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Estudo de EquilÃbrio e CinÃtica de AdsorÃÃo em Resinas de Troca IÃnica Aplicado à SeparaÃÃo CromatogrÃfica ContÃnua de Frutose e Glicose do Xarope de Caju / Studies on adsorption equilibrium and kinetics in ion exchange resins applied to the continuous chromatographic separation of fructose and glucose present in cashew apple syrupJosy Eliziane Torres Ramos 31 March 2008 (has links)
FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / A cajucultura à considerada uma das atividades sÃcio-econÃmicas mais importantes
da regiÃo Nordeste do Brasil. Apesar de ser empregado industrialmente para fabricaÃÃo de
polpa, bebidas e doces, o pedÃnculo do caju apresenta altÃssimos nÃveis de desperdÃcio.
Pouco mais de 10% da produÃÃo agrÃcola à explorada comercialmente. Neste contexto, a
obtenÃÃo de produtos de valor agregado a partir do pedÃnculo do caju â como xaropes de
frutose e glicose â pode indicar rotas econÃmicas alternativas para as regiÃes produtoras,
aproveitando a produÃÃo excedentÃria nÃo absorvida pelo mercado de sucos e doces
industrializados. O leito mÃvel simulado constitui uma das mais inovadoras tecnologias
cromatogrÃficas que realiza separaÃÃo de isÃmeros de forma contÃnua. Um dos pontoschave
desta tecnologia à a escolha adequada das condiÃÃes de operaÃÃo (vazÃes e tempos
de troca) que propiciem uma separaÃÃo adequada. Este trabalho apresenta estudos de
equilÃbrio de adsorÃÃo de soluÃÃes sintÃticas de frutose e glicose, em condiÃÃes de
sobrecarga de concentraÃÃo, visando à separaÃÃo destes aÃÃcares em leito mÃvel simulado
para a produÃÃo de xaropes de caju enriquecidos em frutose e glicose. As isotermas de
adsorÃÃo foram obtidas por cromatografia frontal, utilizando soluÃÃes sintÃticas de frutose e
glicose com concentraÃÃo variando de 10 a 120g/L, nas temperaturas de 30, 40 e 60 ÂC,
utilizando as resinas de troca iÃnica Dowex MTO 99Ca e Diaion UBK 555. As curvas de
ruptura (breakthrough) das soluÃÃes sintÃticas foram confrontadas com curvas de
breakthrough obtidas a partir do xarope de caju para validaÃÃo do modelo. A partir das
mesmas, foram obtidas isotermas nÃo-lineares bem descritas pelo modelo de Langmuir. O
modelo do transporte dispersivo foi empregado para reproduzir o comportamento das
curvas de breakthrough e para estimar parÃmetros de transferÃncia de massa, utilizando o
solver comercial gPROMS. Os dados de equilÃbrio de adsorÃÃo foram utilizados para gerar
a regiÃo de completa separaÃÃo (razÃes de vazÃo nas zonas 2 e 3) em uma unidade de leito
mÃvel simulado (LMS), com base na Teoria do EquilÃbrio (mÃtodo do triÃngulo) para
prediÃÃo das condiÃÃes de operaÃÃo numa unidade piloto. / The cashew crop is considered one of the most important socio-economic activity in
Northeastern Brazil. Despite being used industrially for the production of pulp, drinks and
sweets, the cashew apple shows high levels of waste. A little more than 10% of crop is
exploited commercially. In this context, adding value to products derived from the cashew
apple - such as fructose and glucose syrups - may indicate alternative economical routes for
producing regions, by consuming the surplus not absorbed by the market of juices and
sweets. The simulated moving bed is one of the most innovative technologies that performs
continuous chromatographic separation of isomers. One of the key points of this technology
is the choice of operating conditions (flows and switching times) that provides adequate
separation. This work presents studies of adsorption equilibrium of synthetic solutions of
fructose and glucose, under overloaded conditions of concentration, aiming at the
separation of these sugars in simulated moving bed for the production of high-fructose and
high-glicose syrups. The adsorption isotherms were obtained by frontal analysis, using
synthetic solutions with fructose and glucose concentrations ranging from 10 to 120g / L, at
temperatures of 30, 40 and 60 Â C, using the ion exchange resins Dowex MTO 99Ca and
Diaion UBK 555. The breakthrough curves of synthetic solutions were compared with
those obtained from the cashew syrup for validation of data, tha sake of model validation.
