Дисертації з теми "In vitro gastrointestinal assay"
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Schneider, Naira Fernanda Zanchett. "Padronização do ensaio pampa (Parallel Artificial Membrane Permeation Assay) e avaliação in vitro da permeabilidade intestinal e cutânea de compostos de origem natural e sintética." reponame:Repositório Institucional da UFSC, 2012. http://repositorio.ufsc.br/xmlui/handle/123456789/94809.
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O ensaio PAMPA tem demonstrado sua versatilidade desde 1998, sendo utilizado para avaliar a permeabilidade passiva transcellular de fármacos/compostos, e tem ganhado espaço por ser de baixo custo, muito rápido e por auxiliar, particularmente, na elucidação dos mecanismos de transporte, em conjunto com os ensaios que utilizam células Caco-2. Para padronizar este ensaio no Laboratório de Virologia Aplicada da UFSC, dois modelos: o PAMPA TGI, variante Double-Sink e o PAMPA Pele foram selecionados por mimetizar, respectivamente, a absorção de fármacos/compostos através do trato gastrointestinal e da pele,sendo que estas duas vias foram escolhidas pela fácil adesão do paciente aos tratamentos por via oral e tópica. Inicialmente, para demonstrar a funcionalidade dos modelos em estudo, foram selecionados fármacos de alta e baixa permeabilidade, classificados segundo o Sistema de Classificação Biofarmacêutica. Além dos fármacos utilizados para a padronização, alguns cardenolídeos e o composto galato de pentila foram selecionados para testar os modelos padronizados. Para a quantificação das amostras nos compartimentos aceptores e doadores das placas usadas nos experimentos, foram desenvolvidos e validados métodos analíticos por espectrofotometria no UV, segundo critérios preconizados pela ANVISA e ICH. Os resultados obtidos na validação analítica demonstraram que tais métodos foram suficientemente específicos, lineares, precisos e exatos para quantificar as amostras. A partir dos resultados obtidos nos modelos PAMPA TGI, variante Double-Sink e PAMPA Pele, foram calculados os coeficientes de permeabilidade efetiva (Log Pe) para os fármacos/compostos testados, que permearam através das membranas lipídicas usadas e, desta forma, foi possível correlacioná-los com dados da literatura, quando existentes. O galato de pentila apresentou alta permeabilidade nos dois modelos avaliados; já os cardenolídeos apresentaram baixa permeabilidade nos dois modelos, exceto a digitoxigenina, que permeou através da membrana usada no ensaio PAMPA TGI, variante Double-Sink. A integridade das membranas lipídicas usadas nos dois modelos foi avaliada com corantes marcadores de baixa permeabilidade, Azul de Cresil Brilhante (ACB) e Lucifer Yellow (LY), e foi possível demonstrar a integridade e a uniformidade destas membranas, pela baixa passagem do ACB e pela rejeição do LY.
PAMPA assay has demonstrated its versatility since 1998, and it has been used to assess the passive transcellular permeability of drug/compounds, and has gained importance because of its low cost, fast making profile, and also for its particularly help on the elucidation of transport mechanisms together with the assays that make use of caco-2 cells. In order to standardize this assay in the Laboratorio de Virologia Aplicada UFSC, two models: variant Double-Sink PAMPA-GIT and Skin PAMPA were selected by its mimetizing effect on drugs absorption through the gastrointestinal tract and skin, respectively. These two routes were chosen because of easy patient adherence to topical and oral treatment. Initially, to demonstrate the studying models functionality, drugs with high and low permeability were selected, as classified by the Biopharmaceutics Classification System. In addition to the drugs used for standardization, some cardenolide compounds and pentyl gallate were selected to test the standard models. To quantify the samples in compartment acceptors and donors of the plates used in the experiments were developed and analytical methods were validated by UV spectrophotometry, according to the criteria recommended by ICH and ANVISA. The results obtained in the analytical validation showed that these methods were sufficiently specific, linear, precise and accurate to quantify the samples. From the results obtained in PAMPA GIT model, variant Double-Sink PAMPA and skin, the effective permeability coefficients were calculated (log pe) for the drugs / compounds tested that permeated through the lipid membranes used and thus could correlate them with the literature data. The pentyl gallate showed high permeability in the two models evaluated, the cardenolide already had low permeability in the two models, except the digitoxigenin, that permeated through the membrane used in the PAMPA assay TGI, variant Double-Sink. The integrity of the lipid membranes used in both models was assessed with colored markers of low permeability, brilliant cresyl blue (ACB) and Lucifer Yellow (LY), and it was possible to demonstrate the integrity and uniformity of these membranes, the low pass and the ACB rejection of LY.
Harrison, Olivia Jane. "Integrated platform to assay melanoblast development in vitro." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/31164.
Повний текст джерелаWu, Wing-kei Ricky. "Development of an in vitro assay for MMP cleavage /." View the Table of Contents & Abstract, 2005. http://sunzi.lib.hku.hk/hkuto/record/B31494183.
Повний текст джерелаWu, Wing-kei Ricky, and 胡永基. "Development of an in vitro assay for MMP cleavage." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B4501050X.
Повний текст джерелаReader, S. J. "Evaluation of in vitro assay for metabolism-mediated toxicology." Thesis, University of Nottingham, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384371.
Повний текст джерелаSun, Yuxi. "Development of in vitro Chylomicron Assay Using Caco-2 Cells." Digital Commons @ East Tennessee State University, 2013. https://dc.etsu.edu/etd/1781.
Повний текст джерелаSchmid, Oliver. "Untersuchungen zur Genotoxizität von Formaldehyd in vitro und in vivo." [S.l. : s.n.], 2009. http://nbn-resolving.de/urn:nbn:de:bsz:289-vts-66943.
Повний текст джерелаReese, George Edward. "Terahertz Pulsed Imaging of lower gastrointestinal mucosa : an in vitro study." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/26989.
Повний текст джерелаDavies, Catherine Sarah. "In vitro assay of hydroxynaphthoquinones against the liver stages of 'Plasmodium'." Thesis, Imperial College London, 1989. http://hdl.handle.net/10044/1/47401.
Повний текст джерелаAziza, M. A. E. "In vitro studies on drug diffusion through skin membranes and gastrointestinal tract." Thesis, University of Salford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372139.
