Stereoselective determination of midodrine and desglymidodrine in culture medium: Application to a biotransformation study employing endophytic fungi

A CE method was developed and validated for the stereoselective determination of midodrine and desglymidodrine in Czapek culture medium to be applied to a stereoselective biotransformation study employing endophytic fungi. The electrophoretic analyses were performed using an uncoated fused-silica capillary and 70 mmol/L sodium acetate buffer solution (pH 5.0) containing 30 mmol/L heptakis (2, 3, 6-tri-O-methyl)-beta-CD as running electrolyte. The applied voltage and temperature used were 15 kV and 15 C, respectively. The UV detector was set at 200 nm. The sample preparation was carried out by liquid-liquid extraction using ethyl acetate as extractor solvent. The method was linear over the concentration range of 0.1-12 mu g/mL for each enantiomer of midodrine and desglymidodrine (r >= 0.9975). Within-day and between-day precision and accuracy evaluated by RSDs and relative errors, respectively, were lower than 15% for all analytes. The method proved to be robust by a fractional factorial design evaluation. The validated method was used to assess the midodrine biotransformation to desglymidodrine by the fungus Phomopsis sp. (TD2), which biotransformed 1.1% of (-)-midodrine to (-)-desglymidodrine and 6.1% of (+)-midodrine to (+)-desglymidodrine.

In vitro and in vivo antileishmanial activities of a Brazilian green propolis extract

The in vitro antileishmanial activity of Brazilian green propolis hydroalcoholic extract (BPE) were carried out on Leishmania (Viannia) braziliensis against both promastigote (doses ranging from 1 to 750 mu g mL(-1)) and amastigote (10, 100, and 250 mu g mL(-1)) assays in comparison with the positive (amphotericin B) and negative (dimethyl sulfoxide at 1% in physiologic solution) control groups. BPE displayed in vitro antileishmanial activities against promastigote forms of the parasite (p<0.05). However, it was inactive against its amastigote ones. In the in vitro cytotoxicity assay against Vero cells, BPE showed no cytotoxicity in the maximum doses tested. The high-performance liquid chromatography analysis allowed the identification of caffeic acid, p-coumaric acid, aromadendrine-4`-methyl-ether, 3-prenyl-p-coumaric acid (drupanin), and 3,5-diprenil-p-cumarico acid (artepillin C) as major compounds of BPE. In the in vivo assay, using a Balb/C lineage of Mus musculus male mice, groups of ten animals each were treated (1.5 mg kg day(-1)) with BPE orally (group 1), BPE topically (group 2), BPE orally and topically (group 3), and glucantime (group 4), using NaCl 0.9% (group 5) as the negative control group. Groups 1, 2, and 3 displayed a decrease on lesion development, after 90 days of treatment, by 78.6%, 84.3%, and 90.0%, respectively, while the glucantime-treated group showed 57.7% of decrease, all in comparison with the negative control group. It is the first time that the in vivo antileishmanial activity has been reported for Brazilian green propolis.

Effect of the dibenzylbutyrolactone lignan (-)-hinokinin on doxorubicin and methyl methanesulfonate clastogenicity in V79 Chinese hamster lung fibroblasts

The dibenzylbutyrolactone lignan (-)-hinokinin (HK) was obtained by partial synthesis from (-)-cubebin, isolated from the dry seeds of the pepper, Piper cubeba. In view of the trypanocidal activity of HK and its potential as a lead compound for drug development, evaluation of its possible genotoxic activity is required. We have tested HK for possible genotoxicity and evaluated the compound`s effect on the activity of the clastogens doxorubicin (DXR) and methyl methanesulfonate (MMS) in the micronucleus (MN) assay with Chinese hamster lung fibroblast V79 cells. HK alone did not induce MN, at concentrations up to 128 mu M. In combined treatments, HK reduced the frequency of MN induced by MMS. With respect to DXR, HK exerted a protective effect at lower concentrations, but at higher concentrations it potentiated DXR clastogenicity. (C) 2010 Elsevier B.V. All rights reserved.

