Characteristics of the histamine release from hamster cheek pouch mast cells stimulated by lectins from Brazilian beans and concanavalin A

We have characterized the histamine releasing effects of lectins extracted from Brazilian beans, in comparison to concanavalin A, in hamster cheek pouch cell suspensions containing mast cells. The lectins from Dioclea virgata, Canavalia brasiliensis, and Dioclea rostrata induce histamine release in a similar manner to concanavalin A, but appear to differ in potency and efficacy. The effects depended on the temperature, pH, and metabolic energy, demonstrating the non-cytotoxic nature of the histamine release. It is suggested that the lectins studied act by the same mechanism as concanavalin A (interacting with sugars in the antibodies bound to the mast cells), since high concentrations of glucose inhibit the histamine release. The lectins at high concentrations quench the histamine release. This suppression is reversed by increasing calcium concentration, suggesting that the lectins bind to the calcium that is essential for the secretion, thereby confirming and extending our previous data using the lectin from Dioclea virgata in rat peritoneal mast cells.

Dissipative three-wave structures in stimulated backscattering. I. A subluminous solitary attractor

We present a solitary solution of the three-wave nonlinear partial differential equation (PDE) model - governing resonant space-time stimulated Brillouin or Raman backscattering - in the presence of a cw pump and dissipative material and Stokes waves. The study is motivated by pulse formation in optical fiber experiments. As a result of the instability any initial bounded Stokes signal is amplified and evolves to a subluminous backscattered Stokes pulse whose shape and velocity are uniquely determined by the damping coefficients and the cw-pump level. This asymptotically stable solitary three-wave structure is an attractor for any initial conditions in a compact support, in contrast to the known superluminous dissipative soliton solution which calls for an unbounded support. The linear asymptotic theory based on the Kolmogorov-Petrovskii-Piskunov assertion allows us to determine analytically the wave-front slope and the subluminous velocity, which are in remarkable agreement with the numerical computation of the nonlinear PDE model when the dynamics attains the asymptotic steady regime. © 1997 The American Physical Society.

Field-free and field-stimulated electron emission from solids

Electron irradiation of solids produces a backemission of secondary electrons (energies between 0 and 50 eV) and reflected primaries (energies between 50 eV and that of the incident beam). For insulators, it is shown that an externally applied positive electric field penetrating into the solid material, energizes electrons generated by the primary irradiation and enables them to travel back to the surface of incidence and be emitted (stimulated secondary emission).

Absorption and translocation of 2,4-D in plants of Memora peregrina

The objective of this work was to evaluate absorption and translocation of the herbicide 2,4-D in plants of Memora peregrina. The herbicide 2,4-D was used alone with the formulation DMA 806 BR and associated with the herbicide picloram in the commercial product Padron. Levels of radioactivity on the treated leaves were determined in sample obtained after washing them with methanol and chloroform at different times after the application of the radiolabelled formulation (1, 2, 4, 8, 24, and 48 h). Translocation was evaluated by cutting plants between stem and root. The parts obtained were: root, stem, leaf treated, leaves above the leaf treated, leaves below the leaf treated, and leaf opposite of the leaf treated. These parts were weighted, dried, ground, burnt, and radioactivity in the samples was determined. The results suggest that the translocation of the radioactive herbicide 2,4-D was insignificant in plants of M. peregrina in the two treatments evaluated. Absorption of 14C 2,4-D in the treatment with DMA 806 BR and the mixture of DMA 806 BR plus Padron had the same behavior. These observations explain the inefficient control obtained with this herbicide in plant species under study.

Age related obesity-induced shortening of GLUT4 mRNA poly(A) tail length in rat gastrocnemius skeletal muscle

Obese insulin resistant animals and humans have shown reduced GLUT4 gene expression. Yet, in skeletal muscle, discrepancy between mRNA and protein regulation has been frequently observed, suggesting a post-transcriptional modulation. We investigated the GLUT4 expression in adipose tissue and muscle of obese 12-month-old (12-mo) rats, comparing with lean 2-month-old (2-mo) animals. Obesity was accompanied by insulin resistance, and 65% reduction (P < 0.01) in GLUT4 mRNA and protein in adipose tissue. However, in muscle, despite increased (P < 0.05) mRNA content, GLUT4 protein was unchanged. RNase H and poly(A) test assays showed a reduction (P < 0.01) of ∼80 adenines in the GLUT4 mRNA poly(A) tail of muscle from 12-mo rats, recognizing that the poly(A) tail length correlates with translation efficiency. Concluding, age related obesity of 12-mo rats involves suppression of GLUT4 expression in adipose tissue; however, in muscle, GLUT4 mRNA content increases, but with a shorter poly(A) tail, thus unchanging the protein content. © 2007 Elsevier B.V. All rights reserved.