Повний текст джерелаHolcomb, Steven John. "An oxygen-controlled in vitro model of the gastrointestinal human-microbiome interface." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/115669.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references (pages 86-88).
The gastrointestinal system plays a vital role in the functioning of the human body, processing food into useable energy, controlling homeostasis, and serving as the front line of the immune system. The intestines are aided in their many functions by the gut microbiome, a collection of 100 trillion anaerobic bacteria cells that live inside the GI tract. Although they play an essential part in the organ system, they remain little-represented in in vitro gastrointestinal models because of the difficulty of replicating the anaerobic conditions of the intestines. We constructed an in vitro model capable of growing aerobic epithelial intestinal cells along with anaerobic microbes in the same bioreactor. A device called the apical flow module seals a 12-well transwell and provides an inlet and outlet port into the apical chamber. Media is deoxygenated using nitrogen bubbles before it is pumped using a nitrogen-actuated pneumatic pump block. Microbes are injected into the anaerobic fluid through a rubber septum injection port before the fluid flows into the sealed transwell. Effluent is collected in sterile tubes at a controlled height so as to regulate the apical side pressure. Oxygen is provided to the basolateral human epithelial cells through basolateral circulation achieved using a pneumatic circulation plate. Preliminary testing confirms our ability to control the oxygen in all parts of the system and to grow cocultures of human and bacteria cells. Epithelial cells grown in our bioreactor show signs of behaving more similarly to cells in vivo when exposed to the conditions present in our system, providing researchers with an oxygen-controlled gastrointestinal in vitro model.
by Steven John Holcomb.
S.M.
Shah, Pranjul, Joëlle V. Fritz, Enrico Glaab, Mahesh S. Desai, Kacy Greenhalgh, Audrey Frachet, Magdalena Niegowska, et al. "A microfluidics-based in vitro model of the gastrointestinal human–microbe interface." NATURE PUBLISHING GROUP, 2016. http://hdl.handle.net/10150/614760.
Повний текст джерелаHerron, R. "The in vivo significance of erythrocyte autoantibodies assessed by in vitro methods." Thesis, University of Portsmouth, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372840.
Повний текст джерелаMirza, Mahmooda. "Pathological mutations in thin filament proteins investigated by 'in vitro' motility assay." Thesis, Imperial College London, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.429875.
Повний текст джерелаSmith, Lesley Mary. "Evaluation of an in vitro cytotoxicity assay for specific groups of chemicals." Thesis, University of Nottingham, 1991. http://eprints.nottingham.ac.uk/11910/.
Повний текст джерелаTorihashi, Shigeko, Masaki Kuwahara, and Masaaki Kurahashi. "In Vitro Developmental Model of the Gastrointestinal Tract from Mouse Embryonic Stem Cells." Nagoya University School of Medicine, 2007. http://hdl.handle.net/2237/9187.
Повний текст джерелаGiuliano, Francesco. "Evaluation of the activity and selectivity of non-steroidal anti-inflammatory drugs in vivo, ex vivo and in vitro." Thesis, Queen Mary, University of London, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367598.
Повний текст джерелаGryllos, Ioannis. "Colonisation of the HEp-2 cell in vitro model by Aeromonas caviae : role of flagella and lipopolysaccharide." Thesis, University of Sheffield, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299569.
Повний текст джерелаFilho, Dilson da Silva Pereira. "Desinfecção de endoscópios através da utilização de água ácida eletrolítica (pesquisa prospectiva e in vitro)." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/5/5154/tde-09102014-093609/.
Повний текст джерелаEfficient disinfection is important given the multiplicity of bacterial exposures to equipment used in endoscopy. Glutaraldehyde is used as a disinfectant for endoscopes, but is an irritant and so should be replaced by an alternative. Electrolized cid water (EAW) has bactericidal effect, and an endoscopic washing device using EAW has been developed in Japan. In our study, endoscopic contamination after clinical use was examinated by culture for bacteria, mycobacteria and fungi before and after exposing to glutaraldehyde (20min) and electrolized acid water (7min). The bacterial colonies were identified and counted after 48 hours of incubation at 37oC. Microbial contamination of colonoscopes was detected after 30 endoscopic procedures, but the treatment of the endoscope with EAW eradicated the microbes. The microbicidal activities of EAW was similar to that of glutaraldehyde. These results indicate that EAW is effective disinfectant after mechanical cleaning of colonoscopes, and can, therefore, be used in the endoscopy unit as an alternative to glutaraldehyde
Jin, Wang. "Investigating the reproducibility of in vitro cell biology assays using mathematical models." Thesis, Queensland University of Technology, 2017. https://eprints.qut.edu.au/109790/1/Wang_Jin_Thesis.pdf.
Повний текст джерелаKalezi, Artemis. "Tissue-engineered liver microreactor as an in vitro surrogate assay for gene delivery." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/38981.
Повний текст джерелаIncludes bibliographical references.
The lack of correlation between in vitro and in vivo gene delivery experiments presents a significant obstacle in the progress of gene therapy studies by preventing the extrapolation of successful cell culture results into animals. This phenomenon has also been documented in the specific case of liver where standard hepatocyte culture systems fail to reliably predict the in vivo performance of gene delivery vectors. This is possibly a consequence of the loss of differentiated phenotype that these cells undergo when they are dissociated from their in vivo environment and cultured in vitro. This problem underscores the necessity for better in vitro models that can mimic the physiological environment and responses of in vivo liver tissue. This thesis aimed at developing an alternative in vitro gene delivery assay based on the Tissue-Engineered Liver Microreactor, a culture system designed to facilitate the morphogenesis of three-dimensional tissue-like structures from isolated liver cells under continuous perfusion, maintain cell viability and hepatic functionality for long-term culture periods and enable repeated in situ observation with microscopy. We developed experimental assays to non-invasively detect and quantify gene delivery efficiency in the 3D environment of the microreactor culture based on the application of 2-photon microscopy and spectroscopy.