Eudesmanolides and Methyl Ester Derivatives from Dimerostemma arnottii

The phytochemical investigation of Dimerostemma arnottii (Asteraceae) afforded, in addition to a known eudesmanolide, two unusual eudesmane methyl ester derivatives and a new eudesmanolide. Structural elucidation of the compounds was based on their ID and 2D NMR spectroscopic as well as HR-ESI-MS data. There is a remarkable similarity between the structures of the eudesmanes from D. arnottii and those previously encountered in other Dimerostemma species, which is in agreement with the results of a previous phylogenetic study based on molecular data. The chemotaxonomic relevance of the isolated compounds is briefly discussed.

In vitro Fluoride Release and Tensile Bond Strength of a Polymeric Intra-Buccal Bioadhesive

The intra-buccal polymeric bioadhesive systems that can stay adhered to the oral soft tissues for drug programmed release, with the preventive and/or therapeutic purpose has been employed for large clinical situations. A system based on hydroxypropyl methyl cellulose/Carbopol 934`/magnesium stearate (HPMC/Cp/StMg) was developed having the sodium fluoride as active principle. This kind of system was evaluated according to its resistance to the removal by means of physical test of tensile strength. Swine buccal mucosa extracted immediately after animals` sacrifice was employed as substrate for the physical trials, to obtain 16 test bodies. Artificial saliva with or without mucin was used to involve the substrate/bioadhesive system sets during the trials. Artificial salivas viscosity was determined by means of Brookfield viscometer, showing the artificial saliva with mucin 10.0 cP, and the artificial saliva without mucin 7.5 cP. The tensile strength assays showed the following averages: for the group ""artificial saliva with mucin"" - 12.89 Pa, and for the group ""without mucin"" - 12.35 Pa. Statistical analysis showed no significant difference between the assays for both artificial salivas, and it was possible to conclude that the variable mucin did not interfered with the bioadhesion process for the polymeric devices. The device was able to release fluoride in a safe, efficient and constant way up to 8 hours.

In Vivo Antigenotoxicity of Baccharin, an Important Constituent of Baccharis dracunculifolia DC (Asteraceae)

Baccharin (3-prenyl-4-(dihydrocinnamoyloxy)cinnamic acid) is an important chemical compound isolated from the aerial parts of Baccharis dracunculifolia DC (Asteraceae), a native plant of South America, and the most important plant source of Brazilian green propolis. The present study was designed to investigate the ability of baccharin to modulate the genotoxic effects induced by doxorubicin and methyl methanesulphonate in male Swiss mice using the micronucleus and comet assays, respectively. The different doses of baccharin [0.12, 0.24 and 0.48 mg/kg body-weight (b.w.)] were administered simultaneously to doxorubicin (micronucleus test; 15 mg/kg b.w.) and to methyl methanesulphonate (comet assay; 40 mg/kg b.w.). The results showed a significant decrease in the frequency of micronucleated polychromatic erythrocytes in animals treated with baccharin and doxorubicin compared to animals that received only doxorubicin. This reduction ranged from 39.8% to 50.7% in the micronucleus test. The extent of DNA damage in liver cells was significantly lower in animals treated with different concentrations of baccharin combined with methyl methanesulphonate in comparison with the damage observed for animals treated only with methyl methanesulphonate. These differences resulted in a significant reduction in the extent of DNA damage, which ranged from 47.8% to 60.6%.

Sub-Chronic Exposure to Methylmercury at Low Levels Decreases Butyrylcholinesterase Activity in Rats

In this study, we examined the effects of low levels and sub-chronic exposure to methylmercury (MeHg) on butyrylcholinesterase (BuChE) activity in rats. Moreover, we examined the relationship between BuChE activity and oxidative stress biomarkers [delta-aminolevulinic acid dehydratase (delta-ALA-D) and malondialdehyde levels (MDA)] in the same animals. Rats were separated into three groups (eight animals per group): (Group I) received water by gavage; (Group II) received MeHg (30 mu g/kg/day) by gavage; (Group III) received MeHg (100 mu g/kg/day). The time of exposure was 90 days. BuChE and ALA-D activities were measured in serum and blood, respectively; whereas MDA levels were measured in plasma. We found BuChE and ALA-D activities decreased in groups II and III compared to the control group. Moreover, we found an interesting negative correlation between plasmatic BuChE activity and MDA (r = -0.85; p < 0.01) and a positive correlation between plasmatic BuChE activity and ALA-D activities (r = 0.78; p < 0.01), thus suggesting a possible relationship between oxidative damage promoted by MeHg exposure and the decrease of BuChE activity. In conclusion, long-term exposure to low doses of MeHg decreases plasmatic BuChE activity. Moreover, the decrease in the enzyme is strongly correlated with the oxidative stress promoted by the metal exposure. This preliminary finding highlights a possible mechanism for MeHg to reduce BuChE activity in plasma. Additionally, this enzyme could be an auxiliary biomarker on the evaluation of MeHg exposure.

