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P-glycoprotein (P-gp) is an ABC transporter exhibiting high pharmacotoxicological relevance by extruding a wide range of cytotoxic compounds out of the cells. Previously, we demonstrated that the phytoestrogen genistein (GNT) modulates P-gp expression in hepatocellular carcinoma in vitro. Although several beneficial effects (e.g., antioxidant, antimutagenic, anticancer) have been attributed to GNT, the molecular mechanisms have not been totally elucidated. In the present work, we evaluated the effect of GNT on P-gp expression in rat liver, kidney and ileum. We found that GNT (5 mg/kg daily s.c. 3 days) increased hepatic P-gp expression and also Mdr1a (one of the genes encoding P-gp) mRNA levels. Renal and intestinal P-gp remained unchanged after GNT treatment. Hepatic P-gp activity measured with rhodamine-123 and digoxin, both well-known P-gp substrates, was also increased. In vitro experiments using hepatocyte primary cell culture demonstrated that inhibition of ER-α with ICI182/780 did not prevent Mdr1a mRNA up-regulation by GNT (10 µM). In contrast, Mdr1a induction was suppressed after pregnane X receptor (PXR) inhibition by sulforaphane and knockdown of this nuclear receptor. These findings were confirmed in vivo by using the PXR antagonist ketoconazole. In conclusion, we demonstrated the induction of hepatic P-gp expression and activity by GNT in vivo, with PXR being a likely mediator. This suggests that GNT, at concentrations observed in plasma of individuals consuming the phytoestrogen in the diet or through supplements, could affect the clearance of relevant P-gp substrates of therapeutic use as well as toxicity of environmental and food toxicants. [ABSTRACT FROM AUTHOR]

This article describes the development of fire resistant composite materials based on phenolic resin and carbon fibers. Two types of composites were developed, with neat phenolic resin and with phenolic resin/modified bentonite. Composite materials were processed from prepregs by compression molding and were characterized by density, fiber content, cone calorimeter test, scanning electron microscope, and mechanical properties before and after the exposure to fire. In both cases, high fiber content materials were developed, about 75% by volume. The addition of clay improved some fire properties such as the peak of the heat release rate and the residual mass of the burned samples. Also, the bentonite-modified composite required higher time to develop the maximum of the heat release rate in the material; therefore, the addition of modified nanoclays improved the fire properties of the developed composites. Regarding to mechanical behavior the modified composites presented low modulus and flexural stiffness than the unmodified materials, and presented a higher decreased in the properties after fire, which could be related with the different fiber content in both composites. [ABSTRACT FROM AUTHOR]

Quercetin, rutin, naringin, hesperidin and chrysin were tested as substrates for cloroperoxidase to produce reactive quinones to graft onto chitosan. Quercetin and rutin quinones were successfully chemically attached to low molecular weight chitosan. The quercetin-modified chitosan showed an enhancement of plastic, antioxidant and antimicrobial properties as well as of thermal degradability. Finally, chitosan-quercetin films visibly decreased enzymatic oxidation when applied to Opuntia ficus indica cladodes. [ABSTRACT FROM AUTHOR]

Aim: The feasibility of administering native glucagon-like peptide 1 (GLP-1) as GLP-1 Technosphere® Inhalation Powder for diabetes therapy has been demonstrated in a rat model. Methods: GLP-1 Technosphere Inhalation Powders containing 5, 10 and 15% GLP-1 were prepared and administered to healthy female Sprague–Dawley rats and to male Zucker diabetic obese rats. Rats received a single dose of GLP-1 Technosphere Powder by pulmonary insufflation. GLP-1 pharmacokinetic and pharmacodynamic responses were measured. Results: Maximum circulating GLP-1 concentrations were achieved at ∼10 min after dosing with detectable levels at 40 min. In a food consumption study, Sprague–Dawley rats receiving GLP-1 Technosphere Powder once-daily consumed less food than control rats for up to 24 h after dosing. Cumulative food consumption was decreased approximately 10% after 78 h. In an intraperitoneal glucose tolerance test, Zucker diabetic fatty rats receiving 2 mg GLP-1 Technosphere Powder (0.3 mg GLP-1) by pulmonary insufflation exhibited lower glucose concentrations and higher insulin concentrations than control rats. Pancreatic evaluations showed no differences in apoptotic index or cell proliferation of β-cells. In addition, a dose-related increase in insulin expression within the pancreas was observed. Conclusions: These data demonstrate the feasibility of administering native GLP-1 as GLP-1 Technosphere Inhalation Powder for diabetes therapy. [ABSTRACT FROM AUTHOR]

An update of the work carried out by our group in the field of voltammetric sensors is presented. A simplified array formed by carbon paste electrodes (CPE) modified with three rare-earth bisphthalocyanines and three perylenes has been constructed. Chemical modifiers have been selected because of their complementary redox activity. Using square wave voltammetry, the array has provided a rich variety of voltammetric responses towards acids, bases, ionic solutions and antioxidants such as tannic acid or citric acid. This cross-selectivity is due to diffusion of ions inside the electrode to the sensitivity of the materials to protons and to the presence of oxidizing or reducing agents (i.e. perchlorate or tannins). The array of electrodes has been used to analyse white wines elaborated with different varieties of grapes. Principal component analysis conducted using Kernel functions demonstrated that the capability of discriminating white wines is similar to that observed in red wines. Loading plots confirm that the information provided by sensors modified with phthalocyanines and perylenes is highly complementary. [ABSTRACT FROM AUTHOR]

