878 resultados para 13077-018
Resumo:
Aeromonads are inhabitants of aquatic ecosystems and are described as being involved in intestinal disturbances and other infections. A total of 200 drinking water samples from domestic and public reservoirs and drinking fountains located in Sao Paulo (Brazil), were analyzed for the presence of Aeromonas. Samples were concentrated by membrane filtration and enriched in APW. ADA medium was used for Aeromonas isolation and colonies were confirmed by biochemical characterization. Strains isolated were tested for hemolysin and toxin production. Aeromonas was detected in 12 samples (6.0%). Aeromonas strains (96) were isolated and identified as: A. caviae (41.7%), A. hydrophila (15.7%), A. allosacharophila (10.4%), A. schubertii (1.0%) and Aeromonas spp. (31.2%). The results revealed that 70% of A. caviare, 66.7% of A. hydrophila, 80% of A. allosacharophila and 46.6% of Aeromonas spp. were hemolytic. The assay for checking production of toxins showed that 17.5% of A. caviae, 73.3% of A. hydrophila, 60% of A. allosacharophila, 100% of A. schubertii, and 33.3% of Aeromonas spp. were able to produce toxins. The results demonstrated the pathogenic potential of Aeromonas, indicating that the presence of this emerging pathogen in water systems is a public health concern.
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To evaluate the effect of monensin on the performance of growing cattle under different environmental temperatures, 24 male calves (81.9 +/- 7.7 kg mean weight and 100 days old) were distributed in a 2 x 2 factorial arrangement, contrasting 0 or 85 mg monensin/animal per day at 24.3 or 33.2 degrees C (environmental temperatures). Monensin supplementation increased weight gain (P=0.036), improved feed efficiency (P=0.040), increased ruminal concentrations of volatile fatty acids (VFA; P=0.003) and decreased the molar proportion of butyrate (P=0.034); all effects irrespective of environmental temperatures. A temperature-dependent monensin effect was detected on nitrogen retention (P=0.018) and N retained:N absorbed ratio (P=0.012). Animals fed monensin retained higher N amounts than those of the non-supplemented ones when the environmental temperature was 33.2 degrees C. Environmental temperature and monensin supplementation showed an interaction effect on urine N concentration (P=0.003). Temperature did not affect N excretion in monensin-fed animals, but increased N excretion in the non-supplemented ones. Monensin increased the crude protein (CP) digestibility (P=0.094) for
Resumo:
The present work evaluated the effects of accelerated carbonation on mechanical and physical characteristics of cementitious roofing tiles reinforced with vegetable fibre. The maximum load and toughness of the tiles have increased approximately 25% and 80% respectively as a consequence of the accelerated carbonation. Water absorption and apparent porosity decreased with carbonation while bulk density increased as a clear indication of the densification of the composite. The improvement on the mechanical performance suggests that the fibres retained their tensile strength in the inorganic matrix. Results of specimens extracted from the tested tiles after approximately 480 days in laboratory environment and further aged indicate that soak and dry cycles promoted some leaching of hydration products and more voids and lower density when performed before carbonation. The results indicate the utilization of accelerated carbonation as an effective procedure to mitigate the degradation suffered by the cellulose fibres in the less aggressive medium. (C) 2009 Elsevier Ltd. All rights reserved.
Resumo:
Both gelatin and poly(vinyl alcohol) (PVA) can be cross linked with glutaraldehyde (GLU). In the case of gelatin, the GLU reacts with each e-NH2 functional group of adjacent lysine residues, while for PVA, the GLU reacts with two adjacent hydroxyl groups, forming acetal bridges. Thus it can be considered possible to cross link adjacent macromolecules of gelatin and PVA using GLU. In this context, the aims of this work were the development of biodegradable films based on blends of gelatin and poly(vinyl alcohol) cross linked with GLU, and the characterization of some of their main physical and functional properties. All the films were produced from film-forming solutions (FFS) containing 2 g macromolecules (PVA + gelatin)/100 g FFS, 25 g glycerol/100 g macromolecules, and 4 g GLU (25% solution)/100 g FFS. The FFS were prepared with two concentrations of PVA (20 or 50 g PVA/100 g macromolecules) and two reaction temperatures: 90 or 55 degrees C, applied for 30 min. The films were obtained after drying (30 degrees C/24 h) and conditioning at 25 degrees C and 58% of relative humidity for 7 days, and were then characterized. The results for the color parameters, mechanical properties, phase transitions and infrared spectra showed that some chemical modifications occurred, principally for the gelatin. However, in general, all the characteristics of the films were either typical of films based on blends of these macromolecules without cross linking, or slightly higher. A greater improvement in the properties of this material was probably not observed due to the crystallinity of the PVA, which has a melting point above 90 degrees C. The presence of microcrystals in the polymer chain probably reduced macromolecular mobility, hindering the reaction. Thus more research is necessary to produce biodegradable films with improved properties. (C) 2011 Elsevier Ltd. All rights reserved.
