960 resultados para 5 beta
Resumo:
beta-Carotene (BC) is one of the natural pigments that is most commonly added to food; however, the utilization of BC is limited due to its instability. Microencapsulation techniques are commonly used because they can protect the microencapsulated material from oxidization. Nevertheless, the properties of the encapsulated compounds must be studied. We compared the antigenotoxic potential of pure and microencapsulated beta-carotene (mBC) in Wistar rats. Two doses of BC or mBC (2.5 or 5.0 mg/kg) were administered by gavage over a period of 14 days. The final gavage was followed by an injection of doxorubicin (DXR). After 24 h the animals were euthanized. The micronucleus test results showed that when both mBC and DXR were given, only the higher dose was antigenotoxic. The results of the comet assay show that when given in association with DXR, mBC had protective effects in the liver. The differences between the results obtained with BC and mBC suggest that possibly the carotenoid biodisponibility was modified by the process of microencapsulation. In conclusion, mBC does not lose its protective properties, but higher doses must be used to observe antigenotoxic effects. This is the first time that the genotoxicity and antigenotoxicity of a microencapsulated compound was evaluated in vivo. (C) 2012 Elsevier Ltd. All rights reserved.
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Agroindustrial residues are materials often rich in cellulose and hemicellulose. The use of these substrates for the microbial production of enzymes of industrial interest is mainly due to their high availability associated with their low cost. In this work, corncob (CCs) particles decomposed to soluble compounds (liquor) were incorporated in the microbial growth medium through autohydrolysis, as a strategy to increase and undervalue xylanase and beta-xylosidase production by Aspergillus terricola and Aspergillus ochraceus. The CCs autohydrolysis liquor produced at 200 A degrees C for 5, 15, 30 or 50 min was used as the sole carbon source or associated with untreated CC. The best condition for enzyme synthesis was observed with CCs submitted to 30 min of autohydrolysis. The enzymatic production with untreated CCs plus CC liquor was higher than with birchwood xylan for both microorganisms. A. terricola produced 750 total U of xylanase (144 h cultivation) and 30 total U of beta-xylosidase (96-168 h) with 0.75% untreated CCs and 6% CCs liquor, against 650 total U of xylanase and 2 total U of beta-xylosidase in xylan; A. ochraceus produced 605 total U of xylanase and 56 total U of beta-xylosidase (168 h cultivation) with 1% untreated CCs and 10% CCs liquor against 400 total U of xylanase and 38 total U of beta-xylosidase in xylan. These results indicate that the treatment of agroindustrial wastes through autohydrolysis can be a viable strategy in the production of high levels of xylanolytic enzymes.
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The study of proportions is a common topic in many fields of study. The standard beta distribution or the inflated beta distribution may be a reasonable choice to fit a proportion in most situations. However, they do not fit well variables that do not assume values in the open interval (0, c), 0 < c < 1. For these variables, the authors introduce the truncated inflated beta distribution (TBEINF). This proposed distribution is a mixture of the beta distribution bounded in the open interval (c, 1) and the trinomial distribution. The authors present the moments of the distribution, its scoring vector, and Fisher information matrix, and discuss estimation of its parameters. The properties of the suggested estimators are studied using Monte Carlo simulation. In addition, the authors present an application of the TBEINF distribution for unemployment insurance data.
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Skeletal muscles from old rats fail to completely regenerate following injury. This study investigated whether pharmacological stimulation of beta 2-adrenoceptors in aged muscles following injury could improve their regenerative capacity, focusing on myofiber size recovery. Young and aged rats were treated with a subcutaneous injection of beta 2-adrenergic agonist formoterol (2 mu g/kg/d) up to 10 and 21 days after soleus muscle injury. Formoterol-treated muscles from old rats evaluated at 10 and 21 days postinjury showed reduced inflammation and connective tissue but a similar number of regenerating myofibers of greater caliber when compared with their injured controls. Formoterol minimized the decrease in tetanic force and increased protein synthesis and mammalian target of rapamycin phosphorylation in old muscles at 10 days postinjury. Our results suggest that formoterol improves structural and functional regenerative capacity of regenerating skeletal muscles from aged rats by increasing protein synthesis via mammalian target of rapamycin activation. Furthermore, formoterol may have therapeutic benefits in recovery following muscle damage in senescent individuals.