Ditaxis heterantha, a plant of the Euphorbiaceae family, is growing wild in the semiarid regions of Mexico. The seed endosperm contains yellow pigments (carotenoids). By high-pressure liquid chromatography the total pigment (TP) was separated into seven fractions: two of them, heterathin (F4) and ditaxin (F5), characterized as apocarotenoids, represent 80% of TP. Both molecules have double bonds, which seem to be the target for degradation and aroma formation. In this work, TP, F4, and F5 were supplied to nine cultures able to degrade lutein. From these strains, only one (identified as Saccharomyces cerevisiae) was able to produce aromas from either TP or F4. Using TP as substrate, the produced aromas were 4-oxo-isophorone (1), isophorone (2), cinnamic aldehyde (6), 3-hydroxy-β-cyclocitral (7), safranal (8), geranyl (9), 3-oxo-α-ionone (10), 3-oxo-α-ionol (11), 3-oxo-7,8-dihydro-α-ionone (12), and eugenol (13). Of these aromas, only seven were produced from F4: (1), (2), (7), (8), (10), (11), and (12). In both cases, safranal was the main degradation product (30%). The enzymatic activity responsible for this effect was found in the cytosolic fraction and detected only when S. cerevisiae was grown in the presence of TP or F4. [ABSTRACT FROM AUTHOR]

Introduction: The exposure to high altitude (H) produces several physiologic alterations which may induce changes in the pharmacokinetics of drugs. This hypothesis has been confirmed in previous studies which suggest that drugs which are highly bound to plasma proteins are most likely to exhibit altered pharmacokinetics. Objectives: To further elucidate the influence of H on pharmacokinetics, prednisolone was selected, since it is highly bound to plasma proteins, renally excreted and poorly bound to red blood cells. Subjects, materials and methods: Prednisolone (80 mg) was given orally to three groups of young healthy volunteers. One group was residing at sea level (L): the same volunteers were studied again after 15 hours of exposure to high altitude (3600 m, HA group), and volunteers living at H for at least six months (group HC). Results: There were no statistically significant differences in the pharmacokinetic parameters calculated from plasma data in the three situations studied. When calculated from whole blood data, how ever, AUC and C max were in creased and both volume of distribution and clearance diminished after exposure to H, either acute or chronically. Binding to proteins increased significantly after H exposure from 57% in group L to 75% and 94% in group H and HC, respectively. Binding to erythrocytes also increased with H exposure from 43.7% in group L to 50.6% and 61.6% in group HA and HC, respectively. The prednisolone/prednisone ratio in urine was 11.1 in group L, 7.3 in group HA and 45.6 in group HC. Conclusion: Since prednisone has very little intrinsic glucocorticoid activity and has to be converted to prednisolone for therapeutic effect, the alteration of the prednisolone/prednisone ratio, as a result of high altitude exposure could be clinically relevant. Additional experiments are desirable to further evaluate this observation. [ABSTRACT FROM AUTHOR]

This work represents the first attempt to develop a sensory system, specifically designed for the characterization of wines, which combines three sensory modalities: an array of gas sensors, an array of electrochemical liquid sensors, and an optical system to measure color by means of CIElab coordinates. This new analytical tool, that has been called "electronic panel," includes not only sensors, but also hardware (injection system and electronics) and the software necessary for fusing information from the three modules. Each of the three sensory modalities (volatiles, liquids, and color) has been designed, tested, and optimized separately. The discrimination capabilities of the system have been evaluated on a database consisting of six red Spanish wines prepared using the same variety of grape (tempranillo) but differing in their geographic origins and aging stages. Sensor signals from each module have been combined and analyzed using pattern recognition techniques. The results of this work show that the discrimination capabilities of the system are significantly improved when signals from each module are combined to form a multimodal feature vector. [ABSTRACT FROM PUBLISHER]

The article presents a study that aims to examine the toxicity of cadmium and zinc to white shrimp juveniles as well as the interaction of these metals. For the subjects of the study, juvenile Penaeus setiferus were captured during the winter months at Términos Lagoon, Campeche, Mexico. Tap water was dechlorinated and mixed with full-strength filtered sea water to obtain the desired salinity. Results of the study reflect the complexity of the metals' interaction. Furthermore, the co-exposure to cadmium and zinc had an effect on juvenile P. setiferus that cannot be explained by simple addition of single metal effects while, the toxicity was related to the ratio of the metals in the mixtures.

The article presents a study on the concentration and distribution of organochlorine compounds in oysters and sediments from Coastal Lagoons of the Gulf of Mexico. It states that sediments and vivalve mollusks (Crassostrea virginica) samples were obtained from the coastal lagoons Carmen, and Machona in Tobasco, and Alvarado in Veracruz. The result showed that pesticides concentrations found in the study exceeds the pesticides described by other auhors.