Resumo:
in this paper a study of calcining conditions on the microstructural features of sugar cane waste ash (SCWA) is carried out. For this purpose, some microparticles (< 90 mu m) of sugar cane straw ash and sugar cane bagasse ash of samples calcined at 800 degrees C and 1000 are studied by combining the bright field and the dark field images with the electron diffraction patterns in the transmission electron microscopy (TEM). It is appreciated that the morphology and texture of these microparticles change when silicon or calcium are present. Furthermore, it is observed that iron oxide (magnetite Fe(3)O(4)) is located in the calcium-rich particles. The microstructural information is correlated with the results of a kinetic-diffusive model that allows the computing of the kinetic parameters of the pozzolanic reaction (mainly the reaction rate constant). The results show that the sugar cane wastes ash calcined at 800 and 1000 degrees C have properties indicative of high pozzolanic activity. The X-ray diffraction patterns, the TEM images and the pozzolanic activity tests show the influence of different factors on the activation of these ashes. (c) 2008 Elsevier Ltd. All rights reserved.
Resumo:
The relationships between the four radiant fluxes are analyzed based on a 4 year data archive of hourly and daily global ultraviolet (I(UV)), photosynthetically active-PAR (I(PAR)), near infrared (I(NIR)) and broadband global solar radiation (I(G)) collected at Botucatu, Brazil. These data are used to establish both the fractions of spectral components to global solar radiation and the proposed linear regression models. Verification results indicated that the proposed regression models predict accurately the spectral radiant fluxes at least for the Brazilian environment. Finally, results obtained in this analysis agreed well with most published results in the literature. (c) 2010 Elsevier Ltd. All rights reserved.
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Laurencia marilzae is recorded for the first time from the western Atlantic Ocean; it was found in Laje de Santos Marine State Park, Sao Paulo, southeastern Brazil. The specimens were collected in the rocky subtidal zone from 7 to 15 m depth. The most distinctive characteristic of this species is the presence of corps en cerise in all cells of the thallus, including cortex, medulla, and trichoblasts. The phylogenetic position of the species was inferred by analysis of the chloroplast-encoded rbcL gene sequences from 43 taxa, using two other rhodomelacean taxa and two members of the Ceramiaceae as outgroups. Within the Laurencia assemblage, L. marilzae from Brazil and from the Canary Islands ( type locality) formed a distinctive lineage sister to all other Laurencia species analyzed. Male plants are described for the first time. This study expands the geographical distribution of L. marilzae to the western Atlantic Ocean.
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Objective: To investigate whether submicroscopic copy number variants (CNVs) on the X chromosome can be identified in women with primary ovarian insufficiency (POI), defined as spontaneous secondary amenorrhea before 40 years of age accompanied by follicle-stimulating hormone levels above 40 IU/L on at least two occasions. Design: Analysis of intensity data of single nucleotide polymorphism (SNP) probes generated by genomewide Illumina 370k CNV BeadChips, followed by the validation of identified loci using a custom designed ultra-high-density comparative genomic hybridization array containing 48,325 probes evenly distributed over the X chromosome. Setting: Multicenter genetic cohort study in the Netherlands. Patient(s): 108 Dutch Caucasian women with POI, 97 of whom passed quality control, who had a normal karyogram and absent fragile X premutation, and 235 healthy Dutch Caucasian women as controls. Intervention(s): None. Main Outcome Measure(s): Amount and locus of X chromosomal microdeletions or duplications. Result(s): Intensity differences between SNP probes identify microdeletions and duplications. The initial analysis identified an overrepresentation of deletions in POI patients. Moreover, CNVs in two genes on the Xq21.3 locus (i.e., PCDH11X and TGIF2LX) were statistically significantly associated with the POI phenotype. Mean size of identified CNVs was 262 kb. However, in the validation study the identified putative Xq21.3 deletions samples did not show deviations in intensities in consecutive probes. Conclusion(s): X chromosomal submicroscopic CNVs do not play a major role in Caucasian POI patients. We provide guidelines on how submicroscopic cytogenetic POI research should be conducted. (Fertil Steril (R) 2011;95:1584-8. (C) 2011 by American Society for Reproductive Medicine.)