Tha measured isotherms were non-linear and well described by the Langmuir model. The
dispersive transport model was used to reproduce the behavior of breakthrough curves and
to estimate mass transfer parameters, using the gPROMS commercial solver. Adsorption
data were used to generate the region of complete separation (flowrate ratios in sections 2
and 3) of a simulated moving bed (SMB unit), based on the equilibrium theory (the triangle
method), in order to predict operating conditions in a pilot unit.
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Effects of Physical Activity on the Performance of 24-h Urinary Sucrose and Fructose as a Biomarker of Total Sugars IntakeJanuary 2019 (has links)
abstract: Urinary sucrose and fructose has been suggested as a predictive biomarker of total sugars intake based on research involving UK adults. The purpose of this study was to determine the association between total sugars consumption and 24-hour urinary sucrose and fructose (24uSF) in US adult population and to investigate the effect of physical activity on this association. Fifty seven free-living healthy subjects 20 to 68 years old, participated in a 15-day highly controlled feeding study, consuming their habitual diet, provided by the research metabolic kitchen. Dietary sugars were estimated using Nutrition Data System for Research (NDSR). Subjects collected eight 24-hour urine samples measured for urinary sucrose and fructose. Physical activity was assessed daily using a validated 15-day log that inquired about 38 physical activities across six domains; home activities, transportation, occupation, conditioning, sports and leisure. The mean total sugars intake and added sugars intake of the sample was 112.2 (33.1) g/day and 65.8 (29.0) g/day (9.7%EI), respectively. Significant moderate positive correlation was found between 15-d mean total sugars intake and 8-day mean 24uSF (r = 0.56, p < 0.001). Similarly, added sugars were moderately correlated with 24uSF (r = 0.56, p < 0.001), while no correlation was found between naturally-occurring sugars and 24uSF (r = 0.070, p < 0.001). In a linear multiple regression, total and added sugars each explained 30% of variability in 24uSF (Adjusted R2, p value; total sugars: 0.297, 0.001; added sugars: 0.301, p < 0.001). Physical activity had no effect on the association between dietary and urinary sugars in neither the correlation nor the linear regression analysis. 24uSF can be used as a biomarker for total and added sugars consumption in US adults, although its predictability was weaker compared to findings involving UK adults. No evidence was found showing that physical activity levels affect the association between 24uSF and total sugars intake in US adults. More detailed investigation through future feeding studies including subjects with wide range of sugars intake and of different ethnic/racial backgrounds are needed to better understand the characteristics of the biomarker and its uses. / Dissertation/Thesis / Masters Thesis Nutrition 2019
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Etude fonctionnelle du génome de Bacillus subtilis : de nouvelles régulations transcriptionnelles du métabolisme central du carbone.Doan, Thierry 04 1900 (has links) (PDF)