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Objective: To evaluate the effect of vitamin D-3 on cytokine levels, regulatory T cells, and residual beta-cell function decline when cholecalciferol (vitamin D-3 administered therapeutically) is given as adjunctive therapy with insulin in new-onset type 1 diabetes mellitus (T1DM). Design and Setting: An 18-month (March 10, 2006, to October 28, 2010) randomized, double-blind, placebo-controlled trial was conducted at the Diabetes Center of Sao Paulo Federal University, Sao Paulo, Brazil. Participants: Thirty-eight patients with new-onset T1DM with fasting serum C-peptide levels greater than or equal to 0.6 ng/mL were randomly assigned to receive daily oral therapy of cholecalciferol, 2000 IU, or placebo. Main Outcome Measure: Levels of proinflammatory and anti-inflammatory cytokines, chemokines, regulatory T cells, hemoglobin A(1c), and C-peptide; body mass index; and insulin daily dose. Results: Mean (SD) chemokine ligand 2 (monocyte chemoattractant protein 1) levels were significantly higher (184.6 [101.1] vs 121.4 [55.8] pg/mL) at 12 months, as well as the increase in regulatory T-cell percentage (4.55%[1.5%] vs 3.34%[1.8%]) with cholecalciferol vs placebo. The cumulative incidence of progression to undetectable (<= 0.1 ng/mL) fasting C-peptide reached 18.7% in the cholecalciferol group and 62.5% in the placebo group; stimulated C-peptide reached 6.2% in the cholecalciferol group and 37.5% in the placebo group at 18 months. Body mass index, hemoglobin A(1c) level, and insulin requirements were similar between the 2 groups. Conclusions: Cholecalciferol used as adjunctive therapy with insulin is safe and associated with a protective immunologic effect and slow decline of residual beta-cell function in patients with new-onset T1DM. Cholecalciferol may be an interesting adjuvant in T1DM prevention trials.
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The in situ complexation between 2,3,5,6-tetra(2-pyridyl)pyrazine (tppz) molecules and europium ions at the air-liquid interface by means of mixed 1-octadecanol Langmuir films is reported. These films were transferred to solid supports by means of the Langmuir-Blodgett (LB) technique. The EDS maps attested the homogeneity of the LB films as well as the presence of the europium ions. The mixed alcohol/tppz LB film contained a larger amount of europium ions as compared to the pure octadecanol LB film. This work reports the production of a thin luminescent Eu3+ film containing europium ions using only alcohol molecules as ligands an unexpected result, since it is well known that there is an occurrence of non-radiative deactivation of excited europium by hydroxyl groups. Europium ion multiple binding sites were detected from lifetime decay measurements of these films in the presence of tppz molecules. (C) 2012 Elsevier B.V. All rights reserved.
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A study was designed to investigate the molecular epidemiology of extended-spectrum -lactamase (ESBL)-producing Klebsiella pneumoniae isolated in a centralized region over a 10 year period (200009). Molecular characterization was done using isoelectric focusing, PCR and sequencing for bla(CTX-M), bla(TEM) and bla(SHV) genes and plasmid-mediated quinolone resistance determinants. Genetic relatedness was determined with PFGE using XbaI and multilocus sequencing typing. A total of 89 patients with incident infections were identified; the majority presented with hospital-onset urinary tract infections. The absolute number of ESBL-producing isolates remained very low until 2003, increased slightly in 2004, remained stable until 2008 and then in 2009 there was an abrupt increase in the numbers of ESBL producers identified. The majority of K. pneumoniae produced CTX-M-14 and -15, and have replaced SHV-12-producing isolates since 2005. We identified four different major sequence types (STs) among 32 of isolates (i.e. ST17, ST20, and the new ST573 and ST575) and provided insight into their clinical and molecular characteristics. The ST isolates were more likely to produce community-onset infections, were associated with bla(CTX-M) and emerged during the latter part of the study period. ST17 produced CTX-M-15 and SHV-12, and was more likely to be positive for qnrB; ST20 produced CTX-M-14 and was positive for qnrS. The multiresistant ST575 that produced CTX-M-15 appeared in 2009. Our study highlights the importance of molecular epidemiology in providing insight into the emergence, characteristics and distribution of STs among ESBL-producing K. pneumoniae.