Human eosinophil adhesion and degranulation stimulated with eotaxin and RANTES in vitro: Lack of interaction with nitric oxide

Background: Airway eosinophilia is considered a central event in the pathogenesis of asthma. The toxic components of eosinophils are thought to be important in inducing bronchial mucosal injury and dysfunction. Previous studies have suggested an interaction between nitric oxide (NO) and chemokines in modulating eosinophil functions, but this is still conflicting. In the present study, we have carried out functional assays (adhesion and degranulation) and flow cytometry analysis of adhesion molecules (VLA-4 and Mac-1 expression) to evaluate the interactions between NO and CC-chemokines (eotaxin and RANTES) in human eosinophils. Methods: Eosinophils were purified using a percoll gradient followed byimmunomagnetic cell separator. Cell adhesion and degranulation were evaluated by measuring eosinophil peroxidase (EPO) activity, whereas expression of Mac-1 and VLA-4 was detected using flow cytometry. Results: At 4 h incubation, both eotaxin (100 ng/ml) and RANTES (1000 ng/ml) increased by 133% and 131% eosinophil adhesion, respectively. L-NAME alone (but not D-NAME) also increased the eosinophil adhesion, but the co-incubation of L-NAME with eotaxin or RANTES did not further affect the increased adhesion seen with chemokines alone. In addition, L-NAME alone (but not D-NAME) caused a significant cell degranulation, but it did not affect the CC-chemokine-induced cell degranulation. Incubation of eosinophils with eotaxin or RANTES, in absence or presence of L-NAME, did not affect the expression of VLA-4 and Mac-1 on eosinophil surface. Eotaxin and RANTES (100 ng/ml each) also failed to elevate the cyclic GMP levels above baseline in human eosinophils. Conclusion: Eotaxin and RANTES increase the eosinophil adhesion to fibronectin-coated plates and promote cell degranulation by NO-independent mechanisms. The failure of CC-chemokines to affect VLA-4 and Mac-1 expression suggests that changes in integrin function (avidity or affinity) are rather involved in the enhanced adhesion. © 2008 Lintomen et al; licensee BioMed Central Ltd.

Regulation of visfatin by microbial and biomechanical signals in PDL cells

Objectives: This in vitro study was established to examine whether visfatin thought to be a link between periodontitis and obesity is produced by periodontal ligament (PDL) cells and, if so, whether its synthesis is modulated by microbial and/or biomechanical signals. Materials and methods: PDL cells seeded on BioFlex® plates were exposed to the oral pathogen Fusobacterium nucleatum ATCC 25586 and/or subjected to biomechanical strain for up to 3 days. Gene expression of visfatin and toll-like receptors (TLR) 2 and 4 was analyzed by RT-PCR, visfatin protein synthesis by ELISA and immunocytochemistry, and NFκB nuclear translocation by immunofluorescence. Results: F. nucleatum upregulated the visfatin expression in a dose- and time-dependent fashion. Preincubation with neutralizing antibodies against TLR2 and TLR4 caused a significant inhibition of the F. nucleatum-upregulated visfatin expression at 1 day. F. nucleatum stimulated the NFκB nuclear translocation. Biomechanical loading reduced the stimulatory effects of F. nucleatum on visfatin expression at 1 and 3 days and also abrogated the F. nucleatum-induced NFκB nuclear translocation at 60 min. Biomechanical loading inhibited significantly the expression of TLR2 and TLR4 at 3 days. The regulatory effects of F. nucleatum and/or biomechanical loading on visfatin expression were also observed at protein level. Conclusions: PDL cells produce visfatin, and this production is enhanced by F. nucleatum. Biomechanical loading seems to be protective against the effects of F. nucleatum on visfatin expression. Clinical relevance: Visfatin produced by periodontal tissues could play a major role in the pathogenesis of periodontitis and the interactions with obesity and other systemic diseases. © 2013 Springer-Verlag Berlin Heidelberg.