Chez Bacillus subtilis, la transcription de l'opéron gapA, comprenant les gènes de la partie centrale de la glycolyse, est stimulée en présence de sources de carbone glycolytiques. Nos études in vivo et in vitro de CggR, le répresseur qui contrôle cette stimulation, ont démontré d'une part que celui-ci a la capacité de se lier à une séquence d'ADN inhabituellement longue, consistant en une répétition directe de deux motifs (CGGGACN6TGTCN4CGGGACN6TGTC) et située entre le promoteur et le codon d'initiation de l'opéron cggR-gapA, et d'autre part que son activité est inhibée par le fructose-1,6-biphosphate. Des analyses de séquence et des expériences de transcriptome ont indiqué que CggR, qui est très conservé chez les bactéries à Gram positif et qui définit une sous-famille de la famille de régulateurs transcriptionnels SorC/DeoR, est spécialisé dans le contrôle des gènes de la glycolyse. Ainsi, une collaboration a été engagée avec des structuralistes (CBS, Montpellier) pour aller plus loin dans la connaissance de ce prototype d'une famille encore peu connue de régulateurs. Deux paires de gènes paralogues ont été détectés dans le génome (ywkA et malS, ytsJ et mleA) dont les produits sont homologues à des enzymes maliques. L'analyse transcriptomique globale d'une souche sauvage cultivée en présence de glucose ou de malate comme seule source de carbone montre que l'expression d'ywkA est induite en présence de malate. En collaboration avec l'équipe de Y. Fujita, nous avons montré qu'ywkA codait bien une enzyme malique NADdépendante dont l'expression est spécifiquement induite par le malate extracellulaire et insensible à la répression catabolique. De plus, nous avons montré que le système à deux composants YufL-YufM active directement la transcription d'ywkA en présence de malate. Cependant, YwkA n'est pas requis pour la croissance en présence de malate comme seule source de carbone. La technique d'analyse du transcriptome au moyen de membranes à haute densité est maintenant acquise au laboratoire. Nous avons commencé à mettre à profit cet outil pour une étude globale de l'expression génique en fonction de différentes sources de carbone.
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Colour development in Pinus radiata D. Don. under kiln-drying conditions.Dieste, Andrés January 2002 (has links)
This study quantifies discolouration on the surface of Pinus radiata boards during kiln drying, particularly kiln brown stain (KBS), and models it as a function of chemical compounds present in the wood closest to the surface. The discolouration was investigated with two experimental factors: drying time, which consisted in drying at 70/120 ℃ for 0, 8, 16 and 24 hours; and leaching, done at three levels, noleaching, mild and severe, to reduce the soluble compounds present in wood suspected of developing coloured compounds. The colour change was quantified using a reflectance photometer (colour system CIE Yxy, brightness) and by the analysis of digital photographs (colour system CIE Lab). The chemical analysis of the wood closest to the surface of the boards determined fructose, glucose, sucrose (HPLC), total sugar (sum of fructose, glucose and sucrose), total nitrogen (combustion gas analysis), and phenols discriminated by molecular weight (Folin-Ciocalteu method). In the cause-effect analysis, colour was the dependent variable, and drying time and the determinations of chemical compounds were independent variables. After statistical analysis (ANOVA and MANOVA) the dependent variables to be included in the models were luminance factor (Y), brightness (R457 and the blue-to-yellow scale of CIE Lab (b); and the independent variables were drying time, nitrogen, total sugar, and high-molecular-weight phenols. Linear (multivariate regression) and non-linear models (Neural Networks) showed that discolouration during kiln drying was best predicted when the luminance factor (Y) was used to quantify colour change as a function of the content of nitrogen-containing compounds and drying time. Furthermore, the data were fitted into an empirical model based on simple reaction kinetics that considered the rate of discolouration as a function of nitrogen concentration. The results suggest that nitrogen could act as a limiting reactant in Maillard-type reactions that produce colour during kiln drying.
