Teses / dissertações sobre o tema "Hevea brasiliensis latex"
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CAURET, LAUREN. "Nouveaux stimulants pour la production de latex par l'hevea brasiliensis". Le Mans, 1995. http://www.theses.fr/1995LEMA1017.
Texto completo da fonteIntapun, Jutharat. "Study of the effects of biological maturation of coagula of hevea brasiliensis latex on dry rubber properties". Montpellier SupAgro, 2009. http://www.theses.fr/2009NSAM0036.
Texto completo da fonteL'objectif de ce travail était d'étudier le phénomène de maturation des coagula de latex d'Hevea brasiliensis. La stratégie expérimentale a consisté dans un premier temps à caractériser les conditions de maturations régnant sur un site industriel (température,humidité relative, teneur en oxygène de l'air), puis de reproduire ces conditions de maturation à l'échelle du laboratoire dans le but de pouvoir, dans une troisième phase, étudier l'effet de paramètres clés tels que la population microbienne ou l'activité de diverses enzymes sur les propriétés du caoutchouc naturel obtenu à partir de ces coagula. Les conditions de maturation des coagula de latex empilés sur un site industriel ont été caractérisées. Ceci a nécessité la mise au point d'un matériel expérimental spécifique permettant des mesures fiables et répétables. Nous avons montré que la température et l'humidité relative de l'air au sein du tas augmentent avec la profondeur, alors que la teneur en oxygène diminue jusqu'à des conditions d'anaérobiose. Après 24 jours de maturation dans ces conditions, les propriétés des coagula (pH) et du caoutchouc obtenu (P0, PRI, masse moléculaire moyenne) dépendent de la position des coagula au sein de la pile. L'étude de la maturation des coagula dans des conditions de laboratoire contrôlées a nécessité des développements méthodologiques et techniques aboutissant à la mise en place et à l'optimisation d'un dispositif de maturation contrôlée associé à un procédé miniaturisé de production de caoutchouc sec comprenant une étape de crêpage et un séchage au four. Ce dispositif a été confronté au système réel en vérifiant que la réduction d'échelle n'introduisait pas de biais dans les propriétés des produits étudiés. Le dispositif de maturation contrôlée est constitué de 6 unités pouvant fonctionner en parallèle, chacune d'entre elle pouvant contenir jusqu’à 18 échantillons. Les unités sont contrôlées en humidité relative (10%-90%), température (35Ê C - 45Ê C) et teneur en oxygène (0-21%). Sur la base des mesures réalisées sur site industriel, les études on été réalisées à 40Ê CØ+1Ê C et 90%Ø+10% d'humidité relative dans le dispositif de maturation. Nous avons ensuite démontré le rôle des microorganismes dans la maturation des coagula de latex et leur impact sur les propriétés du caoutchouc naturel sec en comparant les propriétés physiques et structurales, avant et après maturation, d'échantillons de caoutchouc issus de coagula inoculés avec des quantités variables de microorganismes provenant d'un coagulum industriel. Cette étude a mis en évidence un effet-dose des microorganismes sur ces propriétés. Les microorganismes contenus dans l'inoculum comprenaient des levures et des bactéries gram positives et gram négatives, dont des bactéries lactiques. Quinze des seize souches isolées produisaient des enzymes hydrolytiques, notamment à activité lipase, phospholipase et protéase, qui pourraient participer à la dégradation de lipides et protéines au sein du latex et des coagula. L'addition de lipase pure à des coagula dans lesquels le développement des microorganismes était inhibé a provoqué la libération d'acides gras sans toutefois modifier les propriétés du caoutchouc après 6 jours de maturation. Par contre, l'addition de papaÉine a provoqué une amélioration de la valeur de la viscosité initiale (P0) des échantillons directement liée à la quantité d'enzyme ajoutée. L'activité de cette protéase a également entraîné une augmentation de la résistance à la thermooxydation (PRI) du caoutchouc. Les méthodologies et outils développés au cours de se travail devraient permettre le développement de futures recherches visant à comprendre le rôle des microorganismes et des enzymes dans la variabilité de la qualité du caoutchouc naturel
Gomes, Willian Pereira. "Prevulcanização do látex natural extraído da "hancornia speciosa gomes" (Mangabeira) e da "hevea brasiliensis" (seringueira) /". Ilha Solteira, 2013. http://hdl.handle.net/11449/136022.
Texto completo da fonteBanca: Rosangela da Silva de Lauretiz
Banca: Rogério Manoel Biagi Moreno
Resumo: A borracha natural é um dos polímeros mais consumidos mundialmente, onde seu principal mercado é o setor pneumático com cerca de três quartos do consumo total. A seringueira é a mais importante produtora de borracha natural, sendo responsável por cerca de 99% da produção mundial A mangabeira é também uma arvore lactescente produzida quase em sua totalidade de forma extrativista e visada somente para a produção do seu fruto, a mangaba. Embora já ter sido utilizada comercialmente em períodos emergenciais, hoje a borracha natural provinda da mangabeira não tem qualquer utilização tecnológica, pois é considerada uma borracha de qualidade inferior. Neste trabalho foram produzidos filmes de borracha prevulcanizada com o látex de seringueira, de mangabeira e também com a mistura (m/m) do látex de mangabeira no látex de seringueira, nas proporções de 95/5, 90/10, 80/20, 70/30 e 60/40. Os resultados mostraram que o número de ligações cruzadas, tensão na ruptura e dureza Shore A são dependentes do sistema de vulcanização convencional, semi-eficiente ou eficiente, e da temperatura e do tempo de cozimento do latex de ambas as fontes. Os valores dessas propriedades encontrados para a borracha da mangabeira foram inferiores ao da borracha da seringueira. O maior valor de tensão de ruptura, dureza Shore e deformação encontrada para a borracha de seringueira foi alcançado utilizando o sistema convencional com 3 horas de cozimento sob 80°C. Esses valores são: 22 MPa, 42 Shore A e 895% o que é aproximadamente 150%, 68% e 25%, respectivamente, maiores do que os maiores valores encontrados para a borracha da mangabeira (8,8 MPa, 25 Shore A e 714%) que foi obtido utilizando o sistema semi-eficiente. As borrachas obtidas da mistura dos látex apresentaram, para composições inferiores a 20%, em massa de borracha de mangabeira, um comportamento similar a da seringueira mostrando ser viável a sua utilização para fabricação...
Abstract: Natural rubber is one of the most consumed polymer in the worldwide and pneumatic industry is responsible for approximately three fourths of total consumption. Hevea brasiliensis is the most important producer of natural rubber, being responsible for 99% of global production. The Hancornia speciosa Gomes is also produces white latex that can be tapped from the tree similarly to Hevea. Although it has been used commercially in emergency periods, nowadays Hancornia rubber has no technology use due to its low production and rubber quality. The latex blend can be a viable alternative to the use of mangabeira latex as one additional income besides of fruit commercialization. In this sense, the proposal of this work was to evaluate the influence of prevulcanization condition in the Hancornia speciosa Gomes (mangabeira) and Hevea brasiliensis (seringueira) latexes and also in its mixture, on the rubber proprieties. The latexes were prevulcanizated by conventional (CV), semi-efficient (SEV) and efficient (EV) vulcanization systems under temperatures of 60, 70 and 80 ° C. The crosslinked quantity was investigated by the swelling technique and the mechanical proprieties were obtained from tensile experiments and shore A hardness. The results showed that the quantity of crosslinked, stress at break and shore hardness are dependent of prevulcanization condition. The values of these proprieties found for mangabeira rubber were lower than the values found for the seringueira rubber. The highest stress at break, shore hardness and strain to seringueira and mangabeira rubber were obtained using the CV and SEV systems, respectively, under temperature of 80° C for 3 hours. Theses value are: 22 MPa, 42 shore A and 895% that are around 150%, 68% e 25%, respectively, higher than found to mangabeira rubber (8,8 MPa, 25 Shore A and 714%). The rubbers obtained from mixture of latex have the mechanical proprieties closed to the seringueira rubber for blends ...
Mestre
Bahari, Azlina. "Approaches to understanding diversity in rubber and carotenoid synthesis in Hevea brasiliensis latex". Thesis, University of Dundee, 2019. https://discovery.dundee.ac.uk/en/studentTheses/73b6fffb-faf0-4fb9-94f1-aa9bbb330154.
Texto completo da fontePiyatrakul, Piyanuch. "Caractérisation des gènes AP2/ERF impliqués dans le développement chez Hevea brasiliensis". Thesis, Montpellier, SupAgro, 2013. http://www.theses.fr/2013NSAM0033/document.