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The synthesis and photoluminescent properties of Ln(III)-thenoyltrifluoroacetonate and dibenzoylmethanate complexes (Ln = Eu(III) and Gd(III) ions) containing tertiary amides such as dimethylacetamide (DMA), dimethylformamide (DMF), and dimethylbenzamide (DMB) as neutral ligands are reported. The Ln complexes were characterized by elemental analysis, complexometric titration with EDTA, and infrared spectroscopy. Single-crystal X-ray structure data of the [Eu(DBM)(3).(DMA)] compound indicates that this complex crystallizes in the triclinic system, space group PT with the following cell parameters: a = 10.2580(3) angstrom, b = 10.3843(2) angstrom, c= 22.3517(5) angstrom, alpha = 78.906(2)degrees, beta = 78.049(2)degrees, lambda= 63.239(2)degrees, V= 2066.41(9) angstrom(3), and Z = 2. The coordination polyhedron for the Eu(III) complex may be described as an approximate C-2v distorted monocapped trigonal prism. The optical properties of the Eu(III) complexes were studied based on the intensity parameters and luminescence quantum yield (q). The values of the ohm(2) parameter of the Eu-DBM complexes are larger than those for the Eu-TTA complexes, indicating that the Eu(III) ion is in a more polarizable chemical environment in the former case. The geometries of the complexes have been optimized by using the Sparkle Model, and the results have been used to perform theoretical predictions of the ligand-to-metal energy transfer via direct and exchange Coulomb mechanisms. (C) 2012 Elsevier Ltd. All rights reserved.
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BACKGROUND AND PURPOSE The bed nucleus of the stria terminalis (BNST) is a limbic structure that is involved in the expression of conditioned contextual fear. Among the numerous neural inputs to the BNST, noradrenergic synaptic terminals are prominent and some evidence suggests an activation of this noradrenergic neurotransmission in the BNST during aversive situations. Here, we have investigated the involvement of the BNST noradrenergic system in the modulation of behavioural and autonomic responses induced by conditioned contextual fear in rats. EXPERIMENTAL APPROACH Male Wistar rats with cannulae bilaterally implanted into the BNST were submitted to a 10 min conditioning session (6 footshocks, 1.5 ma/ 3 s). Twenty-four hours later freezing and autonomic responses (mean arterial pressure, heart rate and cutaneous temperature) to the conditioning box were measured for 10 min. The adrenoceptor antagonists were administered 10 min before the re-exposure to the aversive context. KEY RESULTS L-propranolol, a non-selective beta-adrenoceptor antagonist, and phentolamine, a non-selective a-adrenoceptor antagonist, reduced both freezing and autonomic responses induced by aversive context. Similar results were observed with CGP20712, a selective beta 1-adrenoceptor antagonist, and WB4101, a selective a1-antagonist, but not with ICI118,551, a selective beta 2-adrenoceptor antagonist or RX821002, a selective a2-antagonist. CONCLUSIONS AND IMPLICATIONS These findings support the idea that noradrenergic neurotransmission in the BNST via a1- and beta 1-adrenoceptors is involved in the expression of conditioned contextual fear.