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Implication du pore de transition de perméabilité mitochondriale dans l'apoptose des cellules β pancréatiquesCornali, Sandrine 03 April 2012 (has links) (PDF)
Implication du PTP dans la mort cellulaire β pancréatique L'hyperglycémie, l'hyperfructosémie et l'ischémie-reperfusion sont délétères pour la viabilité cellulaire β pancréatique, jouant un rôle majeur dans la perte de la masse cellulaire β. Le pore de transition de perméabilité mitochondriale (PTP) est un canal mitochondrial impliqué dans le déclenchement de la mort cellulaire. Des données récentes montrent l'implication du PTP et du stress oxydant dans la toxicité induite par l'ischémie-reperfusion sur cardiomyocytes et également dans la glucotoxicité induite sur cellules endothéliales. La première partie de notre étude a visé à étudier l'implication de l'ouverture du PTP dans la mort cellulaire des cellules INS-1 et des îlots pancréatiques humains soumis à de fortes concentrations de glucose et de fructose. Nous démontrons que l'incubation des cellules INS-1 et des îlots pancréatiques humains en présence de 30 mM de glucose ou 2,5 mM de fructose déclenche une ouverture du PTP et induit la mort cellulaire. La metformine et la Cyclosporine A (CsA) préviennent l'ouverture du PTP et la mort cellulaire induite par le glucose et le fructose. La deuxième partie de notre travail montre que l'exposition des INS-1 à une heure de carence en substrat concomitante d'une hypoxie, suivie d'une restauration des conditions basales conduit à l'ouverture du PTP et à une majoration drastique de la mort cellulaire. Ces deux évènements sont totalement prévenus par l'incubation préalable par la CsA et la metformine mais aussi par la N-Acétyl-Cystéine (NAC) ou par l'exposition à une anoxie, soulignant ainsi le rôle fondamental du stress oxydant dans le déclenchement de l'ouverture du PTP et de la mort cellulaire. Nous montrons qu'au cours de l'ischémie-reperfusion simulée, la production de superoxide est bi-phasique : nous décrivons un premier pic de production au cours de la carence en substrat, lié à un flux reverse d'électrons au sein du complexe I de la chaîne respiratoire. Ce premier pic est suivi d'un deuxième pic de production après la restauration du niveau de substrats et d'O2, lié à l'ouverture du PTP. La NAC, l'anoxie ou la metformine préviennent les deux pics de production de superoxide tandis que la CsA prévient seulement le second pic. Enfin, nous montrons que l'hypoxie seule n'induit ni stress oxydant, ni ouverture du PTP ni mortalité cellulaire. L'ensemble de notre travail démontre le rôle central du PTP dans la gluco-fructotoxicité et dans la toxicité induite par l'ischémie-reperfusion sur la cellule β pancréatique. Ainsi, prévenir l'ouverture du PTP peut-être une approche intéressante pour préserver la viabilité cellulaire β.
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Wavelet based dynamic modelling of simulated moving bed chromatographic processesYao, Hong Mei January 2009 (has links)
Simulated moving bed chromatography process (SMBCP) is the technical realisation of a countercurrent adsorption process through the cyclic port switching. SMB technology reduces the cost of packing material with high loading capacity and provides high purity and high recovery in a very short time. Major commodity applications have been found in the petroleum, food, biotechnology, pharmaceutical and fine chemical industries. The industrial applications bring an emergent demand to improve the SMBCP operation for higher product quality, productivity, efficiency and robustness. However, for this particular process, we encounter several challenges. Firstly, the interplay of the effects of strong nonlinearities, competition of solutes, mass transfer resistance and fluid dynamic dispersion produces steep concentration fronts. Mathematical model accounted for this particular property constitutes a serious difficulty for the solution procedure. Secondly, a dynamic SMB model consists of a set of partial differential, ordinary differential and algebraic equations, which are highly coupled. The large size is a problem due to its intensive computation when on-line optimisation and real-time control are necessary. Thirdly, the SMB unit operation exhibits complex dynamics. Process metrics for design and operation can be determined only when a cyclic steady state is reached after a certain number of switching. Achieving this steady state by solving the PDE models cycle after cycle involves expensive calculation. Studies have been carried out to solve these problems through process analysis, investigation on spatial discretisation techniques, and development