Texto completo da fonteHevea brasiliensis is the major industrial crop for natural rubber (NR) production. Ethephon stimulation, an ethylene releaser, is used for increasing latex production by prolonging latex flow and stimulating the metabolism required for the latex regeneration. However, the mechanism of ethylene action is not clearly elucidated in this species. Ethylene is an important signal regulating the plant development. AP2/ERF transcription factors, and especially Ethylene-Response Factors, play a crucial role in plant development and response to biotic and abiotic stresses. Ethylene production and signalling are also important to somatic embryogenesis, especially for species that are recalcitrant in in vitro culture.In this study, a comprehensive Hevea transcriptome was improved using additional RNA reads from reproductive tissues in a new assembly. The 30,342 contigs were annotated in the Gene Ontology database. The analysis of transcription factors led to 2,448 contigs being identified, which were classed in 58 transcription factor families. Six percent of the transcription factors corresponded to members from the AP2/ERF superfamily. The transcript accumulation of AP2/ERF genes was analyzed during somatic embryogenesis for callus lines with different regeneration potential and in various vegetative and reproductive tissue of Hevea. The relative transcript abundance were studied and showed that ERFs from group I, VII and VIII were abundant at all stages of the somatic embryogenesis as well as, in both immature and mature male and female flowers, zygotic embryos, leaf, bark and latex. Forty genes were identified as expression marker for callus with different plant regeneration potential regeneration capacity. Interestingly, fourteen expression marker genes were found that be able to predict the regeneration capacity of callus at proliferating calli, the early stage of somatic embryogenesis process. Fifty-nine expression marker genes were found in the various plant tissues. Several AP2/ERF genes were shown highly transcript accumulation in latex and were assigned as latex expression marker genes. Almost of latex expression marker genes belong to the ERF group VII. Base on conserved motif analysis showed this ERF group contained the conserved N-terminal motif (MCGGAII) involved in the N-end rule pathway. Subcellular localization and transactivation analyses suggested that HbERF-VII candidate genes encoded functional transcription factors
Carlos, Bruna Leonel. "Efeitos da membrana de látex na regeneração de defeito ósseo em tíbia de rato". Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/17/17142/tde-02042018-112204/.
Texto completo da fonteProblems of bone consolidation are a significant clinical challenge, as they generate high treatment costs, morbidities, and damages to the quality of life. The guided bone regeneration technique is used to improve the regeneration process of bone defects through the use of biological barriers that protect the site and favor the action of osteogenic cells. The natural latex membrane extracted from the rubber tree Hevea brasiliensis has been identified as a biomaterial promoting regeneration in different tissues, and for this reason chosen as the object of study of this research. The objective was to evaluate the effect of the use of natural latex membrane in the process of guided regeneration of bone defect in long bones of rats, through structural, radiological, microscopic analysis and the expression of osteogenic proteins. Sixty Wistar rats were equally divided into four groups (n = 15): latex membrane treated animals for one (L1) or four weeks (L4) and animals that received no specific treatment for one (C1) or four weeks (C4). A bone defect of 2.5 mm diameter was performed in the medial region of the left tibia of each animal. In the animals of the treated group, a latex membrane was positioned over the bone defects. After the experimental periods of one or four weeks, the animals were submitted to euthanasia, and the left tibia of each animal was dissected, cleaned of soft parts and submitted to macroscopic, densitometric, radiological, mechanical, histomorphometric, stereological and immunohistochemical analysis. The influence of the variable time and membrane as well as the time * membrane interaction on the data were evaluated. For the data referring to the osteocalcin immunostaining, a generalized linear model with independent factors was applied. For the rest of the results, a multivariate ANOVA analysis was performed with two independent factors. All comparisons were performed with Bonferroni adjustment and adopted a significance level of 5%. Statistically significant differences were observed in relation to the time variable, in which groups evaluated four weeks after surgery presented superior results for the measures of length (p <0.001), mass (p <0.001), maximal strength (p <0.001) and stiffness (P <0.001), as well as for measurements of radiological density (p = 0.008), bone mineral density (p = 0.017), neoformed bone volume (p <0.001) and type III collagen fibers (p <0.001) ). About the use of the latex membrane, the treated groups presented statistically superior results for analyzes of relative stiffness (p = 0.048), type I collagen fibers (p = 0.018), neoformed bone volume (p <0.001) and expression of Osteopontin (p = 0.037). We conclude that the use of latex membrane in guided bone regeneration in defects performed in rat tibiae significantly improved tissue regeneration.
Gomes, Willian Pereira [UNESP]. "Prevulcanização do látex natural extraído da hancornia speciosa gomes (Mangabeira) e da hevea brasiliensis (seringueira)". Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/136022.
Texto completo da fonteA borracha natural é um dos polímeros mais consumidos mundialmente, onde seu principal mercado é o setor pneumático com cerca de três quartos do consumo total. A seringueira é a mais importante produtora de borracha natural, sendo responsável por cerca de 99% da produção mundial A mangabeira é também uma arvore lactescente produzida quase em sua totalidade de forma extrativista e visada somente para a produção do seu fruto, a mangaba. Embora já ter sido utilizada comercialmente em períodos emergenciais, hoje a borracha natural provinda da mangabeira não tem qualquer utilização tecnológica, pois é considerada uma borracha de qualidade inferior. Neste trabalho foram produzidos filmes de borracha prevulcanizada com o látex de seringueira, de mangabeira e também com a mistura (m/m) do látex de mangabeira no látex de seringueira, nas proporções de 95/5, 90/10, 80/20, 70/30 e 60/40. Os resultados mostraram que o número de ligações cruzadas, tensão na ruptura e dureza Shore A são dependentes do sistema de vulcanização convencional, semi-eficiente ou eficiente, e da temperatura e do tempo de cozimento do latex de ambas as fontes. Os valores dessas propriedades encontrados para a borracha da mangabeira foram inferiores ao da borracha da seringueira. O maior valor de tensão de ruptura, dureza Shore e deformação encontrada para a borracha de seringueira foi alcançado utilizando o sistema convencional com 3 horas de cozimento sob 80°C. Esses valores são: 22 MPa, 42 Shore A e 895% o que é aproximadamente 150%, 68% e 25%, respectivamente, maiores do que os maiores valores encontrados para a borracha da mangabeira (8,8 MPa, 25 Shore A e 714%) que foi obtido utilizando o sistema semi-eficiente. As borrachas obtidas da mistura dos látex apresentaram, para composições inferiores a 20%, em massa de borracha de mangabeira, um comportamento similar a da seringueira mostrando ser viável a sua utilização para fabricação...
Natural rubber is one of the most consumed polymer in the worldwide and pneumatic industry is responsible for approximately three fourths of total consumption. Hevea brasiliensis is the most important producer of natural rubber, being responsible for 99% of global production. The Hancornia speciosa Gomes is also produces white latex that can be tapped from the tree similarly to Hevea. Although it has been used commercially in emergency periods, nowadays Hancornia rubber has no technology use due to its low production and rubber quality. The latex blend can be a viable alternative to the use of mangabeira latex as one additional income besides of fruit commercialization. In this sense, the proposal of this work was to evaluate the influence of prevulcanization condition in the Hancornia speciosa Gomes (mangabeira) and Hevea brasiliensis (seringueira) latexes and also in its mixture, on the rubber proprieties. The latexes were prevulcanizated by conventional (CV), semi-efficient (SEV) and efficient (EV) vulcanization systems under temperatures of 60, 70 and 80 ° C. The crosslinked quantity was investigated by the swelling technique and the mechanical proprieties were obtained from tensile experiments and shore A hardness. The results showed that the quantity of crosslinked, stress at break and shore hardness are dependent of prevulcanization condition. The values of these proprieties found for mangabeira rubber were lower than the values found for the seringueira rubber. The highest stress at break, shore hardness and strain to seringueira and mangabeira rubber were obtained using the CV and SEV systems, respectively, under temperature of 80° C for 3 hours. Theses value are: 22 MPa, 42 shore A and 895% that are around 150%, 68% e 25%, respectively, higher than found to mangabeira rubber (8,8 MPa, 25 Shore A and 714%). The rubbers obtained from mixture of latex have the mechanical proprieties closed to the seringueira rubber for blends ...
Agostini, Deuber Lincon da Silva [UNESP]. "Estudo dos componentes não isoprênicos do látex de Hevea brasiliensis indutores de angiogênese". Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/103766.
Texto completo da fonteAtualmente é comprovado o poder de indução de angiogênese e neoformação tecidual através de membranas de borracha natural de Hevea brasiliensis. Este trabalho apresenta um estudo sobre as propriedades e a caracterização das frações não isoprênicas, separadas por centrifugação do látex, utilizado como biomaterial na indução de angiogênese e de neoformação. As frações constituintes, F2 e F3 sem o tradicional agente estabilizante de hidroxido de amônio (NH4OH), foram liofilizadas para a redução da quantidade de água e estabilização, em seguida tratadas termicamente a temperatura de 40,60,80, 100, 120 e 140ºC e novamente liofilizadas, sendo caracterizada através das técnicas de Kjeldahl, Soxhlet, de espectroscopia de absorção no infravermelho (FT-IR), Ressonância Magnética Nuclear (RMn-13C). Difração de raios x (DRX), termogravimetria (TG) acoplado ao FT-IR (IG/FT-IR), calorimetria exploratória diferencial (DSC), eletroforese, dosagens de citocinas e síntese de óxido nítrico considerando o fator limitate do uso do látex como um material bioativo, que é a temperatura de tratamento térmico, realizado para a obtenção das membranas de borracha natural, em torno de 85ºC. Foi possível verificar que a fração F3 constituinte do látex, tem propriedades anti-inflamatórias e que a fração F2 possui propriedades pró-inflamatórias
Currently it is proven the hability of inducing angiogenesis and tissue neoformating through membranes of natural rubber Hevea brasiliensis, so this work presents a study on the properties and characterization of non-isoprene fractions, separated by centrifugation, the latex used as biomaterial for induction and neoformation of angiongenesis and lyophilized without the traditional stabilizing agent, ammonium hydroxide (NH4OH). The fractions constituents, F2 and F3 fractions were lyophilized without the traditional stabilizing agent, ammonium hydroxide (NH4OH). The fractions constituents, F2 and F3 fractions were lyophilized to reduce the amount of water and stabilization, and then heat treated at temperature of 40, 60, 80, 100, 120 and 140ºC bieng characterized by the techniques of kjeldahl, Soxhlet, of absorption spectroscopy infrared (FT-IR), Nuclear Magnetic Resonance (NMR-13C), X-ray Diffraction (XRD), thermogravimetry (TG) coupled to FT-IR (TG-IR), differential scanning calorimetry (DSC), electrosphoresis, serum cytokines and oxide nitric (NO) considering the limiting factor in the use of latex as a bioactive material, which is the thermal treatment temperature, held for obtaining membranes of natural rubber, about 85ºC. It was possible to verify that the fraction F3 constituent latex has anti-inflammatory and the fraction F2 take inflammatory properties
Agostini, Deuber Lincon da Silva. "Estudo dos componentes não isoprênicos do látex de Hevea brasiliensis indutores de angiogênese /". Bauru, 2013. http://hdl.handle.net/11449/103766.