(cont.) These techniques provide a convenient platform for comparative analysis of different vectors. Our main objective was to compare the gene delivery efficiency of an adenoviral vector (Ad5-CMV-EGFP) in the microreactor system and 2D hepatocyte monolayer culture. Quantitative assays were developed based on Real-Time PCR and RT-PCR to measure the levels of Ad vector uptake and transgene expression. The Ad mass transport in both systems was mathematically modeled to estimate the Ad uptake constant as a basis for comparison of delivery efficiency. This parameter was found to be significantly higher in the microreactor system, suggesting a more efficient mechanism of Ad internalization. Moreover, gene expression was measured in terms of transgene mRNA levels; the ratio of gene expression relative to Ad uptake was estimated as the basis for comparison of vector transcription efficiency. No significant difference was found between the 2 systems. These results provide some evidence that a more physiological culture system can yield different information (potentially more relevant to the in vivo situation) compared to standard in vitro culture.
by Artemis Kalezi.
Ph.D.
Rees, Benjamin James. "Development of the high throughput mammalian PIG-A gene mutation assay in vitro." Thesis, Swansea University, 2015. https://cronfa.swan.ac.uk/Record/cronfa43011.
Повний текст джерелаAZEVEDO, Raquel Alves de. "Development of a new in vitro assay for screening malaria transmission blocking compounds." Master's thesis, Instituto de Higiene e Medicina Tropical, 2016. http://hdl.handle.net/10362/20057.
Повний текст джерелаMalaria is a parasitic disease that affects 214 million people worldwide. One of the greatest struggles of the fight against this parasite resides in its sporogonic stages. Transmission blocking compounds are necessary to prevent transmission of the Plasmodium parasite between humans and mosquitoes. The natural bottleneck created by the transitions from a mature gametocyte in the human host, through fertilization in the mosquito blood meal, to the oocyst in the mosquito, presents a potential target for intervention. In this thesis, we have developed and optimized an in vitro assay for evaluating drug activity in each of the stages of the sporogonic cycle of P. berghei. It includes ookinete and oocyst formation, and oocyst development. A total of ten compounds, atovaquone, azithromycin, chloroquine, cycloheximide, dihydroartemisinin, lumefantrine, halofantrine, pyrimethamine, pyronaridine, and thiostrepton were tested in vitro for their activity on gametocytes and ookinetes and oocysts. The assay was validated in vivo in Anopheles stephensi mosquitoes. We have identified atovaquone, cycloheximide and thiostrepton as three very potent molecules leading to a significant impairment on gametocyte to ookinete conversion and of oocyst development. Overall, this innovative assay is a fast, easy and affordable method for screening large libraries of molecules at a wide range of concentrations for their effect on the development stages of Plasmodium parasites in the mosquito, minimizing the need for an in vivo model. It is urgent to develop and validate high throughput assays allowing for new libraries of compounds to be tested against not only P. berghei, but also P. vivax and also P. falciparum. These assays could be indicative of compounds for preclinical studies to find drugs blocking transmission in the field and in a clinical situation. In the future, new drugs combinations should have not only blood stage activity, but also transmission blocking components.
Yang, Yongliang. "Emergent Leader Cells in Collective Cell Migration in In Vitro Wound Healing Assay." Diss., The University of Arizona, 2014. http://hdl.handle.net/10150/332896.
Повний текст джерелаSundd, Prithu. "MICROPIPETTE CELL ADHESION ASSAY: A NOVEL IN VITROASSAY TO MODEL LEUKOCYTE ADHESION IN THE PULMONARY CAPILLARIES OF THE LUNG." Ohio University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1193868995.
Повний текст джерелаRavindranath, Padma Priya. "PROCESS OPTIMIZATION AND VALIDATION OF AN ASSAY FOR HIGH-THROUGHPUT SCREENING." UKnowledge, 2006. http://uknowledge.uky.edu/gradschool_theses/375.
Повний текст джерелаLuo, Xiaoling. "Development of an in vitro method for the assay of antioxidant activity of melatonin." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0015/MQ56763.pdf.
Повний текст джерелаFässler, Caroline. "Physiological behaviour of resistant starch in the human gastrointestinal tract : evaluation by in vitro models /." Zürich : ETH, 2006. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=16908.
Повний текст джерелаPan, YuanXiang. "Molecular Cloning, In Vitro Expression, and Functional Characterization of an Ovine Gastrointestinal Peptide Transporter (oPepT1)." Diss., Virginia Tech, 2000. http://hdl.handle.net/10919/26296.
Повний текст джерелаPh. D.
Habas, Khaled S. A. "In vitro studies on genotoxicity and gene expression in spermatogenic cells: mechanisms and assay development." Thesis, University of Bradford, 2015. http://hdl.handle.net/10454/14386.
Повний текст джерелаHanna, Joleen. "Validation of an In Vitro Mutagenicity Assay Based on Pulmonary Epithelial Cells from the Transgenic MutaMouse: Intra-Laboratory Variability and Metabolic Competence." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/37312.
Повний текст джерелаKleinerüschkamp, Felix Martin Conrad [Verfasser], and Tobias [Akademischer Betreuer] Görge. "Neues In-vitro-Assay zur Untersuchung der Endothel–Tumorinteraktion im Rahmen der Extravasation : Neues In-vitro Assay zur Untersuchung der Endothel–Tumorinteraktion im Rahmen der Extravasation / Felix Martin Conrad Kleinerüschkamp. Betreuer: Tobias Görge." Münster : Universitäts- und Landesbibliothek der Westfälischen Wilhelms-Universität, 2011. http://d-nb.info/1017896305/34.
Повний текст джерелаHabas, Khaled Said Ali. "In vitro studies on genotoxicity and gene expression in spermatogenic cells : mechanisms and assay development." Thesis, University of Bradford, 2015. http://hdl.handle.net/10454/14386.
Повний текст джерелаMackenzie, Janet Fraser. "Development of a radioligand binding assay for detection of gastrin/CCKâ†#â†Bâ†Eâ†Tâ†Aâ†# receptors in the human gastrointestinal tract." Thesis, University of Glasgow, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318169.
Повний текст джерелаPersson, Malin. "Characterization and optimization of the in vitro motility assay for fundamental studies of myosin II." Doctoral thesis, Linnéuniversitetet, Institutionen för kemi och biomedicin (KOB), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-25241.
Повний текст джерелаLynch, A. M. "Developments of the cytochalasia-b micronucleus/kinetochore assay with Chinese hamster fibroblast cells in vitro." Thesis, Swansea University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637963.
Повний текст джерелаHinkley, Heather Jane. "The in vitro radiosensitivity of fresh lymphocytes from chronic lymphocytic leukaemia using the disc assay." Thesis, University of the West of England, Bristol, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.290438.