of an accelerated integration scheme. / Through a systematic study on the advances of SMB modelling, design and control, a set of functionally equivalent models for SMBCP are identified and summarized for their practical applications. The limitations of the existing modelling techniques in industrial applications are also identified. Furthermore, structural analysis of the existing models is conducted for a better understanding of the functionality and suitability of each model. Suggestions are given on how to choose an appropriate model with sufficient accuracy while keeping the computational demand reasonably low for real time control. / Effort is made on to the systematic investigation of different numerical methods for the solution of PDEs to circumvent the steep gradients encountered in chromatographic separation. Comprehensive studies are conducted on a single column chromatographic process represented by a transport-dispersive-equilibrium linear model. Numerical solutions from the upwind-1 finite difference, wavelet-collocation, and high resolution methods are evaluated by quantitative comparisons with the analytical solution for a range of Peclet numbers. It reveals that for a PDE system with a low Peclet number, all existing numerical methods work well, but the upwind finite difference method consumes the most time for the same degree of accuracy of the numerical solution. The high resolution method provides an accurate numerical solution for a PDE system with a medium Peclet number. The wavelet collocation method is capable of catching up steep changes in the solution, and thus can be used for solving PDE models with high singularity. / The advantages and disadvantages of the wavelet based approaches are further investigated through several case studies on real SMBCP system. A glucose-fructose separation process is firstly chosen with its relatively simple isotherm representations. Simulations are conducted using both wavelet collocation and upwind finite difference methods. For more complicated applications, an enantiomers separation process is selected. As the PDEs model exhibit a certain degree of singularity, wavelet collocation and high resolution methods are adopted for spatial discretisation. It is revealed that both the wavelet based approaches and high resolution methods are good candidates in terms of computation demand and prediction accuracy on the steep front. This is the first time that these two frontier numerical methods are used for such a complex SMB system models and our results are encouraging for the development of model-based online control scheme. / In developing a new scheme to rapidly obtain the solution at steady state for any arbitrary initial condition, the concept of Quasi-Envelope (QE) is adopted under the consideration that a SMBCP can be treated as a pseudo-oscillatory process because of a large number of continuous switching. The scheme allows larger steps to be taken to predict the slow change of starting state within each switching. Combined with previously developed wavelet-based technique, this method is successfully applied to the simulation of a SMB sugar separation process. Investigations are also carried out on the location of proper starting point for the algorithm and on the effect of changing stepsize to the convergence of iteration method. It is found that if the starting state of Quasi-Envelope is chosen to be the same as the original function, the multivalue algorithm would require similar computational effort to achieve the steady state prediction, regardless of the integration stepsize. If using constant stepsize, launching QE later is helpful when quasi-envelope displays steep change at the start-up period. A changing stepsize produces slow convergence compared to the constant stepsize strategy, thus increasing the work load where the stepsize change is occurring. Other iteration method is required to be imposed to achieve faster convergence right from the beginning. Potential applications can be seen for other chemical engineering processes with inherent cyclic behaviour.
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Rheological Properties of Aqueous Nanometric Alumina SuspensionsChuanping Li January 2004 (has links)
19 Dec 2004. / Published through the Information Bridge: DOE Scientific and Technical Information. "IS-T 2097" Chuanping Li. 12/19/2004. Report is also available in paper and microfiche from NTIS.
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Verfahrensentwicklung zur Synthese von 5-Hydroxymethylfurfural und Kohlenhydratcarbonsäuren auf Basis nachwachsender RohstoffeHirth, Joachim. Unknown Date (has links)
Techn. Universiẗat, Diss., 2003--Darmstadt.