Texto completo da fonteBanca: Mariselma Ferreira
Banca: Ivan Helmuth Bechtold
Banca: José Antonio Malmonge
Banca: Eduardo René Perez
Resumo: Atualmente é comprovado o poder de indução de angiogênese e neoformação tecidual através de membranas de borracha natural de Hevea brasiliensis. Este trabalho apresenta um estudo sobre as propriedades e a caracterização das frações não isoprênicas, separadas por centrifugação do látex, utilizado como biomaterial na indução de angiogênese e de neoformação. As frações constituintes, F2 e F3 sem o tradicional agente estabilizante de hidroxido de amônio (NH4OH), foram liofilizadas para a redução da quantidade de água e estabilização, em seguida tratadas termicamente a temperatura de 40,60,80, 100, 120 e 140ºC e novamente liofilizadas, sendo caracterizada através das técnicas de Kjeldahl, Soxhlet, de espectroscopia de absorção no infravermelho (FT-IR), Ressonância Magnética Nuclear (RMn-13C). Difração de raios x (DRX), termogravimetria (TG) acoplado ao FT-IR (IG/FT-IR), calorimetria exploratória diferencial (DSC), eletroforese, dosagens de citocinas e síntese de óxido nítrico considerando o fator limitate do uso do látex como um material bioativo, que é a temperatura de tratamento térmico, realizado para a obtenção das membranas de borracha natural, em torno de 85ºC. Foi possível verificar que a fração F3 constituinte do látex, tem propriedades anti-inflamatórias e que a fração F2 possui propriedades pró-inflamatórias
Abstract: Currently it is proven the hability of inducing angiogenesis and tissue neoformating through membranes of natural rubber Hevea brasiliensis, so this work presents a study on the properties and characterization of non-isoprene fractions, separated by centrifugation, the latex used as biomaterial for induction and neoformation of angiongenesis and lyophilized without the traditional stabilizing agent, ammonium hydroxide (NH4OH). The fractions constituents, F2 and F3 fractions were lyophilized without the traditional stabilizing agent, ammonium hydroxide (NH4OH). The fractions constituents, F2 and F3 fractions were lyophilized to reduce the amount of water and stabilization, and then heat treated at temperature of 40, 60, 80, 100, 120 and 140ºC bieng characterized by the techniques of kjeldahl, Soxhlet, of absorption spectroscopy infrared (FT-IR), Nuclear Magnetic Resonance (NMR-13C), X-ray Diffraction (XRD), thermogravimetry (TG) coupled to FT-IR (TG-IR), differential scanning calorimetry (DSC), electrosphoresis, serum cytokines and oxide nitric (NO) considering the limiting factor in the use of latex as a bioactive material, which is the thermal treatment temperature, held for obtaining membranes of natural rubber, about 85ºC. It was possible to verify that the fraction F3 constituent latex has anti-inflammatory and the fraction F2 take inflammatory properties
Doutor
Yusof, Faridah. "Factors affecting the formation of rubber from isopentenyl pyrophosphate in Hevea brasiliensis latex". Thesis, University of Hertfordshire, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361264.
Texto completo da fonteKuswanhadi. "Isolement et caractérisation des gènes ACS et ACO impliqués dans la biosynthèse de l’éthylène chez Hevea brasiliensis : évaluation de leur rôle dans la production de caoutchouc naturel". Montpellier 2, 2006. http://www.theses.fr/2006MON20201.
Texto completo da fonteBellacicco, Sophie. "Etude de l’impact de l’origine clonale du latex d’Hevea brasiliensis sur la composition biochimique du latex et la mésostructure du caoutchouc naturel". Thesis, Montpellier, SupAgro, 2014. http://www.theses.fr/2014NSAM0003.
Texto completo da fonteNatural rubber produced from Hevea brasiliensis latex possesses remarkable properties which have not been matched by its synthetic counterparts. However, this natural origin material presents a disadvantage: the significant variability of its properties. This variability has been partly ascribed to the 3 to 5% non isoprene components (lipids, proteins, sugars and minerals) present in the natural rubber. Among the factors that could be held responsible for this variability, clonal origin seems to be decisive.The main aim of this study was to evaluate the impact of clonal origin on the biochemical latex composition and on natural rubber mésostructural characteristics and also to study relationships between genotype, latex biochemical composition and rubber mesostructure. This study was conducted with five Hevea brasiliensis clones: GT1, RRIM600, PB235, PB217 and PB260. Before clonal characterization, preliminary studies were performed to determine the suitable sampling conditions in order to get the latex samples that represented as much as possible the clones. Fresh latex is an unstable material. It was decided to work on freeze-dried latex for the biochemical components analysis (except lipids) and for the natural rubber mesostructure study. Protocols for proteins and sugars' extractions on freeze-dried latex have been developed on the natural rubber solubilizing properties in organic media. Lipids extractions was performed according to the protocol developed by Liengrayoon (Liengprayoon , 2008) on fresh latex.The different results obtained on the latex biochemical composition and the natural rubber mesostructure allowed to clearly observe the clonal origin importance. Study of relationships between genotype and latex biochemical composition (PCA) has clearly shown that the clonal origin played an important role in the total variability of latex biochemical data. Analysis of relationships between latex biochemistry and natural rubber mesostructure helped highlight interesting correlations of lipids and proteins with mesostructure (mainly Mn and I).This biochemical analysis of clonal latex has proved to be appropriate for studying the clonal diversity and its repercussions on the natural rubber mesostructure. This approach of Hevea brasiliensis clonal diversity, and the knowledge gained from this study, provides a solid basis to be completed by further studies on different plantations, different clones and further biochemical and structural analyses
Gallois, Richard. "Métabolisme des nucléotides adényliques dans le latex de l'"Hevea brasiliensis". Effets de l'éthylène". Montpellier 2, 1998. http://www.theses.fr/1998MON20116.
Texto completo da fonteKerche-Silva, Leandra Ernst. "Avaliação in vitro e in vivo da capacidade antioxidante e antitumoral da fração C do látex de Hevea brasiliensis RRIM 600 /". Presidente Prudente, 2017. http://hdl.handle.net/11449/148926.
Texto completo da fonteBanca: Eduardo Rene Perez Gonzalez
Banca: Edgardo Alfonso Gomes Pineda
Banca: Antonio Hernandes Chaves Neto
Banca: Aneli de Melo Barbosa
Resumo: Biomateriais podem ser definidos como dispositivos que entram em contato com sistemas biológicos tanto na forma de sólidos quanto de líquidos e géis. Para um novo biomaterial, são necessários testes toxicológicos e de interação in vitro e in vivo. O látex é uma substância branca e leitosa que exsuda da casca da Hevea brasiliensis quando a mesma é perfurada e que tem sido apontado como um biomaterial promissor. O látex quando centrifugado em alta velocidade é separado em três frações: a fração com partículas de borracha, uma fração aquosa chamada fração C e uma fração de fundo chamada fração B. A fração C é a fração metabolicamente ativa do látex. Assim, o presente estudo investigou os potenciais efeitos antioxidantes, citotóxicos, genotóxicos e antitumorais da fração C do látex da Hevea brasiliensis. Para isso, foram utilizados os testes de sequestro de radicais livres e capacidade antioxidante total em meio in vitro sem células; o teste do MTT, o ensaio do cometa, avaliação de morte celular com coloração com Hoechst 33342 e Iodeto de Propídio (PI) e avaliação de parâmetros bioquímicos de estresse oxidativo em meio in vitro com duas linhagens celulares, a CHO-k1, linhagem de células normais de epitélio de ovário de hamster, e a B16F10, linhagem de células de melanoma murino; e a ação da fração C na indução de carcinoma de células escamosas (SCC) em camundongos SKH-1 por exposição crônica à radiação UVB. Nossos resultados mostraram que a fração C é antioxidante, com capacidade... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Biomaterials can be defined as devices that come in contact with biological systems in the form of solids, liquids and gels. In vitro and in vivo toxicological tests are needed for a new biomaterial to come out. Latex is a while and milky solution that exsudes from Hevea Brasiliensis bark when perforated, and it has been appointed as a new promising biomaterial. When centrifuged in high speed, latex can be separated in three parts: rubber particle fraction, aqueous C-serum fraction and a bottom fraction called B-serum. C-serum is the part that is metabolically active. In this way, the aim of this work was to investigate potential antioxidant, cytotoxic, genotoxic and antitumor effect of latex C-serum from Hevea brasiliensis. For this purpose, we used in vitro free-radical scavenger and total antioxidant capacity tests; MIT test, comet assay, staining with Hoechst 33342 and Propidium Iodide (PI) to evaluate cell death, and evaluation of biochemical parameters of oxidative stress in Chinese hamster ovary epithelium normal cell line, CHO-K1, and murine melanoma cell line, B16F10; and C-serum effects in the inductino of squamous cell carcinoma (SCC) in KKH-1 mice by chronic UVB exposure. Our results show that latex C-serum is an antioxidant compound that was able to scavenge HO and NO radicals and H2O2. C-serum did not after the cell viability in CHO-k1 cells and it did not promote DNA damage in these cells, it did not after the levels of apoptotic and necrotic cells for this cell lineage and did not alter total thiol and MDA levels in these cells. However, for B16F10 cells, latex C-serum presented antitumor effect, reducing cell viability, inducing DNA damage and cell death, and altering total thiol and MDA levels in these cells. In the animals chronically exposed to UVA radiation, latex C-serum proteted the erythrocytes and skin cells from oxidative stress promote by the irradiation, and... (Complete abstract electronic access below)
Doutor
Salomez, Mélanie. "Etude du rôle des microorganismes dans les modifications biochimiques intervenant lors de la maturation des coagulums de latex d’Hevea brasiliensis : impact sur les propriétés du caoutchouc naturel sec". Thesis, Montpellier, SupAgro, 2014. http://www.theses.fr/2014NSAM0002.
