958 resultados para CYTOKINE-INDUCED APOPTOSIS
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We report here the protein expression of TRPV1 receptor in axotomized rat retinas and its possible participation in mechanisms involved in retinal ganglion cell (RGC) death. Adult rats were subjected to unilateral, intraorbital axotomy of the optic nerve, and the retinal tissue was removed for further processing. TRPV1 total protein expression decreased progressively after optic nerve transection, reaching 66.2% of control values 21 days after axotomy. The number of cells labeled for TRPV1 in the remnant GCL decreased after 21 days post-lesion (to 63%). Fluoro-jade B staining demonstrated that the activation of TRPV1 in acutely-lesioned eyes elicited more intense neuronal degeneration in the GCL and in the inner nuclear layer than in sham-operated retinas. A single intraocular injection of capsazepine (100 mu M), a TRPV1 antagonist, 5 days after optic nerve lesion, decreased the number of GFAP-expressing Muller cells (72.5% of control values) and also decreased protein nitration in the retinal vitreal margin (75.7% of control values), but did not affect lipid peroxidation. Furthermore, retinal explants were treated with capsaicin (100 mu M), and remarkable protein nitration was then present, which was reduced by blockers of the constitutive and inducible nitric oxide synthases (7-NI and aminoguanidine, respectively). TRPV1 activation also increased GFAP expression, which was reverted by both TRPV1 antagonism with capsazepine and by 7-NI and aminoguanidine. Given that Muller cells do not express TRPV1, we suppose that the increased GFAP expression in these cells might be elicited by TRPV1 activation and by its indirect effect upon nitric oxide overproduction and peroxynitrite formation. We incubated Fluorogold pre-labeled retinal explants in the presence of capsazepine (1 mu M) during 48 h. The numbers of surviving RGCs stained with fluorogold and the numbers of apoptotic cells in the GCL detected with TUNEL were similar in lesioned and control retinas. We conclude that TRPV1 receptor expression decreased after optic nerve injury due to death of TRPV1-containing cells. Furthermore, these data indicate that TRPV1 might be involved in intrinsic protein nitration and Muller cell reaction observed after optic nerve injury. (C) 2010 Elsevier Ltd. All rights reserved.
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Exposure to a high glucose medium or diabetes has been found to protect the heart against ischaemia. The activation of antiapoptotic and proliferative factors seems to be involved in this cardioprotection. This study was designed to evaluate the role of hyperglycaemia in cardiac function, programmed cell survival, and cell death in diabetic rats after myocardial infarction (MI). Male Wistar rats were divided into four groups (n = 8): control (C), diabetic (D), myocardial infarcted (MI), and diabetic myocardial infarcted (DI). The following measures were assessed in the left ventricle: size of MI, systolic and diastolic function by echocardiography, cytokines by ELISA (TNF-alpha, IL-1 beta, IL-6, and IL-10), gene expression by real-time PCR (Bax, Fas, p53, Bcl-2, HIF1-alpha, VEGF, and IL8r), caspase-3 activity by spectrofluorometric assay, glucose transporter type 1 and 4 (GLUT-1 and GLUT-4) protein expression by western blotting, and capillary density and fibrosis by histological analysis. Systolic function was improved by hyperglycaemia in the DI group, and this was accompanied by no improvement in diastolic dysfunction, a reduction of 36% in MI size, reduced proinflammatory cytokines, apoptosis activation, and an increase in cell survival factors (HIF1-alpha, VEGFa and IL8r) assessed 15 days post-MI. Moreover, hyperglycaemia resulted in angiogenesis (increased capillary density) before and after MI, accompanied by a reduction in fibrosis. Together, these results suggest that greater plasticity and cellular resistance to ischaemic injury result from chronic diabetic hyperglycaemia in rat hearts.