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FRUTOSE-1,6-BISFOSFATO E N-ACETILCISTEÍNA ATENUAM A FORMAÇÃO DE PRODUTOS PROTEICOS DE OXIDAÇÃO AVANÇADA, UMA NOVA CLASSE DE MEDIADORES INFLAMATÓRIOS, IN VITRO / FRUCTOSE-1,6-BISPHOSPHATE AND N-ACETYLCYSTEINE ATTENUATE THE FORMATION OF ADVANCED OXIDATION PROTEIN PRODUCTS A NEW CLASS OF INFLAMMATORY MEDIATORS, IN VITROBochi, Guilherme Vargas 19 September 2012 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The assessment of biomarkers of reactions involving reactive oxygen species have the
potential not only to determine the extent of oxidative damage, but also to predict the
effectiveness of therapeutic strategies aimed at reducing or preventing the damage promoted
by oxidative stress. Recently, it has been described and characterized a new class of
compounds formed in consequence of oxidative stress, designated as advanced oxidation
protein products (AOPP). The accumulation of AOPP was first described in patients with
chronic renal failure undergoing hemodialysis and was subsequently found in diabetes,
atherosclerosis, obesity and acute renal failure. Previous studies have identified AOPP as a
new marker of oxidative damage to proteins and a new class of inflammatory mediators,
providing arange of effects at both the cellular and systemic levels. Although the mechanism
of action by which AOPP act is not fully understood, it is known that these products activate
respiratory burst in phagocytes, including neutrophils and monocytes, through the activation
of enzymes present in these cells. Furthermore, it has been demonstrated that AOPP may
promot these effects (pro-oxidants and pro-inflammatory) at several cell types such as
endothelial and kidney cells via activation of a signaling cascade, and in some aspects of this
cascade AOPP effects is very similar to effects caused by advanced glycation end products
(AGEs). In this context, the evaluation of the antioxidant activity of compounds in vitro
models involving the formation of AOPP may present special interest. Among these
compounds, N-acetylcysteine (NAC) and Fructose-1 ,6-bisphosphate (FBP) may be
promising substances for this purpose. The NAC is a sulfhydryl donor group very similar to
the amino acid cysteine and FBP is a highly energetic intermediate metabolite of glycolysis.
Thus, the aim of this study was to determine the effects of FBP and NAC, as well as the
synergistic effect of both treatments on the formation of AOPP in vitro. For this purpose,
purified human albumin was incubated with various concentrations of hypochlorous acid
(HOCl) (1, 2 and 4 mM) to produce AOPP in vitro, which was named albumin-advanced
oxidation protein products (albumin-AOPP). In this context, both FBP as NAC were able to
inhibit the formation of AOPP concentration-dependent manner, with FBP 20mg/mL and
NAC 1mg/mL were responsible for the inhibition of 64% and 85% respectively. Furthermore,
the synergistic effect promoted by the association of both compounds was more effective
ininhibiting the formation of AOPP. Therefore, FBP and NAC may be promising candidates
to mitigate or neutralize the pro-inflammatory and pro-oxidant triggered by AOPP. / A avaliação de biomarcadores das reações que envolvem as espécies reativas de
oxigênio têm potencial não apenas de determinar a extensão do dano oxidativo, mas
também de predizer a eficiência das estratégias terapêuticas destinadas a reduzir ou
prevenir os danos promovidos pelo estresse oxidativo. Recentemente, foi descrita e
caracterizada uma nova classe de compostos formados em consequência do estresse
oxidativo, designada como produtos proteicos de oxidação avançada (AOPP). O
acúmulo de AOPP foi primeiramente descrito em pacientes com insuficiência renal
crônica submetidos à hemodiálise e, posteriormente, verificou-se que este marcador está
envolvido em várias condições patológicas, incluindo diabetes, aterosclerose, obesidade
e insuficiência renal aguda. Estudos prévios têm identificado AOPP como um novo
marcador de dano oxidativo a proteínas e uma nova classe de mediadores inflamatórios,
promovendo uma série de efeitos tanto a nível celular quanto a nível sistêmico. Embora
o mecanismo de ação pelo qual os AOPP agem não está totalmente esclarecido, sabe-se
que estes produtos ativam o burst respiratório em fagócitos, incluindo neutrófilos e
monócitos, através da ativação de complexos enzimáticos presentes nestas células.