Texto completo da fonteThe overall objective of this thesis was to study the microbial mechanisms involved in the evolution of the structure and the properties of the natural rubber from Hevea brasiliensis during the maturation of latex and cup-coagula. For this, three levels of analyses were performed on maturation experiments under controlled conditions: dry rubber structure and properties, biochemistry and microbial flora. After a methodology development phase aiming at (i) optimizing maturation conditions in a controlled chamber and (ii) defining suitable DNA extraction methods, samples of serum and dry rubber coagulum were produced at different times and under different maturation treatments varying three parameters: the presence of microorganisms, the presence of oxygen, and the latex coagulation method. Dry rubber analyses concerned macrostructure (P0, P30 and PRI) and mesostructure (Mw, Mn and total gel). The microbial flora was analyzed using several complementary methods: plate-counts, total DNA determination, cloning / sequencing and 454 pyrosequencing. The objective was to assess microbial diversity on field and in latex, and to follow the dynamics of their evolution during maturation in a controlled environment. Various biochemical investigations were performed on latex, serum and dry rubber (nitrogen content, proteins, lipids, sugars, quebrachitol, organic acids). The results were then analyzed for correlations to propose mechanisms linking changes in dry rubber properties, latex and coagula biochemistry, and their evolution under the action of microorganisms and enzymes. Some ideas for improving technical routes in the process are also proposed
Friolani, Milena [UNESP]. "Utilização da biomembrana de látex de seringueira (Hevea brasiliensis) em lesões diafragmáticas de coelhos: estudo experimental". Universidade Estadual Paulista (UNESP), 2008. http://hdl.handle.net/11449/89027.
Texto completo da fonteConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Tendo em vista as propriedades de aceleração do processo cicatricial com utilização da biomembrana de látex, este trabalho teve como objetivo avaliar o comportamento de retalho de biomembrana natural de látex, em lesões diafragmáticas induzidas experimentalmente em coelhos. Utilizaram-se 15 coelhos sadios, raça Nova Zelândia, adultos, machos e fêmeas, tendo como acesso ao diafragma, o 8º espaço intercostal direito. Os animais foram divididos, aleatoriamente, em cinco grupos experimentais de três cada, e avaliados diariamente desde o dia da cirurgia até a eutanásia, quanto ao comportamento, freqüência respiratória e cardíaca, cicatrização externa. Os animais foram eutanasiados aos 15, 30, 45, 60 e 90 dias de pós cirúrgico, obtendo-se uma avaliação macroscópica e microscópica do conjunto diafragma/enxerto. Todos os animais apresentaram evolução clínica satisfatória. Macroscopicamente, em todos os grupos experimentais observou-se boa cicatrização na região do implante, com exceção de um dos animais eutanasiados aos quinze dias. Após quinze dias, houve neoformação tecidual, e após trinta dias do ato operatório, em todos animais observou-se aderência do fígado e do pulmão na área de implante. As observações clínico-cirúrgicas complementadas pela análise das alterações histológicas, permitiram concluir pela indicação do emprego da membrana de látex em lesões diafragmáticas reparadoras, em razão da facilidade de obtenção, custo baixo, fácil aplicabilidade, resistência e resposta satisfatória em relação ao tempo de cicatrização.
Having in mind the acceleration properties of the cicatricial process by using the latex bio-membrane, the present paper was aimed at evaluating the behavior of the natural latex bio-membrane flap in diaphragmatic lesions experimentally induced in rabbits. Fifteen healthy New Zealand rabbits, adults, males and females were used, having the eighth right intercostal space as an access to the diaphragm. The animals were randomly assigned to five experimental groups, each with three rabbits. They were evaluated daily from the day of surgery to the day of euthanasia in relation to behavior, respiratory and cardiac frequencies and external cicatrization. The animals were euthanized in 15, 30, 45, 60 and 90 days after the surgery and it was obtained a macroscopic and microscopic evaluation of the set diaphragm/graft. All rabbits presented a satisfactory clinical evolution. Macroscopically, in all experimental groups it was observed a good cicatrization of the implant region, except for one animal that was euthanized in 15 days. After fifteen days, there was tissular neo-formation and thirty days after surgery in all animals it was observed the adherence of the liver and lungs in the implant area. The clinical surgical observations complemented by the analysis of histological alterations allowed the conclusion in favor of the indication of using the latex membrane in reparative diaphragmatic lesions because of the easy obtainment, low cost, easy applicability, resistance, and satisfactory response in relation to the cicatrization time.
Andrade, Thiago Antonio Moretti de. "Atividade da biomembrana de látex natural da seringueira Hevea brasiliensis na neoformação tecidual em camundongos". Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/17/17138/tde-08072008-143229/.
Texto completo da fonteThe natural latex biomembrane (NLB) from Hevea brasiliensis rubber tree, used as dressing in the treatment of human chronic ulcers, has been showed efficient in the debridement and the granulation stimulation, accelerating the healing. Its mechanism of action is still unknown, becoming important to evaluate its activity as implantation in the tissue induction, comparing it with the other implants and with the normal healing (SHAM). Mice C57BL/6, consisting of 5 distinct groups had been used of the dorsal subcutaneous implantation (1cm2): 15 implanted with NLB; 15 with surgical GLOVE (unnatural latex); 15 with ePTFE (expanded polytetrafluorethylene - synthetic implantation) and 15 without implant (SHAM). The activity of the implants was evaluated in 2nd, 7th and 14th days. Five animals for group each time were sacrificed for biopsies with 4mm punch. All skin of the implanted area was cut and photographed. The samples had been submitted to the histology studies for haematoxylin-eosin for counting the inflammatory cells, fibroplasia and angiogenesis, using \"Cell Counter\" plugin in the ImageJ® software; by Gomori\'s thrichrome for collagen quantification using \"Threshold\" in the ImageJ®, and iNOS, IL-beta1, VEGF and TGF-beta1 immunohistochemistry. From the biopsies macerated supernatant, the myeloperoxidase assay had been carried through (MPO), IL-beta1 and of TGF-beta1 by ELISA. Macroscopically, it was observed a big amount of new tissue formed in the NLB implanted animals on 2nd day, different of the other groups. In histological analyze by H&E, it was observed that the NLB in 2nd day stimulated dense inflammatory infiltrated, mainly by neutrophils, followed of bigger production of MPO and IL-beta1, different of the other treatments (P<0,01). After 7 and 14 days, the amount of IL-beta1 in the groups GLOVE and SHAM were greater than the NLB and ePTFE, showing the balance in the initial stimulation of the inflammatory activity by the NLB. About angiogenesis, both groups (NLB and GLOVE) after 7 and 14 days had presented greater formation of vessels than ePTFE and SHAM (P<0,01).However, in the immunohistochemistry was observed a low VEGF expression in the NLB group in 7th and 14th days. Related to fibroplasia, ePTFE after 7 days presented greater fibroplasia than all the groups (P<0,01). In 14th day, the NLB presented an important fibroplasia, even so without statistic difference between the groups. The collagen proliferation evaluated by the ImageJ® (\"Threshold\") applied in Gormori\'s thrichrome stained biopsies, the implants showed similar results, also with the SHAM, except in 14th day that ePTFE presented bigger collagen proliferation than the GLOVE (P<0,01).The SHAM group presented greater concentration of TGF-beta1 than the other groups in the seventh day (P<0,01), equal to the NLB and the GLOVE in 14th, however bigger than ePTFE (P<0,01).In conclusion, natural latex biomembrane (NLB) from Hevea brasiliensis rubber tree acts significantly in the inflammatory phase of the healing process, important in the neutrophilic recruitment to injury local, confirmed quantitatively by MPO and IL-beta1 concentrations and by immuno histochemistry. This fact seems to influence directly the subsequent phases of the healing process, confirmed for its stimulatory capacity of the angiogenesis, probably not influenced by VEGF, and the fibroplasia stimulation independent of TGF-beta1 and without modification in the collagen production.