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The effect of an adventure race (Ecomotion Pr), which lasted for 4-5 days, on neutrophil and lymphocyte death from elite athletes was investigated. Blood was collected from 11 athletes at rest and after the adventure race. The following parameters of cell death were measured in neutrophils and lymphocytes: cell membrane integrity, DNA fragmentation, mitochondrial transmembrane depolarization and reactive oxygen species (ROS) production. Phagocytosis capacity was also evaluated in neutrophils. The adventure race raised the proportion of cells with the loss of membrane integrity; lymphocytes by 14% and neutrophils by 16.4%. The proportion of lymphocytes with DNA fragmentation (2.9-fold) and mitochondrial transmembrane depolarization (1.5-fold) increased. However, these parameters did not change in neutrophils. ROS production remained unchanged in lymphocytes, whereas an increase by 2.2-fold was found in neutrophils due to the race. Despite these changes, the phagocytosis capacity did not change in neutrophils after the race. In conclusion, the Ecomotion Pr race-induced neutrophil death by necrosis (as indicated by the loss of membrane integrity) and led to lymphocyte death by apoptosis (as indicated by increase DNA fragmentation and depolarization of mitochondrial membrane).
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Short chain fatty acids (SCFAs) are fermentation products of anaerobic bacteria. More than just being an important energy source for intestinal epithelial cells, these compounds are modulators of leukocyte function and potential targets for the development of new drugs. The aim of this study was to evaluate the effects of SCFAs (acetate, propionate and butyrate) on production of nitric oxide (NO) and proinflammatory cytokines [tumor necrosis factor alpha (TNF-alpha) and cytokine-induced neutrophil chemoattractant-2 (CINC-2 alpha beta)] by rat neutrophils. The involvement of nuclear factor kappa B (NF-kappa B) and histone deacetylase (HDAC) was examined. The effect of butyrate was also investigated in vivo after oral administration of tributyrin (a pro-drug of butyrate). Propionate and butyrate diminished TNF-alpha, CINC-2 alpha beta and NO production by LPS-stimulated neutrophils. We also observed that these fatty acids inhibit HDAC activity and NF-kappa B activation, which might be involved in the attenuation of the LPS response. Products of cyclooxygenase and 5-lipoxygenase are not involved in the effects of SCFAs as indicated by the results obtained with the inhibitors of these enzymes. The recruitment of neutrophils to the peritonium after intraperitoneal administration of a glycogen solution (1%) and the ex vivo production of cytokines and NO by neutrophils were attenuated in rats that previously received tributyrin. These results argue that this triglyceride may be effective in the treatment of inflammatory conditions. Crown Copyright (C) 2011 Published by Elsevier Inc. All rights reserved.
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Lipid emulsion (LE) containing medium/omega-6 long chain triglyceride-based emulsion (MCT/omega-6 LCT LE) has been recommended in the place of omega-6 LCT-based emulsion to prevent impairment of immune function. The impact of MCT/omega-6 LCT LE on lymphocyte and neutrophil death and expression of genes related to inflammation was investigated. Seven volunteers were recruited and infusion of MCT/omega-6 LCT LE was performed for 6 h. Four volunteers received saline and no change was found. Blood samples were collected before, immediately afterwards and 18 h after LE infusion. Lymphocytes and neutrophils were studied immediately after isolation and after 24 and 48 h in culture. The following determinations were carried out: plasma-free fatty acids, triacylglycerol and cholesterol concentrations, plasma fatty acid composition, neutral lipid accumulation in lymphocytes and neutrophils, signs of lymphocyte and neutrophil death and lymphocyte expression of genes related to inflammation. MCT/omega-6 LCT LE induced lymphocyte and neutrophil death. The mechanism for MCT/omega-6 LCT LE-dependent induction of leucocyte death may involve changes in neutral lipid content and modulation of expression of genes related to cell death, proteolysis, cell signalling, inflammatory response, oxidative stress and transcription.