Além disso, tem sido demonstrado que os AOPP também podem promover efeitos
deletéreis (pró-oxidantes e pró-inflamatórios) a vários tipos celulares, como células
renais e endoteliais, através da ativação de uma cascata de sinalização, sendo em alguns
aspectos desta cascata muito semelhante aos efeitos promovidos pelos produtos finais
de glicação avançada (AGEs). Neste contexto, a avaliação da atividade antioxidante e
antiinflamaória de compostos em modelos in vitro envolvendo a formação de AOPP
pode apresentar especial interesse. Dentre esses compostos, a N-acetilcisteína (NAC) e
a Frutose- 1,6-bisfosfato (FBP) podem ser substâncias promissoras para esta finalidade.
A NAC é um doador de grupo sulfidrila muito semelhante ao aminoácido cisteína e a
FBP é um açúcar bifosforilado e um metabólito intermediário altamente energético da
glicólise. Assim, o principal objetivo deste estudo foi determinar o efeito da FBP e da
NAC, bem como o efeito sinérgico de ambas, sobre a formação de AOPP in vitro. Para
isso, a albumina purificada humana foi incubada com várias concentrações de ácido
hipocloroso (HOCl) (1, 2 e 4 mM) para produzir AOPP in vitro, a qual foi denominada
de albumina-produtos proteicos de oxidação avançada (albumina-AOPP). Neste
contexto, tanto FBP quanto NAC foram capazes de inibir a formação de AOPP de
maneira concentração-dependente, sendo que FBP 20 mg/mL e NAC 1mg/mL foram
responsáveis pela inibição de 64% e 85% respectivamente. Além disso, o efeito
sinérgico promovido pela associação de ambos os compostos foi maisefetivo em inibir a
formação de AOPP quando comparado com o efetio promovido pelos compostos
isoladamente. Portanto, FBP e NAC podem ser candidatos promissores para amenizar
ou neutralizar os efeitos pró-inflamatórios e pró-oxidantes desencadeados pelos AOPP.
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Dietas ricas em gordura, frutose e sacarose: alterações no fígado / Dietas ricas em gordura, frutose e sacarose: alterações no fígado / Diets high in fat, fructose and sucrose: changes in liver / Diets high in fat, fructose and sucrose: changes in liverAlini Schultz Moreira 13 August 2014 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / Hábitos inadequados no estilo de vida, pelo consumo exacerbado de dietas ricas em gorduras e açúcares (frutose e sacarose), correlacionam-se positivamente com o desenvolvimento da obesidade, da resistência à insulina (RI) e da esteatose hepática não alcoólica (NAFLD). O estudo teve como objetivo avaliar a magnitude dos efeitos da administração crônica de dietas ricas em gordura e/ou frutose, e ainda, comparar os efeitos dos açúcares isoladamente (frutose e sacarose) sob as alterações bioquímicas, o perfil inflamatório, as respostas morfofuncionais e as expressões proteicas e gênicas de fatores de transcrição envolvidos na lipogênese, na beta-oxidação, na gliconeogênese e no estresse oxidativo no fígado. Camundongos machos C57BL/6 foram divididos em dois experimentos: 1) Dieta controle/standard chow (SC), dieta high fat (HF 42%), dieta high frutose (HFr 34%) e dieta high fat + high frutose (HFHFr - 42% fat + 34% frutose) por 16 semanas; 2) Dieta controle/standard chow (SC), dieta high frutose (HFru 50%) e dieta high sacarose (HSu 50%) por 15 semanas. Ao final dos experimentos foram observados: 1) Não houve diferença na massa corporal entre os animais HFr e SC, só foi observado ganho de peso nos grupos HF e HFHFr. Houve ainda aumento do colesterol total, dos triglicerídeos plasmáticos e hepáticos e RI nos grupos HF, HFr e HFHFr. No fígado, foi observado NAFLD com aumento na expressão de SREBP-1c e PPAR-γ, e redução de PPAR-α. A gliconeogênese mediada pelo GLUT-2 e PEPCK também foi aumentada nos grupos HF, HFr e HFHFr em relação ao grupo SC. Áreas