Effects of methylmercury on male reproductive functions in Wistar rats

In this study we investigated the effects of subacute exposure to methylmercury (MeHg) on male reproductive functions in rats by means of determination of alterations in structural and functional parameters. Adult male Wistar rats received 0, 0.5, 1.0 or 3.0 mg/kg/body weight/day orally, daily MeHg for 14 days. Sperm motility, the relative sperm count and transit time in the caput/corpus epididymis, were all reduced at all doses. The lowest dose increased the number of sperm head abnormalities; daily sperm production was elevated at the intermediate dose; while at the highest dose there was a decrease in serum testosterone levels and a rise in mercury (Hg) content in reproductive organs, liver and kidneys. In conclusion, MeHg exposure produced damages on male reproductive functions which may be attributed, at least in part, to the reduction in serum testosterone levels. These consequences could potentially result in infertility in rats. (C) 2011 Elsevier Inc. All rights reserved.

Mercury speciation in whole blood by gas chromatography coupled to ICP-MS with a fast microwave-assisted sample preparation procedure

A simple and fast method is described for simultaneous determination of methylmercury (MeHg), ethylmercury (Et-Hg) and inorganic mercury (Ino-Hg) in blood samples by using capillary gas chromatography-inductively coupled plasma mass spectrometry (GC-ICP-MS) after derivatization and alkaline digestion. Closed-vessel microwave assisted digestion conditions with tetramethylammonium hydroxide (TMAH) have been optimized. Derivatization by using ethylation and propylation procedures have also been evaluated and compared. The absolute detection limits (using a 1 mu L injection) obtained by GC-ICP-MS with ethylation were 40 fg for MeHg and Ino-Hg, respectively, and with propylation were 50, 20 and 50 fg for MeHg, Et-Hg and Ino-Hg, respectively. Method accuracy is traceable to Standard Reference Material (SRM) 966 Toxic Metals in Bovine Blood from the National Institute of Standards and Technology (NIST). Additional validation is provided based on the comparison of results obtained for mercury speciation in blood samples with the proposed procedure and with a previously reported LC-ICP-MS method. With the new proposed procedure no tedious clean-up steps are required and a considerable improvement of the time of analysis was achieved compared to other methods using GC separation.

The treatment of tardive dyskinesia: A systematic review and meta-analysis

This systematic review aimed to collate randomized controlled trials (RCTs) of various interventions used to treat tardive dyskinesia (TD) and, where appropriate, to combine the data for mete-analysis, Clinical trials were identified by electronic searches, handsearches and contact with principal investigators. Data were extracted independently by two reviewers, for outcomes related to improvement, deterioration, side-effects and drop out rates. Data were pooled using the Mantel-Haenzel Odds Ratio (fixed effect model). For treatments that had significant effects, the number needed to treat (NNT) was calculated. From 296 controlled clinical trials, data were extracted from 47 trials. For most interventions, we could identify no RCT-derived evidence of efficacy. A meta-analysis showed that baclofen, deanol and diazepam were no more effective than a placebo. Single RCTs demonstrated a lack of evidence of any effect for bromocriptine, ceruletide, clonidine, estrogen, gamma linolenic acid, hydergine, lecithin, lithium, progabide, seligiline and tetrahydroisoxazolopyridinol. The meta-analysis found that five interventions were effective: L-dopa, oxypertine, sodium valproate, tiapride and vitamin E; neuroleptic reduction was marginally significant. Data from single RCTs revealed that insulin, alpha methyl dopa and reserpine were more effective than a placebo. There was a significantly increased risk of adverse events associated with baclofen, deanol, L-dopa, oxypertine and reserpine. Metaanalysis of the impact of placebo (n=485) showed that 37.3% of participants showed an improvement. Interpretation of this systematic review requires caution as the individual trials identified tended to have small sample sizes. For many compounds, data from only one trial were available, and where meta-analyses were possible, these were based on a small number of trials. Despite these concerns, the review facilitated the interpretation of the large and diverse range of treatments used for TD. Clinical recommendations for the treatment of TD are made, based on the availability of RCT-derived evidence, the strength of that evidence and the presence of adverse effects. (C) 1999 Elsevier Science B.V. All rights reserved.

cis-3-hydroxy-N-methyl-L-proline: a new amino acid from a southern Australian marine sponge, Dendrilla sp.