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SCFAs (short-chain fatty acids) are produced by anaerobic bacterial fermentation. Increased concentrations of these fatty acids are observed in inflammatory conditions, such as periodontal disease, and at sites of anaerobic infection. In the present study, the effect of the SCFAs acetate, propionate and butyrate on neutrophil chemotaxis and migration was investigated. Experiments were carried out in rats and in vitro. The following parameters were measured: rolling, adherence, expression of adhesion molecules in neutrophils (L-selectin and beta 2 integrin), transmigration, air pouch influx of neutrophils and production of cytokines [CINC-2 alpha beta (cytokine-induced neutrophil chemoattractant-2 alpha beta), IL-1 beta (interleukin-1 beta), MIP-1 alpha (macrophage inflammatory protein-1 alpha) and TNF-alpha (tumour necrosis factor-alpha)]. SCFAs induced in vivo neutrophil migration and increased the release of CINC-2 alpha beta into the air pouch. These fatty acids increased the number of rolling and adhered cells as evaluated by intravital microscopy. SCFA treatment increased L-selectin expression on the neutrophil surface and L-selectin mRNA levels, but had no effect on the expression of beta 2 integrin. Propionate and butyrate also increased in vitro transmigration of neutrophils. These results indicate that SCFAs produced by anaerobic bacteria raise neutrophil migration through increased L-selectin expression on neutrophils and CINC-2 alpha beta release.
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LEVADA-PIRES, A. C., M. F. CURY-BOAVENTURA, R. GORJAO, S. M. HIRABARA. E. F. PUGGINA, I. L. PELLEGRINOTTI, L. A. DOMINGUES FILHO, R. CURI, and T. C. PITHON-CURI. Induction of Lymphocyte Death by Short- and Long-Duration Triathlon Competitions. Med. Sci. Sporty Exerc., Vol. 4 1, No. 10, pp. 1896-1901, 2009. Purpose: The effect of triathlon competitions on death of lymphocytes from elite athletes was investigated. Material and Methods: Blood was collected from sedentary volunteers and triathletes at rest and after a short-duration triathlon (SDT) and after a long-duration triathlon (LDT-half Ironman) competitions. Results: The athletes had lowered lymphocyte proliferation capacity compared with sedentary volunteers either at rest or after the competitions. There was no difference in the parameters associated with lymphocyte death when sedentary volunteers were compared with triathletes at rest. Lymphocytes from triathletes after SDT competition showed an increase in DNA fragmentation, phosphatidylserine externalization, and mitochondrial transmembrane depolarization and did not alter membrane integrity when compared with cells from athletes at rest. In contrast, the LDT competition raised the proportion of lymphocytes with loss of membrane integrity when compared with cells from athletes at rest and did not change the apoptotic parameters. The LDT competition induced an increase of reactive oxygen species (ROS) production by lymphocytes compared with triathletes at rest. The SDT competition did not alter ROS production by lymphocytes when compared with cells from triathletes at rest. ROS production by lymphocytes after LDT competition was 60% higher than in SDT. Conclusions: Evidence is presented herein that an LDT competition caused lymphocyte death by necrosis, whereas an SDT induced lymphocyte apoptosis. The mechanism for lymphocyte death induced by the triathlon competitions may involve an increase in ROS production at different extents.
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CD95 (Fas/Apo-1)-mediated apoptosis was shown to occur through two distinct pathways. One involves a direct activation of caspase-3 by large amounts of caspase-8 generated at the DISC (Type I cells). The other is related to the cleavage of Bid by low concentration of caspase-8, leading to the release of cytochrome c from mitochondria and the activation of caspase-3 by the cytochrome c/APAF-1/caspase-9 apoptosome (Type 11 cells). It is also known that the protein synthesis inhibitor cycloheximide (CHX) sensitizes Type I cells to CD95-mediated apoptosis, but it remains contradictory whether this effect also occurs in Type II cells. Here, we show that sub-lethal doses of CHX render both Type I and Type II cells sensitive to the apoptogenic effect of anti-CD95 antibodies but not to chemotherapeutic drugs. Moreover, Bcl-2-positive Type II cells become strongly sensitive to CD95-mediated apoptosis by the addition of CHX to the cell culture. This is not the result of a restraint of the anti-apoptotic effect of Bcl-2 at the mitochondrial level since CHX-treated Type II cells still retain their resistance to chemotherapeutic drugs. Therefore, CHX treatment is granting the CD95-mediated pathway the ability to bypass the mitochondria requirement to apoptosis, much alike to what is observed in Type I cells. (c) 2007 Elsevier Inc. All rights reserved.