Повний текст джерелаRosenbaum, Lara Elise. "Design of an in vitro assay to optimize assembly of nanoparticle-tagged nuclear import complexes." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40471.
Повний текст джерелаIncludes bibliographical references (leaf 20).
Maintaining protein function at the biological-inorganic interface is a critical challenge for bionanotechnology. Specifically, nanoparticle-protein conjugates must be designed to interact with binding partners with biologically-relevant thermodynamics. Towards developing a nanoparticle-tagging system that minimizes interference with normal protein function, here we design and begin development of an assay to assess complex formation between nanoparticle-immobilized proteins and soluble binding partners. Two chaperone proteins, importin-a and importin-3 mediate classical nuclear transport, an essential and highly conserved example of protein complex formation in eukaryotic cells. Together, these two proteins form a chaperone complex that recognizes a nuclear localization signal (NLS), which is a short peptide sequence. Here, we synthesize and purify a fluorescently-labeled importin-a and a positive control for complex formation, which consists of bovine albumin serum (BSA) covalently conjugated to a fluorophore and NLS. Using these two fluorescent molecules, we can perform Forster Resonance Energy Transfer (FRET) experiments to study the kinetics and thermodynamics of these protein interactions. The development of this system will be used in future tests with the NLS-conjugated fluorescent gold nanoparticles.
by Lara Elise Rosenbaum.
S.B.
Palframan, Richard. "A mechanistic study of the in vitro fermentation of xylose containing carbohydrates by the gastrointestinal microflora." Thesis, University of Reading, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.414560.
Повний текст джерелаSANTOS, Lauana Aparecida. "Avaliação da resposta imune in vitro contra antígenos totais de Escherichia coli." Universidade Federal de Alfenas, 2016. https://bdtd.unifal-mg.edu.br:8443/handle/tede/836.
Повний текст джерелаAmong the microorganisms that make it up the intestinal microbiota, stands out Escherichia coli, which has as main ecological niche, the large human intestine. Its importance stands out in being part of the pioneers commensal microorganisms on the colonization of the intestinal mucosa also his pathogenic role causing extra intra and intestinal diseases. The objective of this study was to evaluate the immune response against total antigens of Escherichia coli. The results of this study could aid to understanding systemic immune response to a commensal microorganism that lives in the mucosa. Total E. coli antigens were obtained after lysis with 8M guanidine solution. After dialysis, protein assay was carried out. It was performed electrophoretic characterization of the antigens using polyacrylamide gel electrophoresis and the antigenic profile by Western blotting. We evaluated the presence of total IgG and IgA specific antibodies in 30 human sera. It also assessed the human response of peripheral blood mononuclear cell (PBMC) by MTT metabolization. The results obtained demonstrated that the antigens were composed of various proteins and Western Blotting showed that antigen proteins were recognized by antibodies present in human serum. It was possible to detect the presence of total IgG and IgA antibodies against E. coli antigens by ELISA. In viability assay evaluated by the MTT metabolization by PBMC, it found that cell proliferation occurred at different antigen concentrations, and viability was not less than 70 %. The results suggest that the antigens from E. coli can induce local and systemic responses.
Fundação de Amparo à Pesquisa do Estado de Minas Gerais - FAPEMIG
Chapman, Katherine Emma. "Assessment of the effect of dosing regime and cell culture model on micronucleus induction in in vitro genotoxicity test systems." Thesis, Swansea University, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.678362.
Повний текст джерелаGraça, José Ronaldo Vasconcelos da. "O citrato de sildenafil (viagra®) inibe a motilidade gastrintestinal em ratos acordados e anestesiados e a contratilidade in vitro de tiras isoladas de duodeno de ratos ex vivo." reponame:Repositório Institucional da UFC, 2005. http://www.repositorio.ufc.br/handle/riufc/4036.
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We evaluated the effect of sildenafil citrate (Viagra®) a vasodilator largely used for the treatment of male erectile dysfunction, on the gastrointestinal motility in rats. Experiments were performed on 175 male, Wistar rats, weighing 200-350g. Four groups of study were done: the sildenafil effects on the: i) Gastric emptying (GE) and gastrointestinal (GI) transit and ii) Intestinal transit (IT) of liquid in awake rats; iii) Gastric compliance in anesthetized rats and iv) Contractility of rat duodenal isolated strips. i) In 64 rats fasted for 24h with previous vascular access (right jugular vein and left carotid artery), we studied the effect of an i.v. injection (0.2mL) of sildenafil (4mg/Kg) or vehicle (0.01N HCl) on GE and GI transit of a liquid meal, as well as on arterial pressure (AP) in a separated group of rats. Animals were gavage-fed with 1.5mL of a test meal (0.5mg/mL of phenol red in 5% glucose). After 10, 20 or 30min, animals were sacrificed and submitted to a laparotomy to obstruct the pylorus, cardia and terminal ileus. The gut was removed and then divided into: stomach and consecutive three small intestine segments (40% proximal; 30% medial and 30% terminal). After processing these segments, the dye retention was determined at 560nm. The percentage of dye retention in each segment permitted to evaluate GE and GI transit. Arterial pressure was continuously monitored by a digital acquisition system during 20min before and 30min after sildenafil injection. We observed a significant increase of gastric retention in sildenafil treated