CCL3 and CXCL12 production in vitro by dental pulp fibroblasts from permanent and deciduous teeth stimulated by Porphyromonas gingivalis LPS

Objective: The aim of this study was to compare the production of the chemokines CCL3 and CXCL12 by cultured dental pulp fibroblasts from permanent (PDPF) and deciduous (DDPF) teeth under stimulation by Porphyromonas gingivalis LPS (PgLPS). Material and Methods: Primary culture of fibroblasts from permanent (n=3) and deciduous (n=2) teeth were established using an explant technique. After the fourth passage, fibroblasts were stimulated by increasing concentrations of PgLPS (0 - 10 pg/mL) at 1, 6 and 24 h. The cells were tested for viability through MTT assay, and production of the chemokines CCL3 and CXCL12 was determined through ELISA. Comparisons among samples were performed using One-way ANOVA for MTT assay and Two-way ANOVA for ELISA results. Results: Cell viability was not affected by the antigen after 24 h of stimulation. PgLPS induced the production of CCL3 by dental pulp fibroblasts at similar levels for both permanent and deciduous pulp fibroblasts. Production of CXCL12, however, was significantly higher for PDPF than DDPF at 1 and 6 h. PgLPS, in turn, downregulated the production of CXCL12 by PDPF but not by DDPF. Conclusion: These data suggest that dental pulp fibroblasts from permanent and deciduous teeth may present a differential behavior under PgLPS stimulation.

Laser stimulated light reflection for TeO2-WO 3-Bi2O3 thin films with incorporated Si nanoparticles

A novel method of preparation of the Si nanoparticles (NPs) incorporated in tellurite TeO2-WO3-Bi2O3 (TWB) thin films is proposed. This mew method applies RF magnetron sputtering technique at room temperature. The incorporation of Si NP was confirmed by transmission electron microscopy (TEM); isolated Si NPs with diameters of around 6 nm are observed. Energy dispersive X-ray spectroscopy (EDS) was performed during TEM analysis in order to confirm the presence of Si NP and also the other elements of the thin film. The thin films are explored with respect to the photoinduced changes of the reflectivity within the 400-65 nm spectra range using a 10 ns pulsed Nd:YAG with power densities varying up to 400 MW/cm2 and beam diameter within the 3-5 mm range. The observed processes are analyzed within a framework of trapping level conceptions for the Si NP. The possible application of the discovered materials as optical sensitive sensors is proposed. © 2013 Elsevier B.V.

Cysteine proteinase inhibitors regulate human and mouse osteoclastogenesis by interfering with RANK signaling

The cysteine proteinase inhibitor cystatin C inhibited RANKL-stimulated osteoclast formation in mouse bone marrow macrophage cultures, an effect associated with decreased mRNA expression of Acp5, Calcr, Ctsk, Mmp9, Itgb3, and Atp6i, without effect on proliferation or apoptosis. The effects were concentration dependent with half-maximal inhibition at 0.3 μM. Cystatin C also inhibited osteoclast formation when RANKL-stimulated osteoclasts were cultured on bone, leading to decreased formation of resorption pits. RANKL-stimulated cells retained characteristics of phagocytotic macrophages when cotreated with cystatin C. Three other cysteine proteinase inhibitors, cystatin D, Z-RLVG-CHN2 (IC50 0.1 μM), and E-64 (IC 50 3 μM), also inhibited osteoclast formation in RANKL-stimulated macrophages. In addition, cystatin C, Z-RLVG-CHN2, and E-64 inhibited osteoclastic differentiation of RANKL-stimulated CD14+ human monocytes. The effect by cystatin C on differentiation of bone marrow macrophages was exerted at an early stage after RANKL stimulation and was associated with early (4 h) inhibition of c-Fos expression and decreased protein and nuclear translocation of c-Fos. Subsequently, p52, p65, IκBα, and Nfatc1 mRNA were decreased. Cystatin C was internalized in osteoclast progenitors, a process requiring RANKL stimulation. These data show that cystatin C inhibits osteoclast differentiation and formation by interfering intracellularly with signaling pathways downstream RANK. © FASEB.