Baudoin, Marion. "Impact de la taille des particules de caoutchouc du latex d’Hevea brasiliensis sur leurs propriétés aux interfaces fluides et en feuilles de caoutchouc sec". Electronic Thesis or Diss., Université de Rennes (2023-....), 2024. http://www.theses.fr/2024URENS038.
Texto completo da fonteThe aim of this thesis is to gain a deeper understanding of the coagulation process of the two size classes of rubber particles derived from Hevea brasiliensis latex, and to establish a link with the mechanical properties of the final rubber. The originality lies in a multi-scale, multi-disciplinary approach, covering the analysis of native particles and their self-organization in the liquid state, as well as the mechanical properties of dry films in the form of rubber sheets (mini ADS). The study was carried out on two particle sizes from the RRIM600 and PB235 clones. The first part is a new liquid/air approach using a Langmuir trough, with particle adsorption kinetics at the interface monitored using complementary techniques such as ellipsometry, tensiometry, rheology and Brewster angle microscopy. The first stages of coagulation and the organization of particle components were observed by atomic force microscopy. In the second part, these organizations were linked to the mechanical properties of dry rubber sheets using uniaxial tensile tests. This work opens up new perspectives by linking molecular processes to the macroscopic properties of natural rubber, thus broadening research lines in this field
Friolani, Milena. "Utilização da biomembrana de látex de seringueira (Hevea brasiliensis) em lesões diafragmáticas de coelhos : estudo experimental /". Jaboticabal : [s.n.], 2008. http://hdl.handle.net/11449/89027.
Texto completo da fonteAbstract: Having in mind the acceleration properties of the cicatricial process by using the latex bio-membrane, the present paper was aimed at evaluating the behavior of the natural latex bio-membrane flap in diaphragmatic lesions experimentally induced in rabbits. Fifteen healthy New Zealand rabbits, adults, males and females were used, having the eighth right intercostal space as an access to the diaphragm. The animals were randomly assigned to five experimental groups, each with three rabbits. They were evaluated daily from the day of surgery to the day of euthanasia in relation to behavior, respiratory and cardiac frequencies and external cicatrization. The animals were euthanized in 15, 30, 45, 60 and 90 days after the surgery and it was obtained a macroscopic and microscopic evaluation of the set diaphragm/graft. All rabbits presented a satisfactory clinical evolution. Macroscopically, in all experimental groups it was observed a good cicatrization of the implant region, except for one animal that was euthanized in 15 days. After fifteen days, there was tissular neo-formation and thirty days after surgery in all animals it was observed the adherence of the liver and lungs in the implant area. The clinical surgical observations complemented by the analysis of histological alterations allowed the conclusion in favor of the indication of using the latex membrane in reparative diaphragmatic lesions because of the easy obtainment, low cost, easy applicability, resistance, and satisfactory response in relation to the cicatrization time.
Orientador: Carlos Roberto Daleck
Coorientadora: Cláudia Sampaio Fonseca Repetti
Banca: Maria Rita Fernandes Machado
Banca: Celso Sanches Braccialli
Mestre
Caetano, Guilherme Ferreira. "Células mesenquimais estromais multipotentes derivadas do tecido adiposo e fração proteica do látex natural (Hevea brasiliensis) associados à scaffolds de policaprolactona e grafeno na osteogênese experimental". Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/17/17138/tde-22082017-171808/.
Texto completo da fonteThe increment of life expectancy and frequency of chronic diseases in the population has led to an increasing incidence of chronic bone defects. Conventional treatment is based on autologous transplantation, which depends on extremely invasive approaches. A promising proposal is to obtain healthy tissues in laboratories using porous three-dimensional matriz (scaffolds), which enable cellular growth and differentiation of mesenchymal stem cells (MSCs). Scaffolds can be optimized to provide adequate vascularization, a critical event to bone regeneration. MSCs have potential for differentiation, immunoregulation and angiogenesis. F1 natural latex protein from Hevea brasiliensis rubber tree presents important angiogenic and healing activity. The objective of this work was to investigate the influence of pre-colonized polycaprolactone (PCL) scaffolds on experimental in vitro and in vivo osteogenesis (xenotransplantation) and also the safety and influence of F1 protein on MSCs seeded on PCL and PCL reinforced with different concentrations of graphene scaffolds (PCL/graphene) in cell proliferation and osteogenic differentiation. MSCs were isolated from human adipose tissue (ADSCs), characterized by positive and negative markers and also in vitro differentiation. PCL Scaffolds, produced by an additive manufacturing technique, were evaluated for cell adhesion/viability potential (MTT assay), osteogenic differentiation (alizarin red) and in vivo xenogenic grafting potential for osteointegration and osteoinduction evaluated by histology and immunohistochemistry. F1 latex protein, prepared in different concentrations, was evaluated in contact with ADSCs and 3T3 fibroblasts culture in vitro regarding to cytotoxicity (MTT), proliferative potential (tritiated thymidine), migratory (scratch assay) and osteogenic induction (alkaline phosphatase). PCL scaffolds were reinforced with graphene (PCL/graphene scaffolds), coated with F1 protein (adsorption) and evaluated for cell viability/proliferation assay (Alamar blue) and osteogenic differentiation (alkaline phosphatase and alizarin red). ADSCs showed low percentage for negative markers, high percentage for positive markers and differentiation properties in vitro, providing enough information on the successful isolation and maintenance of human ADSCs. PCL scaffolds showed non-toxicity activity and osteogenic differentiation induced by culture medium. PCL scaffolds, pre-colonized and non-colonized with ADSCs, were implanted in a critical calvarial defect in rats. The group of rats which received scaffolds with ADSCs to treat the bone defect had improved bone formation with direct and indirect participation of ADSCs to the bone repair process. To in vitro assays with F1 (2D culture model), proliferative stimulus was observed to F1 0.00001% and 0.0001% samples, in addition to a higher percentage of cell migration to 0.001% and 0.0001%, different from control. PCL/graphene scaffolds demonstrated proliferative stimulation when colonized by ADSCs and this stimulus was even higher to F1 coated PCL/graphene scaffolds, mainly to 0.75% graphene. Although F1 have not enhanced osteogenic differentiation on 2D cell culture model, the stimulus was observed to F1 coated scaffolds with higher alkaline phosphatase activity. This work demonstrated success in the use of ADSCs and scaffolds for bone regeneration and presented two promising products to be applied in tissue engineering field, such as, scaffolds with graphene reinforcement at low concentration and F1 latex protein to improve cell proliferation and differentiation.
Pujade-Renaud, Valérie. "Recherche de marqueurs moleculaires de la production de latex et de sa stimulation par l'ethylene chez hevea brasiliensis". Paris 11, 1993. http://www.theses.fr/1993PA112508.
Texto completo da fontePagnano, Leonardo de Oliveira [UNESP]. "Análise da cicatrização na pele de coelhos após tratamentos de feridas com biomateriais associados à fração de proteína do látex natural da seringueira (Hevea brasiliensis)". Universidade Estadual Paulista (UNESP), 2009. http://hdl.handle.net/11449/101102.
Texto completo da fonteConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
O objetivo deste trabalho foi avaliar o potencial de cicatrização de uma fração de proteína extraída do látex da seringueira em diferentes concentrações (0,01% e 0,001%) associada a diferentes biomateriais (Fibracol plusÒ e ácido hialurônico a 1%). Utilizaram-se 36 coelhos albinos da raça Nova Zelândia Branco submetidos à realização de 4 feridas em cada orelha. Dividiu-se o experimento em etapas de acordo com a análise do período pós-operatório (3º, 7º, 14º e 21º dias), sendo utilizados 9 animais para cada etapa. Na primeira etapa (3º dia de pósoperatório), os animais foram numerados aleatoriamente de 1 a 9, sendo que em 3 animais, nas orelhas esquerdas, as feridas foram tratadas com solução salina (T1) e nas orelhas direitas, as feridas foram tratadas com membrana de Fibracol plus® + FrHb1 a 0,01% (T2). Em outros 3 animais, realizaram-se os mesmos procedimentos, diferenciando os tratamentos, onde nas feridas das orelhas esquerdas o tratamento foi com Fibracol plus® (T3) e nas feridas das orelhas direitas Fibracol plus® + FrHb1 a 0,001% (T4). Nos 3 animais restantes, seguiram-se os mesmos procedimentos, inserindo nas feridas das orelhas esquerdas ácido hialurônico a 1% + FrHb1 a 0,01% (T5) e nas feridas das orelhas direitas ácido hialurônico a 1% + FrHb1 a 0,001% (T6). Os animais foram sacrificados no 3º dia de pós-operatório e as feridas foram analisadas macroscopicamente e em seguida separadas para a análise histológica. Estes procedimentos foram repetidos para as etapas de 7, 14 e 21 dias de pós-operatório. Os segmentos de tecidos com as feridas foram fixados em solução de Bouin por 24 horas, e processados rotineiramente, para inclusão em paraplast e posterior avaliação histológica e morfométrica. A morfometria foi realizada por meio do sistema...