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Role of reactive oxygen species (ROS)/nitric oxide (NO) balance and renin-angiotensin system in mediating cardiac hypertrophy in hyperthyroidism was evaluated in an in vivo and in vitro experimental model. Male Wistar rats were divided into four groups: control, thyroid hormone, vitamin E (or Trolox, its hydrosoluble analogue), thyroid hormone + vitamin E. Angiotensin II receptor (AT1/AT2) gene expression, immunocontent of AT1/AT2 receptors, angiotensinogen, NADPH oxidase (Nox2), and nitric oxide synthase isoforms, as well as ROS concentration (hydrogen peroxide and superoxide anion) were quantified in myocardium. Thyroid hormone increased ROS and NO metabolites, iNOS, nNOS and eNOS isoforms and it was accompanied by cardiac hypertrophy. AT1/AT2 expression and the immunocontent of angiotensinogen and Nox2 were enhanced by thyroid hormone. Antioxidants reduced ROS levels, Nox2, AT1/AT2, NOS isoforms and cardiac hypertrophy. In conclusion, ROS/NO balance may play a role in the control of thyroid hormone-induced cardiac hypertrophy mediated by renin-angiotensin system. (C) 2011 Elsevier Ireland Ltd. All rights reserved.
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In the present study we evaluated the effect of chronic methionine administration on oxidative stress and biochemical parameters in liver and serum of rats, respectively. We also performed histological analysis in liver. Results showed that hypermethioninemia increased chemiluminescence, carbonyl content and glutathione peroxidase activity, decreased total antioxidant potential, as well as altered catalase activity. Hypermethioninemia increased synthesis and concentration of glycogen, besides histological studies showed morphological alterations and reduction in the glycogen/glycoprotein content in liver. Serum alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and glucose were increased in hypermethioninemic rats. These findings suggest that oxidative damage and histological changes caused by methionine may be related to the hepatic injury observed in hypermethioninemia. (C) 2009 Elsevier Masson SAS. All rights reserved.
Resumo:
Introduction: Toll-like receptors (TLR) comprehend an emerging family of receptors that recognize pathogen-associated molecular patterns and promote the activation of leukocytes. Surgical trauma and ischemia-reperfusion injury are likely to provide exposure to endogenous ligands for TLR in virtually all kidney transplant recipients. Methods: Macroarray (GEArray OHS-018.2 Series-Superarray) analyses of 128 genes involved in TLR signaling pathway were performed in nephrectomy samples of patients with chronic allograft nephropathy (CAN) and acute rejection (AR, vascular and non vascular). The analysis of each membrane was performed by GEArray Expression Analysis Suite 2.0. Results: Macroarray profile identified a gene expression signature that could discriminate CAN and AR. Three genes were significantly expressed between CAN and vascular AR: Pellino 2; IL 8 and UBE2V1. In relation to vascular and non-vascular AR, there were only two genes with statistical significance: IL-6 and IRAK-3. Conclusion: Vascular and non-vascular AR and CAN showed different expression of a few genes in TLR pathway. The analysis of nephrectomy showed that activation of TLR pathway is present in AR and CAN. (C) 2008 Elsevier B.V. All rights reserved.
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The objective of the present work was to evaluate the relevance of the 2-methylcitric acid cycle (2MCC) to the catabolism of propionate in Burkholderia sacchari. Two B. sacchari mutants unable to grow on propionate were obtained: one disrupted in acnM, and the other in acnM and prpC deleted. An operative 2MCC significantly reduces the bacterial ability to incorporate 3-hydroxyvalerate (3HV) into a biodegradable copolyester accumulated from carbohydrates plus propionate. The efficiency of the mutants in converting propionate to 3HV units (Y(3HV/prp)) increased from 0.09 g.g(-1) to 0.81-0.96 g.g(-1), indicating that acnM and prpC are both essential for growth on propionate. None of the mutations resulted in achievement of the maximum theoretical Y(3HV/prp) (1.35 g.g(-1)). When increasing concentrations of propionate were supplied, decreasing values of Y(3HV/prp) were observed. The results obtained corroborate the hypothesis of the presence of other propionate catabolic pathways in B. sacchari. The 2MCC would be the more operative pathway, but a second pathway, which remains to be elucidated, would assume more importance under propionate concentrations of 1 g.L(-1) or higher. The efficiency in converting propionate to 3HV units can be improved by decreasing the propionate concentrations, owing to the role of the 2MCC.