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Snake venom metalloproteinases (SVMPs) have been extensively studied and their effects associated with the local bleeding observed in human accidents by viper snakes. Representatives of P-I and P-III classes of SVMPs similarly hydrolyze extracellular matrix proteins or coagulation factors while only P-III SVMPs induce significant hemorrhage in experimental models. In this work, the effects of P-I and P-III SVMPs on plasma proteins and cultures of muscle and endothelial cells were compared in order to enlighten the mechanisms involved in venom-induced hemorrhage. To reach this comparison, BnP1 was isolated from B. neuwiedi venom and used as a weakly hemorrhagic P-I SVMPs and jararhagin was used as a model of potently hemorrhagic P-III SVMP. BnP1 was isolated by size exclusion and anion-exchange chromatographies, showing apparent molecular mass of approximately 24kDa and sequence similarity with other members of SVMPs, which allowed its classification as a group P-I SVMP. The comparison of local effects induced by SVMPs showed that BnP1 was devoid of significant myotoxic and hemorrhagic activities and jararhagin presented only hemorrhagic activity. BnP1 and jararhagin were able to hydrolyze fibrinogen and fibrin, although the latter displayed higher activity in both systems. Using HUVEC primary cultures, we observed that BnP1 induced cell detachment and a decrease in the number of viable endothelial cells in levels comparable to those observed by treatment with jararhagin. Moreover, both BnP1 and jararhagin induced apoptosis in HUVECs while only a small increase in LDH supernatant levels was observed after treatment with jararhagin, suggesting that the major mechanism involved in endothelial cell death is apoptosis. Jararhagin and BnP1 induced little effects on C2C12 muscle cell cultures, characterized by a partial detachment 24h after treatment and a mild necrotic effect as evidenced by a small increase in the supernatants LDH levels. Taken together, our data show that P-I and P-III SVMPs presented comparable effects except for the hemorrhagic activity, suggesting that hydrolysis of coagulation factors or damage to endothelial cells are not sufficient for induction of local bleeding. (C) 2007 Elsevier Ltd. All rights reserved.
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Background: Allergic lung inflammation is impaired in diabetic rats and is restored by insulin treatment. In the present study we investigated the effect of insulin on the signaling pathways triggered by allergic inflammation in the lung and the release of selected mediators. Methods: Diabetic male Wistar rats (alloxan, 42 mg/kg, i.v., 10 days) and matching controls were sensitized by s.c. injections of ovalbumin (OA) in aluminium hydroxide, 14 days before OA (1 mg/0.4 ml) or saline intratracheal challenge. A group of diabetic rats were treated with neutral protamine Hagedorn insulin (NPH, 4 IU, s.c.), 2 h before the OA challenge. Six hours after the challenge, bronchoalveolar lavage (BAL) was performed for mediator release and lung tissue was homogenized for Western blotting analysis of signaling pathways. Results: Relative to non-diabetic rats, the diabetic rats exhibited a significant reduction in OA-induced phosphorylation of the extracellular signal-regulated kinase (ERK, 59%), p38 (53%), protein kinase B (Akt, 46%), protein kinase C (PKC)-alpha (63%) and PKC-delta (38%) in lung homogenates following the antigen challenge. Activation of the NF-kappa B p65 subunit and phosphorylation of I kappa B alpha were almost suppressed in diabetic rats. Reduced expression of inducible nitric oxide synthase (iNOS, 32%) and cyclooxygenase-2 (COX-2, 46%) in the lung homogenates was also observed. The BAL concentration of prostaglandin (PG)-E(2), nitric oxide (NO) and interleukin (IL)-6 was reduced in diabetic rats (74%, 44% and 65%, respectively), whereas the cytokine-induced neutrophil chemoattractant (CINC)-2 concentration