908 resultados para modification of macromolecules
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The objective of this study was to estimate (co)variance components using random regression on B-spline functions to weight records obtained from birth to adulthood. A total of 82 064 weight records of 8145 females obtained from the data bank of the Nellore Breeding Program (PMGRN/Nellore Brazil) which started in 1987, were used. The models included direct additive and maternal genetic effects and animal and maternal permanent environmental effects as random. Contemporary group and dam age at calving (linear and quadratic effect) were included as fixed effects, and orthogonal Legendre polynomials of age (cubic regression) were considered as random covariate. The random effects were modeled using B-spline functions considering linear, quadratic and cubic polynomials for each individual segment. Residual variances were grouped in five age classes. Direct additive genetic and animal permanent environmental effects were modeled using up to seven knots (six segments). A single segment with two knots at the end points of the curve was used for the estimation of maternal genetic and maternal permanent environmental effects. A total of 15 models were studied, with the number of parameters ranging from 17 to 81. The models that used B-splines were compared with multi-trait analyses with nine weight traits and to a random regression model that used orthogonal Legendre polynomials. A model fitting quadratic B-splines, with four knots or three segments for direct additive genetic effect and animal permanent environmental effect and two knots for maternal additive genetic effect and maternal permanent environmental effect, was the most appropriate and parsimonious model to describe the covariance structure of the data. Selection for higher weight, such as at young ages, should be performed taking into account an increase in mature cow weight. Particularly, this is important in most of Nellore beef cattle production systems, where the cow herd is maintained on range conditions. There is limited modification of the growth curve of Nellore cattle with respect to the aim of selecting them for rapid growth at young ages while maintaining constant adult weight.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Objective: HIV infection is exacerbated through additional pro-atherogenic mechanisms related to the processes of immune activation, inflammation, coagulation, and the modification of lipoproteins (e.g., particles of high density lipoprotein), contributing to increased cardiovascular risk. The aim of this study was to analyze the serum concentrations of myeloperoxidase (MPO) and other laboratory parameters in HIV-infected patients treated or not with antiretroviral drugs compared to non-infected individuals.Materials/Methods: The study included 154 volunteers: 47 non-infected individuals (control group - CON), 27 infected and untreated individuals (NTARv group) and 80 treated individuals (TARV group). We analyzed the counts of CD4+ lymphocytes and the viral load of the infected patients, along with the blood count, fasting glucose, total serum cholesterol (CHOL), HDL cholesterol, LDL cholesterol, triglycerides, MPO and high-sensitivity C-reactive protein (CRP) of all study participants.Results: There were significant increases in glucose, CHOL, LDL cholesterol, and triglycerides in the TARV group and significant reductions in the levels of HDL cholesterol for the TARV and NTARV groups. Significantly elevated levels of Hs-CRP were observed only in the TARV group, while levels of MPO were significantly higher in the TARV and NTARV groups compared to the control group. A correlation of MPO with Hs-CRP (r = 0.21, p = 0.032) was observed for HIV-infected patients, but MPO did not correlate significantly with the other analyzed parameters.Conclusions: The investigation of early biomarkers for cardiovascular risk evaluation, such as MPO, contributes to the clinical monitoring of HIV-infected individuals. The serum levels of MPO correlated with Hs-CRP and were high in HIV-infected individuals, indicating a possible predictor of cardiovascular events in these patients. (c) 2012 Elsevier B.V. All rights reserved.
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Polymer films, deposited from acetylene and argon plasma mixtures, were bombarded with 150 keV He+ ions, varying the fluence, Phi, from 10(18) to 10(21) ions/m(2). Molecular structure and optical gap of the samples were investigated by infrared and ultraviolet-visible spectroscopies, respectively. Two-point probe was employed to determine the electrical resistivity while hardness was measured by nanoindentation technique. It was verified modification of the molecular structure and composition of the films. There was loss of H and increment in the concentration of unsaturated carbon bonds with Phi. Optical gap and electrical resistivity decreased while hardness increased with Phi. Interpretation of these results is proposed in terms of chain crosslinking and unsaturation. (C) 2002 Elsevier B.V. B.V. All rights reserved.
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Plasma treatments are frequently employed to modify surface properties of materials such as adhesivity, hydrophobicity, oleophobicity etc. Present work deals with surface modification of common commercial polymers such as polyethylene terephthalate (PET) and polyurethane (PU) by an air dielectric barrier discharge (DBD) at atmospheric pressure. The DBD treatment was performed in a plain reactor in wire-duct geometry (non-uniform field reactor), which was driven by a 60 Hz power supply. Material characterization was carried out by water contact angle measurements, atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The plasma-induced modifications are associated with incorporation of polar oxygen and nitrogen containing groups on the polymer surface. The AFM analysis reveals that the plasma treatment roughens the material surface. Due to these structural and morphological changes the surface of DBD-treated polymers becomes more hydrophilic resulting in enhanced adhesion properties. (C) 2010 Elsevier B.V. All rights reserved.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The rat tapeworm, Hymenolepis diminuta, induces mastocytosis, hypertrophy of enteric smooth muscle, alteration of enteric myoelectric activity, and slowed enteric transit of the rat host's intestine. This report examines the resolution of both tapeworm-induced mastocytosis and tissue changes during the period following removal of the tapeworm with Praziquantel (PZQ). The dynamics of the mucosal mast cell (MMC) population following removal of the tapeworms was assessed by histochemical identification of MMC and morphometric techniques. As a possible mechanism of MMC population regulation, MMC apoptosis was examined over the same experimental period using the in situ nick end labeling of fragmented DNA (TUNEL). Shifts in MMC numbers were correlated with functional and morphological changes of the intestine following removal of the adult-stage tapeworm. Ileal tissues from rats infected 32 days with H. diminuta (the beginning of plateau phase of tapeworm-induced chronic mastocytosis) were harvested 1, 2, 3, and 4 weeks after the PZQ treatment. Control ilea were obtained either from rats which were never infected and never treated with PZQ or from rats infected with H, diminuta for 32 days but not treated with PZQ. In order to detect MMC and apoptosis, tissue sections of ileum were doubled stained sequentially with Astra blue for MMC granules followed by a modification of the TUNEL technique. No alteration in MMC numbers were observed in PZQ-treated animals until 3 weeks after the removal of the tapeworms. The decline of MMC occurred in the mucosa and submucosa. MMC numbers first approached uninfected control levels at 4 weeks posttreatment. Coincident with the decline in mucosal MMC numbers, the rate of MMC entering apoptosis also declined. Simultaneously, ileal smooth muscle layers, hypertrophied by infection, and mucosal structures began the process of involution and atrophy. Apoptosis of MMC in the submucosa and muscularis mucosa was not detected. In conclusion, H. diminuta elicited mastocytosis and increased thickness of both mucosa and muscularis externa do not begin a decline toward control Values until 3 weeks after the parasites are gone and normal intestinal motility is restored. These data are consistent with the lack of MMC mediation of altered motility, and the decline in the rate of MMC apoptosis at 3 weeks post-PZQ suggests that apoptosis may play an important role in the involution of tapeworm-induced mastocytosis. (C) 1999 Academic Press.