rats at 10, 20, or 30min after the test meal (44,2±2,0 vs 53,2±2,1; 25,4±1,3 vs 37,3±1,6; 20,9±2,5 vs 32,5±2,9%, respectively), as well as a significant GI transit delay. Despite of sildenafil inducing hypotension, AP returned to basal levels 10min afterwards. Acid gastic secretion blocking pre-treatment with omeprazol did not modify the sildenafil effect on gastric retention, GI transit or AP. ii) In another group we evaluated the sildenafil (4mg/Kg) or diluente (0.01N HCl, 0.2mL) effects on the IT in awake rats, fasted for 24h. Animals were studied 3d after the insertion of a silastic cannula (0.6cm ID) into the duodenal bulb. We evaluated the progression of a radioactive liquid test meal fed (10MBq of 99mTc – 1mL of saline 0,9%) administered through the inserted cannula into the small intestine. After 20, 30 or 40min, animals were sacrificed by anesthetic overdose. After laparotomy, we removed and divided the gut in: stomach, five congruent and consecutive segments of the small intestine and the large intestine. Radioactivity counting was obtained in a gamma-chamber collimator. Sildenafil promoted an IT delay (p<0.05), indicated by shifting the center of mass to the proximal portions of the TGI (2.8±0.2 vs 3.3±0.1; 3.0±0.2 vs 3.7±0.1 and 3.4±0.1 vs 4.2±0.2) in relation to control group. iii) Gastric compliance study was performed on 39 anesthetized rats after 24h of fasting. Gastric volume (GV) variations were measured by plethysmography while AP was continuously monitored. We have also observed that GV increased (p<0.05) after sildenafil treatment (3mg/Kg - e.v) (3.08±0.18; 3.10±0.17 and 3.09±0.17mL vs 2.91±0.19mL) at 10, 20 and 30min after drug administation, respectively. Basal AP (105.8±2.28mmHg) dropped by the sildenafil injection (59.8±3.2; 64.8±3.7 and 59.3±4.6mmHg-p<0.05) while vehicule (0.01N HCl) did not change either GV or AP. After splanchnotomy or pre-treatments (e.v.) with methylene blue (3mg/Kg-guanilate cyclase blocker), L-NNA (3mg/Kg - NO synthase blocker) or propranolol (2mg/Kg - ß-blocker) prevented GV increase due to sildenafil; while post-treatment with sodium nitroprusside (1mg/Kg - NO donor) raised it. iv) The in vitro contractility studies were performed on isolated duodenal strips obtained from rats (n=28) killed by cervical dislocation. Duodenal strips were suspended longitudinally in a glass chamber (10mL), filled with Tyrode solution (37oC and pH 7.4). After 1h of stabilization under 1g of initial tension, the spontaneous or induced contractility were continuously recorded by a digital acquisition system. Increasing and cummulative doses of sildenafil (0.1 to 300µmol/L) relaxed (9.6µmol/L of EC50) the duodenal strips. This effect was more intense than those displayed by zaprinast or papaverine (PDEs blockers) (91.6 and 78.5µmol/L of EC50, in this order). Sildenafil showed significant antispasmodic and myorelaxant effects on the duodenal contractions induced by acetylcholine or carbamylcholine (IC50 26.7 and 16.2µmol/L, respectively). Pre-treatment with methylene blue, ODQ (guanilato cyclase blocker) or L-NAME (NO synthase blocker) also prevented these sildenafil effects, but D-NAME (an inactive substrate for NO synthase) did not. Myorelaxant sildenafil effect was reverted by L-arginine (substrate for NO synthase) and contrarily it was largely increased by sodium nitroprusside. Forskolin adenylate cyclase activation pre-treatment also increased the myorelaxant effect of sildenafil. In summary, we have observed that sildenafil slowed down the gastrointestinal motility, delaying GE, GI and intestinal transits of a liquid meal in awake rats; Gastric compliance was also increased in anesthetized rats treated with sildenafil. Sildenafil also exhibited both antispasmodic and myorelaxant effects on isolated strips of duodenum of ex vivo rats. Besides central or peripheral sympathetic nervous system activation, sildenafil possibly acts at the gastrointestinal myocite level by activating the NO/GMPc system.
Estudamos o efeito do citrato de sildenafil (Viagra®), vasodilatador largamente utilizado na terapêutica da disfunção erétil, sobre o comportamento motor do trato gastrintestinal (TGI) de ratos Wistar. Para tanto, utilizamos 175 animais machos, pesando entre 200 a 350g, distribuídos nos quatro seguintes grupos de estudo: efeitos do citrato de sildenafil sobre o i) esvaziamento gástrico (EG) e os trânsitos gastrintestinal (GI) e ii) intestinal de líquido em ratos acordados; iii) a complacência gástrica de ratos anestesiados e iv) a contratilidade de tiras isoladas do duodeno de ratos ex vivo. i) Avaliamos, em 64 ratos acordados sob jejum e livre acesso à água por 24h, o efeito da injeção (0,2mL; e.v.) de sildenafil (4mg/Kg) ou veículo (HCl 0,01N) sobre o EG e o trânsito GI de líquido, bem como sobre a pressão arterial (PA). Mediante gavagem, 1,5mL da refeição-teste (vermelho de fenol - 0,5mg/mL em glicose a 5%) foi injetada no estômago. Depois de 10, 20 ou 30min, sacrificamos os animais e, após laparotomia, obstruímos o piloro, o cárdia e o íleo terminal. Removemos e dividimos o TGI em: estômago e segmentos consecutivos do intestino delgado (40% iniciais; 30% mediais e 30% terminais). Após o processamento destas porções viscerais, determinamos as absorbâncias das amostras a 560nm. A retenção fracional de vermelho fenol em cada segmento permitiu o cálculo do EG e trânsito GI. Em um grupo separado de animais, a PA foi monitorada continuamente por meio de um sistema digital de aquisição de dados durante 20min antes e 30min após o tratamento com sildenafil ou diluente. Comparado ao grupo controle, houve aumento significativo da retenção gástrica (44,2±2,0 vs 53,2±2,1; 25,4±1,3 vs 37,3±1,6; 20,9±2,5 vs 32,5±2,9%) nos animais tratados com sildenafil e sacrificados aos 10, 20, ou 30min, respectivamente, bem como retarde significativo no trânsito GI. Embora o sildenafil tenha provocado hipotensão, a PA retoma níveis basais logo após 10min. O pré-tratamento com omeprazol (bloqueador da secreção ácida estomacal) não modificou o efeito do sildenafil sobre os valores de retenção gástrica e intestinal nem nos níveis de PA. ii) Noutros animais (n=44), sob jejum de 24h e dotados previamente (3d) de uma cânula crônica no bulbo duodenal, estudamos o efeito do sildenafil sobre a progressão ao longo do intestino delgado de uma refeição teste (10MBq de Tecnécio ligado a fitato e diluído em 1mL de salina 0,9%). Decorridos 20, 30 ou 40min da injeção (0,2mL e.v.) de sildenafil (4mg/Kg) ou diluente (HCL 0,01N), sacrificamos os animais e, após laparotomia e remoção do TGI, dividimo-o em: estômago, cinco segmentos congruentes e consecutivos de intestino delgado e o intestino grosso. A contagem da radiatividade foi determinada num colimador de gama-câmara. O sildenafil promoveu retarde (p<0,05) do TI, indicado pelos retardes dos centros geométricos da refeição de 2,8± 0,2 vs 3,3± 0,1; 3,0± 0,2 vs 3,7± 0,1 e 3,4± 0,1 vs 4,2± 0,2 em relação ao grupo controle, aos 20, 30 ou 40min. iii) Os estudos de complacência gástrica foram conduzidos em 39 ratos anestesiados, sob jejum de 24h. As variações do volume gástrico (VG), foram medidas por pletismografia, enquanto a PA foi monitorada continuamente por um sistema digital de aquisição de dados. Em relação aos valores basais (2,91±0,19mL) o sildenafil (3mg/Kg – e.v.) aumentou (p<0,05) o VG após 10, 20 e 30min (3,08±0,18; 3,10±0,17 e 3,09±0,17mL). A PA basal (105,8±2,28mmHg) caiu significativamente com o sildenafil (59,8±3,2; 64,8±3,7 e 59,3±4,6mmHg) enquanto o diluente (HCl 0,01N) não modificou seja o VG ou a PA. O pré-tratamento mediante esplancnotomia ou injeção e.v. com azul de metileno (3mg/Kg-bloqueador da guanilato ciclase), L-NNA (3mg/Kg-bloqueador da NO sintetase) ou propranolol (2mg/Kg-ß-bloqueador) preveniram o aumento do VG pelo sildenafil; já o pós-tratamento com nitroprussiato de sódio (1mg/Kg - e.v.) o ampliou significativamente. iv) Avaliamos ainda o efeito do sildenafil sobre a contratilidade de tiras isoladas do duodeno de ratos ex vivo (n=28), sacrificados por deslocamento cervical. Tiras dissecadas do duodeno foram suspensas longitudinalmente em cuba de vidro (10mL), plena de solução de Tyrode (37oC e pH 7,4), e submetidas a uma tensão inicial de 1g. Após 1h de estabilização, a contratilidade espontânea ou induzida das tiras foi registrada continuamente por um sistema digital de aquisição de dados. O sildenafil em doses crescentes e cumulativas (0,1 a 300µmol/L) relaxou (EC50 de 9,6µmol/L) o duodeno, mais até que o zaprinaste ou a papaverina (bloqueadores de FDEs) (EC50 91,6 e 78,5µmol/L, nesta ordem). Observamos ademais que o sildenafil inibiu as contrações induzidas por acetilcolina ou carbacol (IC50 26,7 e 16,2µmol/L, respectivamente). Já o pré-tratamento com azul de metileno, ODQ (bloqueador da guanilato ciclase) ou L-NAME (bloquedor da NO sintetase), mas não o D-NAME (isômero inativo da NO sintetase) preveniram o efeito do sildenafil. O efeito mio-relaxante do sildenafil foi ampliado pela L-arginina (substrato do NO sintetase) ou nitroprussiato de sódio (doador de NO). O pré-tratamento com forskolina (estimulador da adenilato ciclase) também aumentou o efeito mio-relaxante do sildenafil. Em resumo, observamos que o sildenafil diminui a motilidade gastrintestinal, retardando o EG, os trânsitos GI e intestinal de líquido em ratos acordados; aumenta a complacência gástrica em ratos anestesiados além de apresentar efeitos antiespasmódico e mio-relaxante sobre tiras isoladas de duodeno de ratos ex vivo; por estimulação do sistema nervoso simpático e tendo como provável mecanismo de ação ao nível do miócito gastrintestinal a via do NO/GMP cíclico.
ROCCHETTI, GABRIELE. "GLUTEN - FREE FOOD SYSTEM: SCREENING OF POLYPHENOLS AND THEIR BIO ACCESSIBILITY THROUGH IN VITRO GASTROINTESTINAL PROCESSES AND METABOLOMICS - BASED STUDIES." Doctoral thesis, Università Cattolica del Sacro Cuore, 2019. http://hdl.handle.net/10280/57897.
Повний текст джерелаAround 1% of world population is affected by coeliac disease. Coeliac people are constrained to follow a strict gluten free (GF) diet and very often this latter is unbalanced and lacks in many nutrients. In the last years, the exploitation of alternative crops or underutilized species, such as pseudocereals, legumes and pigmented cereal cultivars, is gaining interest because of their amount and profile of bioactive compounds, such as polyphenols. Therefore, considering the actual importance of polyphenols for both the formulation of GF foods and their health-promoting properties, the current PhD thesis was based on: 1) the profiling of polyphenols in GF raw materials (such as non-wheat flours, legumes, pseudocereals and nuts) and their in vitro antioxidant activities; 2) the evaluation of the impact of different heat treatments and microbial fermentations on the phenolic profile of GF raw materials; 3) the investigation of polyphenols in GF foods as inhibitors of digestive enzymes; and 4) the assessment of the fate of polyphenols characterizing GF foods during simulated in vitro gastrointestinal and fermentation processes. Polyphenols were analysed by means of targeted/untargeted metabolomics-based approaches (i.e., high resolution chromatography and mass spectrometry platforms).
Yoo, Ji Yeon. "Development and application of an in vitro physicochemical upper gastrointestinal system (IPUGS) simulating the human digestive processes." Monash University. Faculty of Engineering. Department of Chemical Engineering, 2009. http://arrow.monash.edu.au/hdl/1959.1/75065.
Повний текст джерелаAkhter, Shajeda. "Use of cow faeces to provide micro-organisms for the in vitro digestibility assay of forages." Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240202.
Повний текст джерелаVäyrynen, O. (Otto). "Factors affecting aggressive oral tongue cancer invasion and development of in vitro models for chemoradiotherapy assay." Doctoral thesis, Oulun yliopisto, 2019. http://urn.fi/urn:isbn:9789526222813.
