were extracted by a protein precipitation procedure, using carbidopa as an internal standard. A mobile phase consisting of 0.2% formic acid and acetonitrile (94:6, v/v) was used and chromatographic separation was achieved using ACE C₁₈ column (50 mm × 4.6 mm i.d.; 5 μm particle size). Selected reaction monitoring was performed using the fragmentation transitions m/z 198 → m/z 107, m/z 212 → m/z 166 and m/z 227 → m/z 181 for levodopa, 3-O-methyldopa and carbidopa, respectively. Calibration curves were constructed over the range 50.0-6000.0 ng/mL for levodopa and 25.0-4000.0 ng/mL for 3-O-methyldopa. The method shown to be specific, precise, accurate and provided recovery rates higher than 85% for all analytes. No matrix effect was detected in the samples. The validated method was applied in a pharmacokinetic study with a levodopa/benserazide tablet formulation in healthy volunteers.     

Antinociceptive activity of (-)-(2S,6S)-(6-ethyl-tetrahydropyran-2-yl)-formic acid on acute pain in mice

Pain is a major cause of distress, both physical and psychological. There is a continuous search for new pharmacologically active analgesic agents with minor adverse effects. Recently, the synthesis of (-)-(2S,6S)-(6-ethyl-tetrahydropyran-2-yl)-formic acid [tetrahydropyran derivative (TD)] was described. The objective of this study was to investigate antinociceptive effects of TD. Its activity was compared with the activity of morphine. The effects of TD and morphine were evaluated in models of inflammatory and noninflammatory pain. TD (6-1200 μmol/kg, intraperitoneally) significantly reduced the nociceptive effects induced by acetic acid or formalin in mice. TD also demonstrated an antinociceptive effect in the tail-flick and hot-plate model. The opioid receptor antagonist, naloxone (at 15 μmol/kg, intraperitoneally), reversed the antinociceptive activity of TD in all the models evaluated. Morphine and TD induced tolerance in mice. However, the onset of tolerance to TD was delayed compared with that induced by morphine. These results indicate that TD develops significant antinociceptive activity and, at least part of its effects seems to be mediated by the opioid system.     

Caco-2 cells cytotoxicity of nifuroxazide derivatives with potential activity against Methicillin-resistant Staphylococcus aureus (MRSA)

It is important to determine the toxicity of compounds and co-solvents that are used in cell monolayer permeability studies to increase confidence in the results obtained from these in vitro experiments. This study was designed to evaluate the cytotoxicity of new nifuroxazide derivatives with potential activity against Methicillin-resistant Staphylococcus aureus (MRSA) in Caco-2 cells to select analogues for further in vitro permeability analyses. In this study, nitrofurantoin and nifuroxazide, in addition to 6 furanic and 6 thiophenic nifuroxazide derivatives were tested at 2, 4, 6, 8 and 10 μg/mL. In vitro cytotoxicity assays were performed according to the MTT (methyl tetrazolium) assay protocol described in ISO 10993-5. The viability of treated Caco-2 cells was greater than 83% for all tested nitrofurantoin concentrations, while those treated with nifuroxazide at 2, 4 and 6 μg/mL had viabilities greater than 70%. Treatment with the nifuroxazide analogues resulted in viability values greater than 70% at 2 and 4 μg/mL with the exception of the thiophenic methyl-substituted derivative, which resulted in cell viabilities below 70% at all tested concentrations. Caco-2 cells demonstrated reasonable viability for all nifuroxazide derivatives, except the thiophenic methyl-substituted compound. The former were selected for further permeability studies using Caco-2 cells.     

Gemcitabine: a critical nucleoside for cancer therapy

Gemcitabine (dFdC, 2',2'-difluorodeoxycytidine) is a deoxycytidine nucleoside analogue of deoxycytidine in which two fluorine atoms have been inserted into the deoxyribose ring. Like other nucleoside analogues, gemcitabine is a prodrug. It is inactive in its original form, and depends on the intracellular machinery to gain pharmacological activity. What makes gemcitabine different from other nucleoside analogues is that it is actively transported across the cell membrane, it is phosphorylated more efficiently and it is eliminated at a slower rate. These differences, together with self-potentiation mechanisms, masked DNA chain termination and extensive inhibitory efficiency against several enzymes, are the source of gemcitabine's cytotoxic activity against a wide variety of tumors. This unique combination of metabolic properties and mechanistic characteristics is only found in very few other anticancer drugs, and both the FDA and the EMEA have already approved its use for clinical purposes, for the treatment of several types of tumors. In spite of the promising results associated with gemcitabine, the knowledge of its mode of action and of the enzymes it interacts with is still not fully documented. In this article we propose to review all these aspects and summarize the path of gemcitabine inside the cell.     