The aim of this study was to evaluate the potential for healing of a fraction of protein extracted from the latex of rubber trees in different concentrations (0.01% and 0.001%) associated with various biomaterials (Fibracol plus®1 and hyaluronic acid to 1%). There were used 36 New Zealand White rabbits underwent achievement of 4 wounds on each ear. The experiment was divided into stages according to the analysis of the postoperative period (3, 7, 14 and 21 days), and 9 animals used for each step. In the first stage (day 3 post-surgery), animals were randomly numbered from 1 to 9, with 3 animals in the left ear, the wounds were treated with saline (T1) and the right ear, the wounds were treated with membrane of Fibracol plus® + FrHb1 to 0.01% (T2). In 3 other animals, the same procedures were held, differing treatments, where the wounds of the left ear they were treated with Fibracol plus® (T3) and the wounds of the right ears Fibracol Plus® + FrHb1 to 0.001% (T4). In the 3 remaining animals, there was followed by the same procedures, including the ears wounds hyaluronic acid at 1% + FrHb1 to 0.01% (T5) and right ears wounds of hyaluronic acid 1% + FrHb1 a 0.001% (T6). The animals were sacrificed at 3 days postoperatively and the wounds were examined macroscopically and then separated for histological analysis. These procedures were repeated on the steps of 7, 14 and 21 days postoperatively. The segments of the injured tissues were fixed in Bouin solution for 24 hours and routinely processed for inclusion in paraplastic and subsequent histologic and morphometric evaluation. The morphometry was performed using the image analyzing system (Image Pro-PLUS2) and the evaluation of healing was done by enumeration of leukocytes and fibroblasts. The data were subjected to statistical analysis (ANOVA and Tukey test at 5%)... (Complete abstract click electronic access below)
Lacrotte, Régis. "Etude des relations entre la teneur en sucres du latex et la production : approche des mécanismes du chargement en saccharose des laticifères d'"Hevea brasiliensis" Muell. Arg". Montpellier 2, 1991. http://www.theses.fr/1991MON20245.
Texto completo da fontePagnano, Leonardo de Oliveira. "Análise da cicatrização na pele de coelhos após tratamentos de feridas com biomateriais associados à fração de proteína do látex natural da seringueira (Hevea brasiliensis) /". Jaboticabal : [s.n.], 2009. http://hdl.handle.net/11449/101102.
Texto completo da fonteBanca: Isabel Cristina Boleli
Banca: Antônio Carlos Alessi
Banca: Joaquim Coutinho Netto
Banca: João José Lachat
Resumo: O objetivo deste trabalho foi avaliar o potencial de cicatrização de uma fração de proteína extraída do látex da seringueira em diferentes concentrações (0,01% e 0,001%) associada a diferentes biomateriais (Fibracol plusÒ e ácido hialurônico a 1%). Utilizaram-se 36 coelhos albinos da raça Nova Zelândia Branco submetidos à realização de 4 feridas em cada orelha. Dividiu-se o experimento em etapas de acordo com a análise do período pós-operatório (3º, 7º, 14º e 21º dias), sendo utilizados 9 animais para cada etapa. Na primeira etapa (3º dia de pósoperatório), os animais foram numerados aleatoriamente de 1 a 9, sendo que em 3 animais, nas orelhas esquerdas, as feridas foram tratadas com solução salina (T1) e nas orelhas direitas, as feridas foram tratadas com membrana de Fibracol plus® + FrHb1 a 0,01% (T2). Em outros 3 animais, realizaram-se os mesmos procedimentos, diferenciando os tratamentos, onde nas feridas das orelhas esquerdas o tratamento foi com Fibracol plus® (T3) e nas feridas das orelhas direitas Fibracol plus® + FrHb1 a 0,001% (T4). Nos 3 animais restantes, seguiram-se os mesmos procedimentos, inserindo nas feridas das orelhas esquerdas ácido hialurônico a 1% + FrHb1 a 0,01% (T5) e nas feridas das orelhas direitas ácido hialurônico a 1% + FrHb1 a 0,001% (T6). Os animais foram sacrificados no 3º dia de pós-operatório e as feridas foram analisadas macroscopicamente e em seguida separadas para a análise histológica. Estes procedimentos foram repetidos para as etapas de 7, 14 e 21 dias de pós-operatório. Os segmentos de tecidos com as feridas foram fixados em solução de Bouin por 24 horas, e processados rotineiramente, para inclusão em paraplast e posterior avaliação histológica e morfométrica. A morfometria foi realizada por meio do sistema... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The aim of this study was to evaluate the potential for healing of a fraction of protein extracted from the latex of rubber trees in different concentrations (0.01% and 0.001%) associated with various biomaterials (Fibracol plus®1 and hyaluronic acid to 1%). There were used 36 New Zealand White rabbits underwent achievement of 4 wounds on each ear. The experiment was divided into stages according to the analysis of the postoperative period (3, 7, 14 and 21 days), and 9 animals used for each step. In the first stage (day 3 post-surgery), animals were randomly numbered from 1 to 9, with 3 animals in the left ear, the wounds were treated with saline (T1) and the right ear, the wounds were treated with membrane of Fibracol plus® + FrHb1 to 0.01% (T2). In 3 other animals, the same procedures were held, differing treatments, where the wounds of the left ear they were treated with Fibracol plus® (T3) and the wounds of the right ears Fibracol Plus® + FrHb1 to 0.001% (T4). In the 3 remaining animals, there was followed by the same procedures, including the ears wounds hyaluronic acid at 1% + FrHb1 to 0.01% (T5) and right ears wounds of hyaluronic acid 1% + FrHb1 a 0.001% (T6). The animals were sacrificed at 3 days postoperatively and the wounds were examined macroscopically and then separated for histological analysis. These procedures were repeated on the steps of 7, 14 and 21 days postoperatively. The segments of the injured tissues were fixed in Bouin solution for 24 hours and routinely processed for inclusion in paraplastic and subsequent histologic and morphometric evaluation. The morphometry was performed using the image analyzing system (Image Pro-PLUS2) and the evaluation of healing was done by enumeration of leukocytes and fibroblasts. The data were subjected to statistical analysis (ANOVA and Tukey test at 5%)... (Complete abstract click electronic access below)
Doutor
Kerche, Silva Leandra Ernst [UNESP]. "Avaliação in vitro e in vivo da capacidade antioxidante e antitumoral da fração C do látex de Hevea brasiliensis RRIM 600". Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/148926.
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Biomateriais podem ser definidos como dispositivos que entram em contato com sistemas biológicos tanto na forma de sólidos quanto de líquidos e géis. Para um novo biomaterial, são necessários testes toxicológicos e de interação in vitro e in vivo. O látex é uma substância branca e leitosa que exsuda da casca da Hevea brasiliensis quando a mesma é perfurada e que tem sido apontado como um biomaterial promissor. O látex quando centrifugado em alta velocidade é separado em três frações: a fração com partículas de borracha, uma fração aquosa chamada fração C e uma fração de fundo chamada fração B. A fração C é a fração metabolicamente ativa do látex. Assim, o presente estudo investigou os potenciais efeitos antioxidantes, citotóxicos, genotóxicos e antitumorais da fração C do látex da Hevea brasiliensis. Para isso, foram utilizados os testes de sequestro de radicais livres e capacidade antioxidante total em meio in vitro sem células; o teste do MTT, o ensaio do cometa, avaliação de morte celular com coloração com Hoechst 33342 e Iodeto de Propídio (PI) e avaliação de parâmetros bioquímicos de estresse oxidativo em meio in vitro com duas linhagens celulares, a CHO-k1, linhagem de células normais de epitélio de ovário de hamster, e a B16F10, linhagem de células de melanoma murino; e a ação da fração C na indução de carcinoma de células escamosas (SCC) em camundongos SKH-1 por exposição crônica à radiação UVB. Nossos resultados mostraram que a fração C é antioxidante, com capacidade para sequestrar os radicais HO• e NO• e o H2O2. A fração C não alterou a viabilidade celular das células CHO-k1, não induziu danos no DNA dessas células, não induziu apoptose e necrose e nem alterou a quantidade de tiol total e de malonaldeído (MDA) nessas células. No entanto, para a linhagem celular B16F10, a fração C mostrou atividade antitumoral, reduzindo a viabilidade celular, induzindo danos no material genético, induzindo morte celular e alterando os níveis de tiol e MDA nessas células. Nos animais que foram expostos cronicamente à radiação UVB, a fração C protegeu os eritrócitos e a pele dos animais do estresse oxidativo promovido pela irradiação e protegeu as células da pele de transformação maligna para SCC. Em resumo, nossos resultados mostraram que a fração C do látex da H. brasiliensis apresenta propriedades terapêuticas antioxidantes e antitumorais.