Повний текст джерелаTiivistelmä Makrofageilla on yhteys kielen levyepiteelikarsinooman invaasioon eli syöpäkasvaimen tunkeutumiseen ympäröivään kudokseen. Tutkimuksessamme muokkasimme ihmisen THP-1 leukemiasoluja kemiallisesti tulehdusreittejä aktivoiviksi M1-makrofageiksi, kasvaimeen liittyvien makrofagien kaltaisiksi M2-makrofageiksi sekä imidatsokinoliini-käsitellyiksi R848-makrofageiksi. Tarkoituksenamme oli tutkia makrofagien ja kielisyöpäsolujen vuorovaikutuksia erilaisilla in vitro migraatio- ja invaasiomalleilla. Anti-inflammatoristen, syövän etenemistä edesauttavien TAM-makrofagien kaltaisiksi erilaistetut M2-tyypin makrofagit lisäsivät HSC-3 kielikarsinoomasolujen invaasiota ja migraatiota, kun taas M1-tyypin makrofagien vaikutus oli päinvastainen. Potilaan vaste kemosädehoitoon riippuu syöpäkasvaimen ominaisuuksista, kuten syöpäsolujen aggressiivisuudesta ja syövän levinneisyysasteesta. Tämän vuoksi on tarve uusille menetelmille, joiden avulla voidaan ottaa huomioon potilaan sekä syöpätyypin yksilölliset ominaisuudet hoitoa suunniteltaessa. Testasimme syöpäkasvaimen mikroympäristöä mallintavien, ihmiskudokseen perustuvien menetelmien käyttökelpoisuutta ja luotettavuutta kemosädehoidon vaikutusten arvioimiseen. Testiemme perusteella myoomakudokseen pohjautuvat menetelmät voivat auttaa kemosädehoidon vaikutusten testauksessa. Matriksin metalloproteinaasi (MMP) 9:n on pitkään uskottu olevan yksinomaan syövän etenemistä edesauttava molekyyli. Viimeaikaisissa tutkimuksissa on myös havaittu, että MMP9:llä voi olla syövältä suojaavia vaikutuksia. Tutkimme MMP9:n vaikutusta kielisyöpäsoluihin ja havaitsimme, että MMP9:llä on myös invaasiota hillitseviä vaikutuksia. Lisäksi MMP9 saattaa toimia verisuonten muodostumista estävän arresten-molekyylin syövältä suojaavien mekanismien välittäjänä
Almeida, João Pedro Leão Araújo de. "Validation of a novel human milk oligosaccharide for use in infant formula using gastrointestinal in vitro technologies." Master's thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/21193.
Повний текст джерелаO corpo humano abriga uma comunidade microbiana da qual, parte vive no aparelho digestivo. O cólon é a região com a comunidade bacteriana mais densa, denominada microbiota intestinal. O seu desenvolvimento em bebés pode ser influenciado por um número de fatores, tal como o ambiente intrauterino, tipo de parto e/ou o modo de alimentação. No que diz respeito ao modo de alimentação, o leite materno tem um papel importante na colonização intestinal de bebés através do fornecimento de uma variedade de oligossacáridos. Para bebés que não possam ser amamentados, uma formulação infantil é necessária como substituta e, portanto, deve satisfazer as necessidades nutritivas dos recém-nascidos. A manipulação da microbiota intestinal, recorrendo à adição de probióticos e/ou prebióticos à dieta, tem-se tornado uma prática recorrente. Assim, este estudo teve como objetivo testar um novo oligossacárido do leite humano (NMO), via experiências gastrointestinais in vitro, a fim de proporcionar a melhor formulação possível para substituição do leite humano. Inicialmente, uma experiência de pré-triagem foi realizada para obter informações sobre as potenciais diferenças inter-individuais entre bebés, em resposta à administração de NMO. No global, 7 dos 10 dadores responderam intensamente ao tratamento com NMO, o que resultou numa acidificação do meio. Um efeito bifidogénico foi também observado, com a degradação de NMO ocorrendo através de diferentes cenários de resposta. A escolha do dador 10 foi fundamentada tendo em conta a sua elevada taxa de fermentação e consequente produção de acetato, mas principalmente devido a um intenso efeito bifidogénico, mais especificamente, a um estímulo característico da B. longum subsp. infantis, após administração de NMO. De seguida, um baby M-SHIME® com 5 unidades foi realizado utilizando amostras fecais de um único doador (bebé 10) como inóculo, tornando esta segunda parte do projeto ainda exploratória. Diferentes doses de um "golden standard" (GS) e NMO foram testados. O consumo base-ácido, as concentrações de ácidos gordos de cadeia curta (AGCCs), lactato e amónio e a composição da microbiota foram analisados. Durante o período de tratamento, 3.2 g/L de GS, NMO, ou combinações destes, foram adicionados aos reatores, resultando no aumento dos níveis de consumo de base-ácido e de AGCCs relacionados com a saúde. Um pico no lactato foi observado para as misturas e diminuições dos níveis de marcadores proteolíticos foram também observados. No que diz respeito a mudanças na composição de Bifidobacterium, GS provocou um estímulo de B. longum, enquanto NMO aumentou a abundância de B. longum subsp. infantis, com um efeito dose-resposta claro em ambas as situações. No decorrer do tempo, a administração NMO causou também um aumento dos níveis de Enterobacteriaceae com relação dose-resposta. Das enterobactérias podem também fazer parte alguns agentes patogénicos e, sendo assim, a dosagem de NMO seria recomendada. A dose ótima pode, por conseguinte, ser a dose para a qual existe ainda uma forte estimulação de B. longum subsp. infantis e AGCCs relacionados com a saúde, embora não resultando numa grande expansão de enterobactérias, como, por exemplo, 75% / 25% ou 50% / 50% (GS / NMO).