was not different from the control animals. Treatment of diabetic rats with insulin completely or partially restored all of these parameters. This protocol of insulin treatment only partially reduced the blood glucose levels. Conclusion: The data presented show that insulin regulates MAPK, PI3K, PKC and NF-kappa B pathways, the expression of the inducible enzymes iNOS and COX-2, and the levels of NO, PGE(2) and IL-6 in the early phase of allergic lung inflammation in diabetic rats. It is suggested that insulin is required for optimal transduction of the intracellular signals that follow allergic stimulation. Copyright (C) 2010 S. Karger AG, Basel
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Accumulating evidence indicates that post-translational protein modifications by nitric oxide and its derived species are critical effectors of redox signaling in cells. These protein modifications are most likely controlled by intracellular reductants. Among them, the importance of the 12 kDa dithiol protein thioredoxin-1 (TRX-1) has been increasingly recognized. However, the effects of TRX-1 in cells exposed to exogenous nitrosothiols remain little understood. We investigated the levels of intracellular nitrosothiols and survival signaling in HeLa cells over-expressing TRX-1 and exposed to S-nitrosoglutahione (GSNO). A role for TRX-1 expression on GSNO catabolism and cell viability was demonstrated by the concentration-dependent effects of GSNO on decreasing TRX-1 expression, activation of capase-3, and increasing cell death. The over-expressaion of TRX-1 in HeLa cells partially attenuated caspase-3 activation and enhanced cell viability upon GSNO treatment. This was correlated with reduction of intracellular levels of nitrosothiols and increasing levels of nitrite and nitrotyrosine. The involvement of ERK, p38 and JNK pathways were investigated in parental cells treated with GSNO. Activation of ERK1/2 MAP kinases was shown to be critical for survival signaling. lit cells over-expressing TRX-1, basal phosphorylation levels of ERK1/2 MAP kinases were higher and further increased after GSNO treatment. These results indicate that the enhanced cell viability promoted by TRX-1 correlates with its capacity to regulate the levels of intracellular nitiosothiols and to up-regulate the survival signaling pathway mediated by the ERK1/2 MAP kinases.
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Objectives The antitumoural properties of grandisin, a tetrahydrofuran neolignan from Piper solmsianum, were investigated by in-vitro and in-vivo assays using the Ehrlich ascites tumoural (EAT) model. Methods Viability of the tumour cells was evaluated by Trypan blue exclusion and MTT methods, after incubation with grandisin (0.017-2.3 mu M). The effects of grandisin on the activity of caspase-3, -6, -8, and -9 were also investigated using colorimetric protease kits. In-vivo studies were performed in EAT-bearing mice treated intraperitoneally with 2.5, 5 or 10 mg/kg grandisin for 10 days. Key findings Grandisin inhibited the growth of EAT cells, by both methods, with IC50 values less than 0.25 mu M. The results showed that the activity of all the caspases studied increased in grandisin-treated cells, when compared with control, non-treated cells. Administering grandisin to EAT-bearing mice increased survival of the animals, in a dose-dependent manner. Simultaneously, we detected a 66.35% reduction of intraperitoneal tumour cell burden in the animals treated with 10 mg/kg grandisin. Additionally, in these animals, the marked increase of vascular endothelial growth factor (VEGF) levels, induced by EAT development, was decreased with treatment with grandisin, resulting in a reduction of 32.1% of VEGF levels in the peritoneal washing supernatant, when compared with the control. Conclusions The results demonstrated that grandisin induced in-vitro cytotoxicity and antiangiogenic effects in mice while it acted against tumour evolution, prolonging host survival.