Practical considerations for conducting ecotoxicity test methods with manufactured nanomaterials: what have we learnt so far?

This review paper reports the consensus of a technical workshop hosted by the European network, NanoImpactNet (NIN). The workshop aimed to review the collective experience of working at the bench with manufactured nanomaterials (MNMs), and to recommend modifications to existing experimental methods and OECD protocols. Current procedures for cleaning glassware are appropriate for most MNMs, although interference with electrodes may occur. Maintaining exposure is more difficult with MNMs compared to conventional chemicals. A metal salt control is recommended for experiments with metallic MNMs that may release free metal ions. Dispersing agents should be avoided, but if they must be used, then natural or synthetic dispersing agents are possible, and dispersion controls essential. Time constraints and technology gaps indicate that full characterisation of test media during ecotoxicity tests is currently not practical. Details of electron microscopy, dark-field microscopy, a range of spectroscopic methods (EDX, XRD, XANES, EXAFS), light scattering techniques (DLS, SLS) and chromatography are discussed. The development of user-friendly software to predict particle behaviour in test media according to DLVO theory is in progress, and simple optical methods are available to estimate the settling behaviour of suspensions during experiments. However, for soil matrices such simple approaches may not be applicable. Alternatively, a Critical Body Residue approach may be taken in which body concentrations in organisms are related to effects, and toxicity thresholds derived. For microbial assays, the cell wall is a formidable barrier to MNMs and end points that rely on the test substance penetrating the cell may be insensitive. Instead assays based on the cell envelope should be developed for MNMs. In algal growth tests, the abiotic factors that promote particle aggregation in the media (e.g. ionic strength) are also important in providing nutrients, and manipulation of the media to control the dispersion may also inhibit growth. Controls to quantify shading effects, and precise details of lighting regimes, shaking or mixing should be reported in algal tests. Photosynthesis may be more sensitive than traditional growth end points for algae and plants. Tests with invertebrates should consider non-chemical toxicity from particle adherence to the organisms. The use of semi-static exposure methods with fish can reduce the logistical issues of waste water disposal and facilitate aspects of animal husbandry relevant to MMNs. There are concerns that the existing bioaccumulation tests are conceptually flawed for MNMs and that new test(s) are required. In vitro testing strategies, as exemplified by genotoxicity assays, can be modified for MNMs, but the risk of false negatives in some assays is highlighted. In conclusion, most protocols will require some modifications and recommendations are made to aid the researcher at the bench.     

Development and validation of a gas chromatography-mass spectrometry method for determination of deoxynivalenol and its metabolites in human urine

The determination of deoxynivalenol (DON) and its metabolites such as deepoxy-deoxynivalenol (DOM-1) in human urine is complicated due its low levels (ng/mL) and the complexity of the matrix. A gas chromatography-mass spectrometry method was optimized and validated for the confirmation analysis of DON and its metabolites in urine samples using 13C isotopic-labeled DON as internal standard. In the sample preparation the type and amount of β-glucuronidase for enzymatic hydrolysis was investigated as well as the cleanup procedure, being compared the immunoaffinity column with solid-phase extraction (SPE). As far as we know, SPE C18 cleanup procedure was applied for the first time in the analysis of DON and its metabolites in human urine. Using this analytical methodology the detection and quantification limits achieved ranged from 0.06 to 0.30 ng/mL and from 0.2 to 1.0 ng/mL, respectively. Recoveries were higher than 73% for fortification levels between 25 and 100 ng/mL and repeatability were lower than 13%. The natural occurrence of DON and its metabolites in human urine samples from the north zone of Portugal was studied. Free DON was detected in 15% of the samples whereas total (free+conjugated) DON was detected in 69% of the samples. Deepoxy-deoxynivalenol, 3-acetyldeoxynivalenol and 15-acetyldeoxynivalenol were not detected in any of the samples analyzed.