Biomaterials can be defined as devices that come in contact with biological systems in the form of solids, liquids and gels. In vitro and in vivo toxicological tests are needed for a new biomaterial to come out. Latex is a white and milky solution that exsudes from Hevea brasiliensis bark when perforated, and it has been appointed as a new promising biomaterial. When centrifuged in high speed, latex can be separated in three parts: rubber particle fraction, aqueous C-serum fraction and a bottom fraction called B-serum. Cserum is the part that is metabolically active. In this way, the aim of this work was to investigate potential antioxidant, cytotoxic, genotoxic and antitumor effects of latex Cserum from Hevea brasiliensis. For this purpose, we used in vitro free-radical scavenger and total antioxidant capacity tests; MTT test, comet assay, staining with Hoechst 33342 and Propidium Iodide (PI) to evaluate cell death, and evaluation of biochemical parameters of oxidative stress in Chinese hamster ovary epithelium normal cell line, CHO-k1, and murine melanoma cell line, B16F10; and C-serum effects in the induction of squamous cell carcinoma (SCC) in SKH-1 mice by chronic UVB exposure. Our results show that latex C-serum is an antioxidant compound that was able to scavenge HO• and NO• radicals and H2O2. C-serum did not alter the cell viability in CHO-k1 cells and it did not promote DNA damage in these cells, it did not alter the levels of apoptotic and necrotic cells for this cell lineage and did not alter total thiol and MDA levels in these cells. However, for B16F10 cells, latex C-serum presented antitumor effect, reducing cell viability, inducing DNA damage and cell death, and altering total thiol and MDA levels in these cells. In the animals chronically exposed to UVB radiation, latex C-serum protected the erythrocytes and skin cells from oxidative stress promoted by the irradiation, and prevented skin cells from malignant transformation to SCC. In summary, this work shows that latex C-serum from Hevea brasiliensis present antioxidant and antitumor therapeutic properties.
Musigamart, Natedao. "Study of the role of lipids from maturated coagula from Hevea brasiliensis latex on natural rubber behavior in oxidative conditions". Thesis, Montpellier, SupAgro, 2015. http://www.theses.fr/2015NSAM0004/document.
Texto completo da fonteNatural rubber (NR), a derived product from H. brasiliensis latex, is known for its high mechanical properties that are, for some, superior to those of its synthetic counterparts. However, the high degree of unsaturation of poly(cis-1,4-isoprene) makes it susceptible to thermo-oxidation. Fortunately, NR is endowed with non-isoprene components of which some have antioxidant properties. Especially, lipids, the main non-isoprene component retained in NR, have been reported to contain antioxidant substances, especially tocotrienols. It is well known that during the maturation of latex coagula, both NR physical properties and chemical composition are altered, but the complex mechanisms of this alteration are still to be elucidated. In the present work, the evolution of some native antioxidant molecules during maturation was followed in relation with some physical properties. Two experimental conditions of maturation were chosen. The first experiment involved uncontrolled conditions based on traditional unsmoked (USS) or ribbed smoked sheet (RSS) processing, while the second was performed in a dedicated maturation device with full control of environmental factors (relative humidity, temperature and oxygen content) followed by a processing based on that of Technically Specified Rubber (TSR). The evolution of samples during maturation was studied at different scales: bulk properties (P0, P30 and PRI), mesostructure (% gel content, Mw and Mn) and biochemical composition (lipids components). In parallel, in vitro antioxidant activity of NR lipid extracts was also investigated using an optimized DPPH method. Lipid quantity and quality evolved during maturation, especially under aerobic conditions. The total amount of lipid extract decreased, with a release of free fatty acids at early stage of maturation followed by a later decrease, unsaturated fatty acids being the first to disappear. The amount of extractable free γ-tocotrienol did not change much during maturation, while its esterified form was enriched in saturated fatty acids. The antioxidant activity measured in vitro correlated well with free γ-tocotrienol concentration but not with the resistance of rubber to thermo-oxidation assessed by P30 or PRI. Indeed, the in vitro conditions of measurement were far from those occurring inside rubber material. The localization of antioxidants in rubber and especially their physical possibility to interact with the double bonds of poly(cis-1,4-isoprene) or with oxidant species should be further investigated to understand what drives the drop of P30 along maturation time. Non extractable lipids or more polar non-isoprene molecular species (proteins, polyphenols, etc…) could also influence the resistance to thermo-oxidation
Dusotoit-Coucaud, Anaïs. "Caractérisations physiologique et moléculaire des transporteurs de sucres et de polyols des cellules laticifères chez "Hevea brasiliensis", en relation avec la production de latex". Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2009. http://tel.archives-ouvertes.fr/tel-00725589.
Texto completo da fonteAlves, Maxley Martins. "INFLUÊNCIA DO SORO LÁTEX NATURAL DA SERINGUEIRA Hevea Brasiliensis SOBRE A RESPOSTA INFLAMATÓRIA AGUDA INDUZIDA POR SEPSE: ESTUDO EXPERIMENTAL EM RATOS". Pontifícia Universidade Católica de Goiás, 2014. http://localhost:8080/tede/handle/tede/2985.
Texto completo da fonteThe acute inflammatory answer is a manifestation of the organism triggered by an infectious or non-infectious taunting. Predisposal factors are, for instance: bacteria, viruses, amongst other microorganisms or traumas. It is an internal survival mechanism. The development of a cascade of immunological events in an attempt of destroying an aggressive agent, with cardiologic, hemodynamic, respiratory, renal, endocrine, metabolic, gastrointestinal and hematological alterations occurs determining a syndrome clinic case. Vascular and immunological alterations trigger a counter balance inflammatory response. Recent researches using a specific derived fraction of the natural gum of Hevea brasiliensis rubber tree, called Hev b 13, has shown induction capability to synthesize interleukin 10 (IL-10) in vitro, stimulating the anti-inflammatory response that may result in homeostasis. These evidences are assessed with high mortality sepis induction, after surgical procedure with gastric, intestinal and pancreatic damaging and strain infusion of Acinetobacter baumanni of resistance profile to multiple antibiotics tested. In dose 0,5 mg/kg of Hev b 13 solution, subcutaneous, similarities were observed in the survival of animals treated with this solution and the control group, treated with 1 ml of SF0, 9% (p= 0,8106). The laboratorial analysis, on the other hand, showed total leukocytes reckoning (p = 0,0207) and total lymphocyte (p= 0,0032) with statistically significant differences. In further counting there was no significant difference (p>0,05). The Hev b 13 solution may lead to the induction of reducing the amplification of immunological cellular cascade, reducing the production of total leukocytes and lymphocytes, with effect over the immunological response, anti-inflammatory effect. The experiment induced synthesis of interleukin-10 (IL-10) and tumor necrosis factor (TNF). Rats receiving Hev b 13, lung tissue showed lesser involvement of inflammatory cells.
A resposta inflamatória aguda é uma manifestação do organismo desencadeada por um insulto. Fatores que predispõem são, por exemplo: bactérias, vírus, dentre outros micro-organismos ou traumas. É um mecanismo interno de sobrevivência. A resposta inflamatória leva ao desenvolvimento de uma cascata de eventos imunológicos na tentativa de destruir o agente agressor, com alterações cardiológicas, hemodinâmicas, respiratórias, renais, endocrinometabólicas, gastrointestinais e hematológicas determinando um quadro clínico sindrômico. As alterações vasculares e imunológicas desencadeiam uma resposta de contra-balanço inflamatória. Pesquisas recentes utilizando uma fração específica derivada do látex natural da seringueira Hevea brasiliensis, denominada Hev b 13, tem mostrado capacidade de induzir síntese de interleucina 10 (IL-10) in vitro, estimulando a resposta anti-inflamatória, podendo resultar em homeostase. Estas evidências são avaliadas no modelo experimental adotado com indução de sepse grave, após procedimento cirúrgico com lesões gástrica, intestinal e pancreática, além de infusão de cepas de Acinetobacter baumanni com perfil de resistência a múltiplos antibióticos testados. Foi infundido solução Hev b 13 via subcutânea na dosagem 0,5 mg/Kg. Observou-se semelhança na sobrevida dos animais que foram tratados com esta solução e os animais do grupo controle, tratados com 1 ml de SF0,9% (p =0 ,8106). A contagem de leucócitos totais (p= 0,0207) e linfócitos totais (p= 0,0032) apresentou diferenças estatisticamente significativas. Nas demais células as contagens não apresentaram diferença estatística significativa (p>0,05). A solução de Hev b 13 pode induzir a redução da amplificação da cascata celular imunológica, reduzindo a produção de leucócitos e linfócitos totais, modulando a resposta imunológica. O experimento realizado induziu síntese de interleucina 10 (IL-10) e Fator de necrose tumoral (TNF). Os ratos que receberam Hev b 13, apresentaram no tecido pulmonar menor envolvimento de células inflamatórias.
Reis, Guilherme de Oliveira. "Study of the mechanism of acid coagulation of Hevea latex and of the rheological properties of resulting gels". Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS227/document.