The human body harbours a microbial community, part of which lives in the gastrointestinal tract. The colon is the region with the densest bacterial community, called gut microbiota. Its development in infants may be influenced by a number of factors, like intra-uterine environment, delivery mode and/or the feeding mode. Regarding the feeding mode, human breast milk plays an important role in early gut colonization of infants. It does so by providing a variety of human milk oligosaccharides. For infants who cannot be breastfed, infant formula is required as a substitute and so, must satisfy the nutritional requirements of infants. Since modulation of gut microbiota resorting to the addition of probiotics and/or prebiotics to the diet is increasingly becoming a recurrent practice, in order to provide infants that do not receive breast-feeding with the best possible alternative formula feeding, this study aimed to test a new human milk oligosaccharide (NMO) via gastrointestinal in vitro experiments. Firstly, a pre-screening experiment was performed to gain information on the potential inter-individual differences among babies in response to NMO administration. Overall, 7 out of the 10 donors responded strongly to the NMO treatment resulting in an acidification of the medium. A bifidogenic effect was also noted, with NMO degradation being found to occur via several different response scenarios. The choice of donor 10 was substantiated based on the strong overall fermentation and corresponding acetate production, but mainly due to a strong bifidogenic effect and thus, most interestingly, a specific stimulation of B. longum subsp. infantis upon NMO administration. Afterwards, a 5 units’ baby M-SHIME® experiment was performed using faecal sample from a single donor (donor 10) as the inoculum, making this second part of the research still exploratory. Different doses of a “golden standard” (GS) and NMO were tested. Base-acid consumption, short chain fatty acids (SCFAs), lactate, ammonium concentrations and microbiota composition were analysed. For the treatment period, 3.2 g/L of GS, NMO or combinations of thereof were supplemented to the vessels resulting in increased base-acid consumption and health-related SCFAs levels. A peak in lactate was observed for the mixtures and minor decreases were also observed on proteolytic markers. With respect to changes in Bifidobacterium composition, it followed that GS stimulated B. longum, while NMO increased the abundance of B. longum subsp. infantis with a clear dose-response effect in both situations. Over time, NMO administration caused an increase of Enterobacteria levels in a dose-related way. Given the fact that Enterobacteria also contain opportunistic pathogens, dosing would be recommended. The optimal NMO dose might therefore be the dose at which there is still a strong stimulation of B. longum ssp. infantis, and health-related SCFAs, although not resulting in a major expansion of Enterobacteria, like for example 75% / 25% or 50% / 50% (GS / NMO).
Rang, Camilla. "Molecular and physiological characteristics of Escherichia coli growth in vitro and in the gastrointestinal tract of mice." Göteborg : [Dept. of General and Marine Microbiology, Göteborg University], 1997. http://catalog.hathitrust.org/api/volumes/oclc/38988157.html.
Повний текст джерелаCarvalho, Mariana Wolff de. "Propriedades e simulação gastrointestinal in vitro de iogurte adicionado de extrato de Stevia Rebaudiana (Bert.) em pó." reponame:Repositório Institucional da UFSC, 2017. https://repositorio.ufsc.br/xmlui/handle/123456789/177863.
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Stevia rebaudiana (Bert.) é uma planta que vem atraindo o interesse da indústria e da comunidade científica nos últimos anos devido aos efeitos do extrato de estévia quanto a sua atividade antioxidante, anti-hiperglicêmica, antimicrobiana e adoçante. Dessa forma, a adição de extrato de S. rebaudiana (Bert.) com o intuito de enriquecer produtos como o iogurte torna-se interessante. Os principais objetivos deste trabalho foram avaliar o comportamento do iogurte incorporado de extrato liofilizado de estévia (FSE) quanto aos aspectos físico-químicos, microbiológicos e ao teor de compostos fenólicos totais (CFT) e atividade antioxidante nos dias 1, 15 e 30 de armazenamento a 4 ± 2 ° C, bem como avaliar a atividade antioxidante através dos métodos FRAP e ABTS e a bioacessibilidade dos compostos fenólicos durante a simulação gastrointestinal in vitro após 30 dias de armazenamento. Foram avaliados iogurtes enriquecidos com 0,25 % e 0,5 % (m/m) de extrato de estévia e um iogurte controle (sem adição de extrato). Tanto a adição quanto a quantidade de FSE adicionado no iogurte contribuíram para o aumento da atividade antioxidante, do teor de CFT, dos parâmetros de cor (a* e b*) e do teor de sólidos totais dos iogurtes. Por outro lado, a acidez, o pH, a sinerese e as contagens de S. thermophilus e L. bulgaricus do produto final não foram significativamente afetadas (p > 0,05). A amostra enriquecida com 0,5 % de FSE apresentou os maiores valores para CFT, ABTS e FRAP. Ao longo do tempo de armazenamento, o teor de de sólidos totais, a sinerese, a cor e o teor de CFT das amostras adicionadas de FSE permaneceram estáveis, enquanto que a atividade antioxidante e o pH diminuíram significativamente. Após a simulação da digestão in vitro, a bioacessibilidade dos compostos fenólicos e a atividade antioxidante dos iogurtes enriquecidos aumentou cerca de 2,5 e 7,5 vezes, respectivamente, em relação às frações não digeridas. Assim, comprova-se que o enriquecimento do iogurte com extrato de estévia aumenta as propriedades antioxidantes e o teor de compostos fenólicos do iogurte, podendo ser uma opção promissora para o desenvolvimento de alimentos funcionais.
Abstract : Stevia rebaudiana (Bert.) is a plant that has been attracting the interest of industry and the scientific community in recent years due to the effects of the stevia extract on its antioxidant , antihyperglycemic, antihypertensive, antimicrobial activity and sweetener. In this way, it became interesting to add extracts such as S. rebaudiana (Bert.) in order to enrich products such as yogurt. The main objectives of this work were to evaluate the behavior of the incorporated yogurt of freeze-dried stevia extract (FSE) regarding the physicochemical, microbiological and total phenolic compounds (CFT) and antioxidant activity on days 1,15 and 30 of storage at 4 ± 2 °C, in addition to evaluating the antioxidant activity through the FRAP and ABTS methods and the bioaccessibility of the phenolics during in vitro gastrointestinal simulation at the end of the shelf life (day 30). The yogurts enriched with 0,25 and 0,5 % (w / w) of stevia extract and the control sample (without extract) were evaluated. The incorporation of FSE and the percentage of addition contributed to increase antioxidant activity, CFT, color parameters (increased values for a* and b* and decreased value for L *) and total solids; while the acidity, pH, syneresis and counts of S. thermophilus and L. bulgaricus of the final product were not significantly affected (p> 0,05). The sample enriched with 0.5 % FSE presented the highest values for CFT, ABTS and FRAP. Throughout the storage time, the parameters of total solids, syneresis, color and CFT of the samples added of FSE remained stable, whereas the antioxidant activity and pH decreased significantly. After in vitro digestion simulation, the bioaccessibility of the CFT and the antioxidant activity of the enriched yogurts increased by 2,5 and 7,5 times, respectively, in relation to the undigested fractions. Thus, it is proven that the enrichment of yogurt with stevia extract actually increases the antioxidant properties and the amount of phenolic compounds of the yogurt, being to be a promising option for the development of functional foods.
Reynolds, Elizabeth A. "Studies on the evolution of the ethylene forming enzyme : 1-aminocyclopropane-1-carboxylate (ACC) oxidase." Thesis, University of Reading, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343225.
Повний текст джерела