Comparison of Brazilian plants used to treat gastritis on the oxidative burst of helicobacter pylori -stimulated neutrophil

Ten Brazilian medicinal plants used to treat gastritis and ulcers were carefully selected on the basis of ethnopharmacological importance and antiulcerogenic activity previously described. The antioxidant activity of the methanolic extracts was determined in analysis conditions that simulate a real biological activity on inhibition of the oxidative burst induced in neutrophils using Helicobacter pylori as activator, by a luminol-amplified chemiluminescence assay. The extracts, at low concentration (5 g/mL), exhibited a large variation in inhibitory effects of H. pylori-induced oxidative burst ranging from 48% inhibition to inactive, but all extracts, excluding Byrsonima intermedia, had inhibitory activity over 80% at the concentration of 100 g/mL. The total suppressive antioxidant capacity measured as the effective concentration, which represents the extract concentration producing 50% inhibition of the chemiluminescence induced by H. pylori, varies from 27.2 to 56.8 g/mL and was in the following order: Qualea parviflora > Qualea multiflora > Alchornea triplinervia > Qualea grandiflora > Anacardium humile > Davilla elliptica > Mouriri pusa > Byrsonima basiloba > Alchornea glandulosa > Byrsonima intermedia. The main groups of compounds in tested extracts are presented. Differences in the phytochemical profile, quantitatively and qualitatively, of these plants can explain and justify their protective effect on the gastric mucosa caused by the neutrophil-generated ROS that occurs when H. pylori displays its evasion mechanisms. © 2013 Cibele Bonacorsi et al.

Propolis and its constituent caffeic acid suppress LPS-stimulated pro-inflammatory response by blocking NF-κB and MAPK activation in macrophages

Ethnopharmacological relevance Propolis is a bee product with numerous biological and pharmacological properties, such as immunomodulatory and anti-inflammatory activities. It has been used in folk medicine as a healthy drink and in food to improve health and prevent inflammatory diseases. However, little is known about its mechanism of action. Thus, the goal of this study was to verify the antioxidant activity and to explore the anti-inflammatory properties of propolis by addressing its intracellular mechanism of action. Caffeic acid was investigated as a possible compound responsible for propolis action. Materials and methods The antioxidant properties of propolis and caffeic acid were evaluated by using the 2,2-Diphenyl-1-picrylhydrazyl free radical (DPPH) scavenging method. To analyze the anti-inflammatory activity, Raw 264.7 macrophages were treated with different concentrations of propolis or caffeic acid, and nitric oxide (NO) production, a strong pro-inflammatory mediator, was evaluated by the Griess reaction. The concentrations of propolis and caffeic acid that inhibited NO production were evaluated on intracellular signaling pathways triggered during inflammation, namely p38 mitogen-activated protein kinase (MAPK), c-jun NH2-terminal kinase (JNK1/2), the transcription nuclear factor (NF)-κB and extracellular signal-regulated kinase (ERK1/2), through Western blot using specific antibodies. A possible effect of propolis on the cytotoxicity of hepatocytes was also evaluated, since this product can be used in human diets. Results Caffeic acid showed a higher antioxidant activity than propolis extract. Propolis and caffeic acid inhibited NO production in macrophages, at concentrations without cytotoxicity. Furthermore, both propolis and caffeic acid suppressed LPS-induced signaling pathways, namely p38 MAPK, JNK1/2 and NF-κB. ERK1/2 was not affected by propolis extract and caffeic acid. In addition, propolis and caffeic acid did not induce hepatotoxicity at concentrations with strong anti-inflammatory potential. Conclusions Propolis exerted an antioxidant and anti-inflammatory action and caffeic acid may be involved in its inhibitory effects on NO production and intracellular signaling cascades, suggesting its use as a natural source of safe anti-inflammatory drugs. © 2013 Elsevier B.V.

Efeitos do glyphosate sobre o crescimento e absorção de fósforo pela soja

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeito do treinamento aeróbio e do treinamento anaeróbio na expressão de citocinas e de transportador de glicose GLUT4 no tecido muscular esquelético de ratos obesos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito da exposição à fumaça de cigarro sobre a expressão de GLUT4 em ratas prenhes e lactantes e sua prole

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)