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Genomic imprinting is defined as a gamete of origin-specific epigenetic modification of DNA leading to differential gene expression in the zygote. Several imprinted genes have been identified and some of them are associated with tumor development. We investigated the expression and the imprinting status of IGF2 and H19 genes in 47 uterine leiomyomas. Using allelic transcription assay, we detected the expression of the IGF2 gene in 10 of a total of 15 informative cases. No loss of imprinting, as determined by the finding of biallelic expression, was detected in any case. The expression of H19 gene was detected in 10 of 20 informative cases and the imprinting pattern was also maintained in all of them. Our data suggest that alterations in IGF2 and H19 genes expression by loss of imprinting do not occur in uterine leiomyomas. (C) 1999 Academic Press.
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Para se detectar diferenças imuno-antigênicas entre 8 amostras de P. brasiliensis isoladas de diferentes áreas endêmicas (Botucatu: Pb 1, 2 e 3; São Paulo: Pb: 18, 192 e 265; Venezuela: Pb 9 e 73), esutdaram-se: 1. A reatividade antigênica de cada amostra nas reações de imunofluorescência indireta (II) e de imunodifusão dupla em gel de agar (ID) contra painel de 20 soros controles positivos para paracoccidioidomicose; 2. A capacidade de induzir resposta imune humoral (medida por imunodifusão) e celular (medida pelo teste de coxim plantar) em camundongos imunizados com an-tígenos de cada amostra. Observamos: 1. As amostras Pb 265 e Pb 9 mostraram-se mais reativas na II; 2. Os antígenos das amostras Pb 192 e Pb 73 foram significativamente mais reativas na ID; 3. Estes dados demonstram diferenças de antigenicidade entre estas amostras; 4. A amostra Pb 18 mostrou baixo poder indutor de resposta imune celular e alta capacidade de indução de resposta imune humoral em camundongos imunizados, revelando dissociação de sua imunogenicidade. Estas diferenças podem indicar a existência de cepas distintas do fungo ou refletir modificações do parasita no hospedeiro ou du rante seu cultivo.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Background: Chemical modification of implant surface is typically associated with surface topographic alterations that may affect early osseointegration. This study investigates the effects of controlled surface alterations in early osseointegration in an animal model.Methods: Five implant surfaces were evaluated: 1) alumina-blasting, 2) biologic blasting, 3) plasma, 4) microblasted resorbable blasting media (microblasted RBM), and 5) alumina-blasting/acid-etched (AB/AE). Surface topography was characterized by scanning electron microscopy and optical interferometry, and chemical assessment by x-ray photoelectron spectroscopy. The implants were placed in the radius of six dogs, remaining 2 and 4 weeks in vivo. After euthanization, specimens were torqued-to-interface failure and non-decalcified - processed for histomorphologic bone-implant contact, and bone area fraction-occupied evaluation. Statistical evaluation was performed by one-way analysis of variance (P < 0.05) and post hoc testing by the Tukey test.Results: The alumina-blasting surface presented the highest average surface roughness and mean root square of the surface values, the biologic blasting the lowest, and AB/AE an intermediate value. The remaining surfaces presented intermediate values between the biologic blasting and AB/AE. The x-ray photoelectron spectroscopy spectra revealed calcium and phosphorus for the biologic blasting and microblasted RBM surfaces, and the highest oxygen levels for the plasma, microblasted RBM, and AB/AE surfaces. Significantly higher torque was observed at 2 weeks for the microblasted RBM surface (P < 0.04), but no differences existed between surfaces at 4 weeks (P > 0.74). No significant differences in bone-implant contact and bone area fraction-occupied values were observed at 2 and 4 weeks.Conclusion: The five surfaces were osteoconductive and resulted in high degrees of osseointegration and biomechanical fixation. J Periodontol 2011;82:742-750.
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For the first time, a non-catalytic and myotoxic Lys49-PLA(2) (BthTX-I from Bothrops jararacussu venom) has been crystallized with BPB inhibitor. X-ray diffraction data were collected and electron-density calculations showed that the ligand is bound to the His48 residue. BthTX-I with His48 chemically modified by BPB shows strongly reduced myotoxic and cytotoxic activities. This suggests a biological correlation between the modification of His48, which is associated with catalytic activity of PLA(2)s, and other toxicological activities of Lys49-PLA(2)s.