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The corn cob is an agricultural by-product still little used, this in part due to the low knowledge of the biotechnological potential of their molecules. Xylan from corn cobs (XSM) is a polysaccharide present in greater quantity in the structure of plant and its biotechnology potential is little known. This study aimed to the extraction, chemical characterization and evaluation of biological activities of xylan from corn cobs. To this end, corncobs were cleaned, cut, dried and crushed, resulting in flour. This was subjected to a methodology that combines the use of alkaline conditions with waves of ultrasound. After methanol precipitation, centrifugation and drying was obtained a yield of 40% (g/g flour). Chemical analysis indicated a high percentage of polysaccharides in the sample (60%) and low contamination by protein (0.4%) and phenolic compounds (> 0.01%). Analysis of monosaccharide composition indicated the presence of xylose:glucose:arabinose:galactose:mannose:glucuronic acid in a molar ratio 50:20:15:10:2.5:2.5. The presence of xylan in the sample was confirmed by nuclear magnetic resonance (¹H and ¹³C) and infrared spectroscopy (IR). Tests were conducted to evaluate the antioxidant potential of XSM. This showed a total antioxidant capacity of 48.45 EAA/g sample. However, did not show scavenging activity of superoxide and hydroxyl radical and also reducing power. But, showing a high capacity chelating iron ions with 70% with about 2 mg/mL. The ability to XSM to influence cell proliferation in culture was also evaluated. This polymer did not influence the proliferation of normal fibroblast cells (3T3), however, decreased the rate of proliferation of tumor cells (HeLa) in a dose-dependent, reaching an inhibition of about 50% with a concentration around 2 mg/mL. Analyzing proteins related to cell death, by immunoblotting, XSM increases the amount of Bax, Bcl-2 decrease, increase cytochrome c and AIF, and reduce pro-caspase-3, indicating the induction of cell death induced apoptosis dependent and independent of caspase. XSM did not show anticoagulant activity in the PT test. However, the test of activated partial thromboplastin time (aPTT), XSM increased clotting time at about 5 times with 600 μg of sample compared with the negative control. The presence of sulfate on the XSM was discarded by agarose gel electrophoresis and IR. After carboxyl-reduction of XSM the anticoagulant activity decreased dramatically. The data of this study demonstrate that XSM has potential as antioxidant, antiproliferative and anticoagulant compound. Future studies to characterize these activities of XSM will help to increase knowledge about this molecule extracted from corn and allow their use in functional foods, pharmaceuticals and chemical industries.
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Seaweeds are organisms known to exhibit a variety of biomolecules with pharmacological properties. The coast of Rio Grande do Norte has over 100 species of seaweeds, most of them not yet explored for their pharmacological potential. Sugars and phenolic compounds are the most studied of these being assigned a range of biological properties, such as anticoagulant , antiinflammatory, antitumor and antioxidant activities. In this work, we obtained methanolic extracts from thirteen seaweeds of the coast of Rio Grande do Norte (Dictyota cervicornis; Dictiopterys delicatula; Dictyota menstruallis; D. mertensis; Sargassum filipendula; Spatoglossum schröederi; Acanthophora specifera; Botryocladia occidentalis; Caulerpa cupresoides; C. racemosa; C. prolifera; C. sertularioides e Codium isthmocladum). They were evaluated as anticoagulant and antioxidant drugs, as well as antiproliferative drugs against the tumor cell line HeLa. None of the methanolic extracts showed anticoagulant activity, but when they were evaluated as antioxidant drugs all of extracts showed antioxidant activity in all tests performed (total antioxidant capacity, sequestration of superoxide and hydroxyl radicals, ferric chelation and reductase activity), especially the algae D. mentrualis, D. cilliolata and C. prolifera, who had the greatest potential to donate electrons.In addition, the ability of iron ions chelation appears as the main antioxidant mechanism of the methanolic extracts of these seaweeds mainly for the extract of the C. racemosa seaweed, which reached almost 100% activity. In the MTT assay, all extracts showed inhibitory activity at different levels againts HeLa cells. Moreover, D. cilliolata (MEDC) and D. menstrualis (MEDM) extracts showed specific activity to this cell line, not inhibiting the viability of 3T3 normal cell line, so they were chosen for detailing the antiproliferative mechanism of action. Using flow cytometry, fluorescence microscopy and in vitro assays we demonstrated that MEDC and MEDM induced apoptosis in HeLa cells by activation of caspases 3 and 9 and yet, MEDC induces cell cycle arrest in S phase. Together, these results showed that the methanolic extracts of brown seaweed D. menstrualis and D. cilliolata may contain agents with potential use in combatting cells from human uterine adenocarcinoma. This study also points to the need for more in-depth research on phytochemical and biological context to enable the purification of biologically active products of these extracts
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)