A specimen of the sponge Dendrilla sp. collected during commercial trawling operations in the Great Australian Eight, Australia, analyses for a very high natural abundance of the new amino acid cis-3-hydroxy-N-methyl-L-proline (1). The complete stereostructure for (1) was determined by spectroscopic analysis and chemical derivatization.

Sensitive detection of sodium in a flame using parametric four-wave mixing and seeded parametric four-wave mixing

Two-photon resonant parametric four-wave mixing and a newly developed variant called seeded parametric four-wave mixing are used to detect trace quantities of sodium in a flame. Both techniques are simple, requiring only a single laser to generate a signal beam at a different wavelength which propagates collinearly with the pump beam, allowing efficient signal recovery. A comparison of the two techniques reveals that seeded parametric four-wave mixing is more than two orders of magnitude more sensitive than parametric four-wave mixing, with an estimated detection sensitivity of 5 x 10(9) atoms/cm(3). Seeded parametric four-wave mixing is achieved by cascading two parametric four-wave mixing media such that one of the parametric fields generated in the first high-density medium is then used to seed the same four-wave mixing process in a second medium in order to increase the four-wave mixing gain. The behavior of this seeded parametric four-wave mixing is described using semiclassical perturbation theory. A simplified small-signal theory is found to model most of the data satisfactorily. However, an anomalous saturationlike behavior is observed in the large signal regime. The full perturbation treatment, which includes the competition between two different four-wave mixing processes coupled via the signal field, accounts for this apparently anomalous behavior.

Corrosion behaviour of AZ21, AZ501 and AZ91 in sodium chloride

The corrosion behaviour of AZ21, AZ501 and AZ91 was studied in 1 N NaCl at pH 11 by measuring electrochemical polarization curves, electrochemical AC impedance spectroscopy (EIS) and simultaneously measuring the hydrogen evolution rate and the: magnesium dissolution rate. The corrosion rates increased in the following order: AZ501 < AZ21 < AZ91. The: corrosion behaviour was related to alloy microstructure as revealed by optical and electron microscopy. The beta phase was very stable in the test solution and was an effective cathode. The beta phase served two roles, as a barrier and as a galvanic cathode. If the beta phase is present in the alpha matrix as intergranular precipitates with a small volume fraction, then the beta phase mainly serves as a galvanic cathode, and accelerates the corrosion of the alpha matrix. If the beta Fraction is high, then the beta phase may mainly act as an anodic barrier to inhibit the overall corrosion of the alloy. The composition and compositional distribution in the alpha phase is also crucial to the overall corrosion performance of dual phase alloys. Increasing the aluminum concentration in the alpha phase increases the anodic dissolution rate and also increases the cathodic hydrogen evolution rate. Increasing the zinc concentration in the alpha phase may have the opposite effect. (C) 1998 Elsevier Science Ltd. All rights reserved.

mRNA differential display of 2-amino-1-methyl-6-phenylinlidazo[4,5-b]pyridine-induced rat mammary gland tumors

The mRNA differential display technique was used to compare mRNAs between normal mammary gland and turner-derived epithelial cells from female Sprague-Dawley rat mammary gland tumors induced by the heterocyclic amine 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and promoted by a high-fat diet (23.5% corn oil). Two genes, beta-casein and transferrin, were identified as differentially expressed. The expression of these genes was examined across a bank of rat mammary gland tumors derived from animals on a low-fat diet (5% corn oil) or the high-fat diet. Carcinomas had over a 10- and 50-fold lower expression of beta-casein and transferrin, respectively than normal mammary gland. In addition, carcinomas from animals on the high-fat diet showed on average a 5-fold higher expression of beta-casein, and transferrin than carcinomas from animals on the low-fat diet. The results indicate the process of mammary gland tumorigenesis alters the expression of certain genes in the mammary gland, and that the level of dietary fat further modulates the expression of these genes.