de necroinflamação também foram observadas nos animais HFr e HFHFr; 2) Não houve diferença na massa corporal entre os grupos SC, HFru e HSu. Porém, houve aumento do colesterol total, dos triglicerídeos plasmáticos e hepáticos, da RI, das adipocinas (IL-6, resistina, MCP-1 e leptina), e redução da adiponectina. No fígado, abundante NAFLD com predominância da expressão proteica e gênica de SREBP-1c, PPAR-γ e redução de PPAR-α; e desequilíbrio antioxidante com redução da SOD, da Catalase e da GRx nos grupos HFru e HSu quando comparados ao SC. Não houve diferença na GPx entre os três grupos. Ainda foi observado aumento na expressão proteica de G6Pase, PEPCK e GLUT-2, envolvidos na gliconeogênese hepática nos grupos HFru e HSu. Áreas de necroinflamação, característico da transição NAFLD-NASH, também foram observados. Os resultados permitem concluir que, independente do aumento da massa corporal, a administração crônica de dietas ricas em frutose e sacarose tem efeitos similares aos observados com o consumo de dieta hiperlipídica. Parece que a RI e a NAFLD sejam os precursores destas alterações. / Habits unsuitable lifestyle, exacerbated by consumption of diets rich in fat and sugars (sucrose and fructose) are positively correlated with the development of obesity, insulin resistance (IR) and nonalcoholic fatty liver disease (NAFLD). The study aimed to evaluate the magnitude of the effects of chronic administration of diets rich in fat and/or fructose, and also compare the effects of sugars alone (fructose and sucrose) in the biochemical changes, the inflammatory profile, and the morphological and functional responses the protein and gene expression of transcription factors involved in lipogenesis, beta-oxidation, gluconeogenesis and oxidative stress in the liver. Male C57BL / 6 mice were divided into two experiments: 1) Diet control/standard chow (SC), high fat diet (HF - 42%), high-fructose diet (HFr - 34%) and high fat + high fructose diet (HFHFr - 42% fat + 34% fructose) for 16 weeks; 2) Diet control/standard chow (SC), high-fructose diet (HFru - 50%) and high sucrose diet (HSu - 50%) for 15 weeks. At the end of the experiments were observed: 1) There was no difference in body mass between HFr and SC groups, only weight gain was observed in the HF group and HFHFr. There was also an increase in total cholesterol, plasma and hepatic triglycerides and IR in HF, HFr, HFHFr groups. In the liver, NAFLD was observed with increased expression of SREBP-1c, PPAR-γ and PPAR-α reduction. The gluconeogenesis mediated by GLUT-2 and PEPCK was also increased in HF, HFr and HFHFr groups compared to SC. Areas of necroinflammation were also observed in HFr and HFHFr; 2) There was no difference in body mass between the SC, HFru and HSu groups. However, there was an increase in total cholesterol, plasma and hepatic triglycerides, IR, adipokines (IL-6, resistin, leptin and MCP-1), and decreased of adiponectin. In the liver, abundant NAFLD with prevalence of protein and gene expression of SREBP-1c, PPAR-γ and PPAR-α reduction; and antioxidant imbalance with reduction of SOD, catalase and GRx in HFru and HSu groups when compared to SC. There was no difference in GPx between the three groups. Further increase in protein expression of G6Pase, PEPCK and GLUT-2, involved in hepatic gluconeogenesis in HFru and HSu groups was noted. Inflammatory infiltrate characteristic of transition NAFLD-NASH were also observed. The results indicate that, regardless of the increase in body mass, chronic administration of diets rich in fructose and sucrose have similar effects to those observed with the consumption of high-fat diet. It seems that IR and NAFLD are the forerunners of these changes.
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