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Xyloglucan is a major structural polysaccharide of the primary (growing) cell wall of higher plants. It consists of a cellulosic backbone (beta-1,4-linked glucosyl residues) that is frequently substituted with side chains. This report describes Aspergillus nidulans strain A773 recombinant secretion of a dimeric xyloglucan-specific endo-beta-1,4-glucanohydrolase (XegA) cloned from Aspergillus niveus. The ORF of the A. niveus xegA gene is comprised of 714 nucleotides, and encodes a 238 amino acid protein with a calculated molecular weight of 23.5 kDa and isoelectric point of 4.38. The optimal pH and temperature were 6.0 and 60 degrees C, respectively. XegA generated a xyloglucan-oligosaccharides (XGOs) pattern similar to that observed for cellulases from family GH12, i.e., demonstrating that its mode of action includes hydrolysis of the glycosidic linkages between glucosyl residues that are not branched with xylose. In contrast to commercial lichenase, mixed linkage beta-glucan (lichenan) was not digested by XegA, indicating that the enzyme did not cleave glucan beta-1,3 or beta-1,6 bonds. The far-UV CD spectrum of the purified enzyme indicated a protein rich in beta-sheet structures as expected for GH12 xyloglucanases. Thermal unfolding studies displayed two transitions with mid-point temperatures of 51.3 degrees C and 81.3 degrees C respectively, and dynamic light scattering studies indicated that the first transition involves a change in oligomeric state from a dimeric to a monomeric form. Since the enzyme is a predominantly a monomer at 60 degrees C. the enzymatic assays demonstrated that XegA is more active in its monomeric state. (c) 2012 Elsevier B.V. All rights reserved.
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Purpose: To evaluate the effectiveness and safety of postoperative low single-dose of beta-irradiation (beta-RT) in pterygium comparing conjunctival autograft (CAG) surgery with CAG plus adjuvant beta-RT in a randomized clinical trial. Methods: This trial was designed as a prospective, randomized, single-center study. Surgery was performed in all cases according to the CAG technique. One hundred and eight pterygia were post-operatively randomized to CAG + beta-RT or CAGalone. In the case of beta-RT, a (90) Sr eye applicator was used to deliver 10 Gy to the sclera surface at a dose rate of between 200 and 250 cGy/min. After treatment, both an ophthalmologist and a radiation oncologist performed the follow-up examinations. The accumulated data were analyzed using a group sequential test. Results: Between February 2008 and September 2008, 116 eyes with primary pterygium were operated on according to the trial protocol. Adjuvant treatment was performed within 24 h post-operatively. Eight patients were lost to follow-up, resulting in 108 patients who could be analyzed. At a mean follow-up of 18 months (range, 8-33), in the 54 eyes randomized to receive CAG + beta-RT, 5 relapses occurred compared with 12 recurrences in the 54 eyes in CAG, for a crude control rate of 90.8 % vs. 78%; p = 0.032, respectively. The treatment complications as hyperemia, total dehiscence of the autograft and dellen were significantly more frequent in the CAG (p < 0.05). The arm of beta-RT resulted in better cosmetic results and improves of symptoms than CAG. Conclusions: A low single-dose of beta-RT of 10 Gy after CAG surgery was a simple, effective, and safe treatment that reduced the risk of primary pterygium recurrence, improved symptoms after surgery, resulting in a better cosmetic effect than only CAG. (C) 2012 Elsevier Inc.
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In this study alpha and beta diversity patterns of five leaf litter arthropod groups (ants, predatory ants, oribatid mites, spiders and other arachnids) were described and compared in 39 sampling patches of a transformed landscape in southwestern Colombia, that represented five vegetation types: secondary forest, riparian forest, giant bamboo forest, pasture and sugarcane crop. It was also assessed whether some taxa could be used as diversity surrogates. A total of 6,765 individuals grouped in 290 morphospecies were collected. Species richness in all groups was lower in highly transformed vegetation types (pasture, sugarcane crop) than in native ones (forests). In contrast, there were no clear tendencies of beta diversity among vegetation types. Considering sampling patches, 0.1-42% of the variation in alpha diversity of one taxonomic group could be explained from the alpha diversity of another, and 0.2-33% of the variation of beta diversity of a given taxon was explained by that in other groups. Contrary to recent findings, we concluded that patterns of alpha diversity are more congruent than patterns of beta diversity. This fact could be attributed to a sampling effect that promotes congruence in alpha diversity and to a lack of a clear regional ecological gradient that could promote congruent patterns of beta diversity. We did not find evidence for an ideal diversity surrogate although diversity patterns of predatory ants had the greatest congruencies. These results support earlier multi-taxon evaluations in that conservation planning should not be based on only one leaf litter arthropod group.