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White adipose tissue (WAT) is the source of pro- and anti-inflammatory cytokines and recently, it has been recognized as an important source of interleukin 10 (IL-10). Acute physical exercise is known to induce an anti-inflammatory cytokine profile, however, the effect of chronic physical exercise on the production of IL-10 by WAT has never been examined. We assessed IL-10 and TNF-alpha concentration in WAT of rats engaged in endurance training. Animals were randomly assigned to either a sedentary control group (S, n = 7) or an endurance trained group (T, n = 8). Trained rats ran on a treadmill 5 days/wk for 8 wk (55-65% VO(2max). Detection of IL-10 and TNF-alpha protein and mRNA expression, as well as the gene expression of PPAR-gamma, and immunocytochemistry to detect mononuclear phagocytes were carried out. A reduction in absolute retroperitoneal adipose tissue (RPAT) weight in T (44%; p < 0.01), when compared with S was observed. IL-10 concentration was increased (1.5-fold, p < 0.05), to a higher extent than that of TNF-alpha (66%. p < 0.05) in the mesenteric adipose tissue (MEAT) of the trained group, while no change related to training was observed in RPAT. In MEAT, IL-10/TNF-alpha ratio was increased in T, when compared with S (30%; p < 0.05). PPAR-gamma gene expression was increased in T (1.1-fold; p < 0.01), when compared with S in the same adipose depot. No monocyte infiltration was found. In conclusion, exercise training induced increased IL-10 expression in the mesenteric depot, resulting in a modified IL-10/TNF-alpha ratio. We also conclude that WAT presents a depot-specific response to endurance training regarding the studied aspects. (C) 2008 Elsevier Ltd. All rights reserved.
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Diabetic individuals are more susceptible to infections and this seems to be related to impaired phagocyte function. Alveolar macrophages (AMs) are the first barrier to prevent respiratory infections Leukotrienes (LTs) increase AM phagocytic activity via Fc gamma R. In this study, we compared AMs from diabetic and nondiabetic rats for phagocytosis via Fc gamma R and the roles of LTs and insulin Diabetes was induced in male Wistar rats by alloxan (42 mg/kg, i.v); macrophages were obtained by bronchoalveolar lavage and IgG-opsonised sheep red blood cells (IgG-SRBC) were used as targets. LTs were added to the AMs 5 min before the addition of IgG-SRBC. AMs were treated with a LT synthesis inhibitor (zileuton, 10 mu M), or antagonists of the LTB(4) receptor (CP105 696, 10 mu M) cys-LT receptor (MK571, 10 mu M), 30 or 20 min before the addition of IgG-SRBC, respectively. We found that the phagocytosis of IgG-SRBC by AMs from diabetic rats is impaired compared with non-diabetic rats. Treatment with the LT inhibitor/antagonists significantly reduced AM phagocytosis in non-diabetic but not diabetic rats. During the phagocytosis of IgG-SRBC LTB(4) and LTC(4) were produced by AMs from both groups. The addition of exogenous LTB(4) or LTD(4) potentiated phagocytosis similarly in both groups Phagocytosis was followed by the phosphorylation of PKC-delta. ERK and Akt This was reduced by zileuton treatment in AMs from non-diabetic but not diabetic rats The addition of insulin to AMs further increased the phagocytosis by increasing PKC-delta phosphorylation These results suggest that the impaired phagocytosis found in AMs from diabetic rats is related to a deficient coupling of LTs to the Fc gamma R signaling cascade and that insulin has a key role in this coupling An essential role for insulin in Innate immunity is suggested (C) 2010 Elsevier Ltd. All rights reserved.
Resumo:
In this paper, we formulate a flexible density function from the selection mechanism viewpoint (see, for example, Bayarri and DeGroot (1992) and Arellano-Valle et al. (2006)) which possesses nice biological and physical interpretations. The new density function contains as special cases many models that have been proposed recently in the literature. In constructing this model, we assume that the number of competing causes of the event of interest has a general discrete distribution characterized by its probability generating function. This function has an important role in the selection procedure as well as in computing the conditional personal cure rate. Finally, we illustrate how various models can be deduced as special cases of the proposed model. (C) 2011 Elsevier B.V. All rights reserved.