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Based on the premise of symbiotic control, we genetically modified the citrus endophytic bacterium Methylobacterium extorquens, strain AR1.6/2, and evaluated its capacity to colonize a model plant and its interaction with Xylella fastidiosa, the causative agent of Citrus Variegated Chlorosis (CVC). AR1.6/2 was genetically transformed to express heterologous GFP (Green Fluorescent Protein) and an endoglucanase A (EglA), generating the strains ARGFP and AREglA, respectively. By fluorescence microscopy, it was shown that ARGFP was able to colonize xylem vessels of the Catharanthus roseus seedlings. Using scanning electron microscopy, it was observed that AREglA and X. fastidiosa may co-inhabit the C. roseus vessels. M. extorquens was observed in the xylem with the phytopathogen X. fastidiosa, and appeared to cause a decrease in biofilm formation. AREglA stimulated the production of resistance protein, catalase, in the inoculated plants. This paper reports the successful transformation of AR1.6/2 to generate two different strains with a different gene each, and also indicates that AREglA and X. fastidiosa could interact inside the host plant, suggesting a possible strategy for the symbiotic control of CVC disease. Our results provide an enhanced understanding of the M. extorquens-X. fastidiosa interaction, suggesting the application of AR1.6/2 as an agent of symbiotic control.
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The progression of carcinogenesis entails the detachment of cells, invasion and migration of neoplastic cells. Alterations in epithelial adhesion and basement membrane proteins might mediate the early stages of carcinogenesis. This study investigated the expression of adhesion molecules and the basement membrane protein laminin-5 in actinic cheilitis (AC) and incipient squamous cell carcinoma of the lower lip to understand early photocarcinogenesis. Ln-5 gamma 2 chain as well as alpha 3, beta 1 subunits of alpha 3 beta 1 heterodimer and beta 4 subunit of integrin alpha 6 beta 4 were evaluated by immunohistochemistry in 16 cases of AC and 16 cases of superficially invasive squamous cell carcinoma (SISCC). Most AC cases showed reduced expression of beta 1, beta 4 and alpha 3 integrins, and SISCCs lacked beta 1, beta 4 and alpha 3 integrins in the invasive front. AC cases were negative for the Ln-5 gamma 2 chain. Five cases of SISCC (31%) showed heterogeneous Ln-5 gamma 2 chain expression in the invasive front of the tumor. Integrin beta 1, beta 4 and alpha 3 expression is lost during the early stages of lip carcinogenesis. Expression of Ln-5 gamma 2 in the invasive front in cases and its correlation with tumor progression suggest that it mediates the acquisition of the migrating and invading epithelial cell phenotype. (C) 2012 Elsevier GmbH. All rights reserved.
VEGF-C expression in oral cancer by neurotransmitter-induced activation of beta-adrenergic receptors
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The aim of this study was to investigate the expression of vascular endothelial growth factor type C (VEGF-C) in oral squamous cell carcinoma (OSCC) cell lines through norepinephrine-induced activation of beta-adrenergic receptors. Human OSCC cell lines (SCC-9 and SCC-25) expressing beta-adrenergic receptors were stimulated with different concentrations of norepinephrine (0.1, 1, and 10 μM) and 1 μMof propranolol, and analyzed after 1, 6, and 24 h. VEGF-C gene expression and VEGF-C production in the cell supernatant were evaluated by real-time PCR and by ELISA, respectively. The results showed that beta-adrenergic receptor stimulation by different concentrations of norepinephrine or blocking by propranolol did not markedly alter VEGF-C expression by SCC-9 and SCC-25 cells. VEGF-C protein levels produced by oral malignant cell lines after stimulation with different norepinephrine concentrations or blocking with propranolol was statistically similar (p>0.05) to those of the control group (nonstimulated OSCC cell lines). Our findings suggest that stimulation of beta-adrenergic receptors by means of norepinephrine does not seem to modulate the VEGF-C expression in OSCC cell lines. These findings reinforce the need for further studies in order to understand the responsiveness of oral cancer to beta-adrenergic receptor stimulation or blockage, especially with regard to VEGF-C production.