Texto completo da fonteNatural rubber latex is mainly composed by rubber particles whose core is made of cis-1,4-polyisoprene and the shell of non-isoprene compounds. It stability in the tree is provided by the negative charge of the shell due to the presence of proteins and lipids. Natural rubber latex coagulates after acidification to form a colloidal gel that is the first step of its transformation into natural rubber.In this PhD thesis, we studied this acid-induced aggregation and gelation and the properties of the resulting gels. For this, a commercial natural rubber latex composed by rubber particles (1 µm in diameter), was used. Aggregation was induced by hydrolysis of a compound called glucano-delta-lactone (GDL). The aggregation was followed by different techniques based on light scattering (turbidimetry, DWS, SLS). Gelation was followed in situ by rheology. Then, the rheological properties of colloidal gels formed at pH 4 were characterized in the linear and non-linear regimes.Dependence to the volume fraction and the pH of the onset of aggregation was observed. The non-redispersion of aggregates proves the strong interactions between rubber particles. Three different state behaviors (stable solution, phase separation and gel) can be predicted from a state diagram pH-volume fraction that was established over 5 weeks. The gel state exhibits a fractal structure, characterized by a power law relationship between the elastic modulus G’ and the volume fraction. At high deformations, an irreversible reorganization under stress resulted in an irreversible strain hardening of the material. We observed by rheo-ultrasound that above 50% deformation, an homogenous destructuration occurred in the gel
Frade, Marco Andrey Cipriani. "Úlcera de perna: caracterização clínica e perfil imunohistopatológico da cicatrização na presença da biomembrana de látex natural da seringueira Hevea brasiliensis". Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/17/17138/tde-17042012-215000/.
Texto completo da fonteThe leg ulcer is a disease very frequent in elderly people. Nowadays, there are many kinds of dressing to treat its with different indications, advantage and disadvantage. Their efficacy is not clear yet because to the treatments discontinuous and the costs involved in same situations. The latex biomembrane from rubber tree Hevea brasiliensis (NLB) showed an improvement of the healing process to treat leg ulcer, observed by the clinical and the immune histopathological aspects. To verify whether the NLB could be associated with an increased healing we selected 21 leg ulcer patients to be submitted to the topical treatment. These patients were divided into two groups. In the first group 14 randomized patients were treated with latex biomembrane and in the other group 07 patients were treated with topical ointment of cloranfenicol and proteolitic enzymes with the objectives to analyze and to compare the histopathological and immunohistochemical alterations related to the different treatments. All the patients were submitted at least to two biopsies; before the treatment and the 30th day of the treatment. The biopsies specimens were divided into two parts; one of them for the histopathological study and the other was frozen for the immunohistochemical analysis. The results showed that the biomembrane is very easy, practical and cheap leg ulcer topical treatment. Additionally, the NLB induces to a clinical and hystopathological differentiation of the cicatrization tissue with increased detection of growth factors as VEGF (vascular endothelial growth factor) and TGF-1(transforming growth factor1), associated to a reduction of iNOS (induced oxide nitric sintase) expression when compared to the control treatment. The global analyze of the data suggest that the biomembrane of natural latex led to cicatricial tissue organization and a higher production of cellular growth factors. So, this treatment can characterize as a good therapeutic option for leg ulcers due the facility of the application, low costs and high potentiality to induce of the cicatrization.
Zhang, Yi. "Identification des gènes impliqués dans la production et la détoxication des espèces activées de l'oxygène chez Hevea brasiliensis et leur caractérisation dans le latex". Thesis, Montpellier, 2018. http://www.theses.fr/2018MONTG004/document.
Texto completo da fonteHevea brasiliensis, a tropical tree, is the main commercial source of nature rubber. The rubber biosynthesis occurs in specialized latex cells of rubber tree. Up 90% dry weight of latex is nature rubber. The milky latex flows out from cut latex cells by tapping rubber tree trunk bark. Rubber exploitation by tapping every several days is very stressful for the bark of rubber tree. To stimulate latex production, ethylene releaser is applied during rubber exploitation in some cases. The stress is increased after hormone stimulation. Reactive oxygen species (ROS) is generated when plant suffers stresses from environment and harvesting activity. Over a certain limit of stress, ROS bursting is motivated in latex cell. A lots of the evidences showed that the ROS lead to the peroxidatic degradation of the unsaturated lipids of the membrane and then to destabilisation and lysis of the organelles. Lysis of the lutoids results in liberation of coagulating factors into latex and coagulation in situ of rubber particles in stressed trees. This serious physiology syndrome is tapping panel dryness (TPD) which is one of main factor limiting rubber production.This PhD aims at identifying ROS production and scavenging genes and their characterizations in latex cell. Firstly, we made a comprehensive bibliography study on ROS production and scavenging genes both in rubber tree and model plant. The NADPH oxidase was considered as the main source of ROS in the stressed trees. ROS scavenging enzymes and antioxidants constituted the ROS scavenging systems in latex. Secondly, based on a genome-wide analysis, 407 genes involved in ROS production and scavenging were identified. Thirdly, based on a transcriptome analysis, 164 redox-related genes were detected expressing in latex of clone SP217 and 161 genes expressing in latex of clone PB260. Fourthly, based on small RNA and degradome analysis, 13 genes were shown to be targeted by 11 microRNAs and 15 genes by 16 phased siRNA in latex. Lastly, this study illustrated specific regulation systems of ROS production and scavenging in latex. HbRBOH2 was identified as the main source gene of ROS in latex. HbCuZnSOD4 might be the most important ROS scavenging gene to detoxify the ROS in latex of TPD tolerant tree
Honorato, Sara Braga. "Antioxidant effect of components of the latex from seringueira (Hevea brasiliensis)and mangabeira(Hancoria speciosa)on thermo-oxidative degradatiion of synthesic Poly (1,4-cis-isoprene". Universidade Federal do CearÃ, 2005. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=1429.
Texto completo da fonteFundaÃÃo de Amparo à Pesquisa do Estado do CearÃ
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico
This work is divided into two parts: The first is associated with the isolation of non-isoprenic components from the natural rubber (NR) latex from seringueira (Hevea brasiliensis) and mangabeira (Hancornia speciosa) by centrifugation. In the first centrifugation the phase serum was isolated (MAT 1). The rubber phase was treated with the surfactant sodium dodecyl sulphate (SDS) and isolated after the third centrifugation (MAT 2). The other materials tested in the synthetic rubber (PIS) were CENT 1, CENT 2 and the NR extract. These were kindly provided by Prof Jean Marinho from UNESP. The second part is associated with the possible antioxidant effect of the isolated latex components on the thermo-oxidative degradation of synthetic poly(1,4-cis-isoprene) carried out via infrared (FT-IR), thermogravimetric analysis (TG) and Nuclear Magnetic Resonance (RMN). It was observed that, from the substances obtained from the purification of the latex and tested on synthetic PIS, both MAT 1 and CENT 1 have pro-oxidant effects. The remain can be ordered in the following sequence in regards to their antioxidant capabilities: PIS + MAT 2 > PIS + NR EXTRACT > PIS + CENT 2 The calculation of the activation energy of the thermal degradation of PIS in synthetic air containing 2.0% of MAT 2 confirms that the stabilizer effect of PIS increases with the increase of this material, as all Ea of pure polymer are inferior to that of the doped sample. The NMR spectra for MAT 2 showed, in addition to the characteristic bands of cis-1,4-polyisoprene, also bands associated with fatty acids and/or SDS. The spectra of NR extract showed bands that are characteristic of oligosaccharides and minoritary cis-1,4-polyisoprene.
O presente trabalho à dividido em duas partes: A primeira està relacionada com o isolamento dos componentes nÃo-isoprÃnicos do lÃtex da borracha natural (BN) da seringueira (Hevea brasiliensis) e mangabeira (Hancornia speciosa) por centrifugaÃÃo. Na primeira centrifugaÃÃo foi isolada a fase serum (MAT 1). A fase borracha foi tratada com o surfactante dodecil sulfato de sÃdio (SDS) e isolada apÃs a terceira centrifugaÃÃo, (MAT 2). Os outros materiais testados à borracha sintÃtica (PIS) foram o CENT 1, CENT 2 e o extrato de BN, os quais foram gentilmente cedidos pelo Prof. Jean Marinho da UNESP. A segunda parte refere-se ao possÃvel efeito antioxidante dos componentes do lÃtex isolados sobre a degradaÃÃo termo-oxidativa do poli (1,4-cis-isopreno) sintÃtico realizada atravÃs das tÃcnicas de Infravermelho (FT-IR), AnÃlise TermogravimÃtrica (TG) e RessonÃncia MagnÃtica Nuclear (RMN). Foi observado que, das substÃncias obtidas da purificaÃÃo do lÃtex e testadas no PIS sintÃtico, tanto o MAT 1 quanto o CENT 1 tÃm efeitos prÃ-oxidantes. Os demais podem ser ordenados na seguinte seqÃÃncia quanto ao poder antioxidante: PIS + MAT 2 > PIS + EXTRATO DE BN > PIS + CENT 2 O cÃlculo da energia de ativaÃÃo (Ea) da degradaÃÃo tÃrmica do PIS em ar sintÃtico contendo 2,0% do MAT 2 confirma que o acrÃscimo desse material exerce um efeito estabilizante ao PIS, pois todas as Ea do polÃmero puro sÃo inferiores à da amostra dopada. Os espectros de RessonÃncia MagnÃtica Nuclear para o MAT 2 exibiram, alÃm de sinais caracterÃsticos do cis-1,4-poliisopreno, sinais relativos a Ãcidos graxos e/ou SDS, enquanto que os espectros do Extrato de BN exibiram sinais caracterÃsticos de oligossacarÃdeos e poli (1,4-cis-isopreno) como componentes minoritÃrios.
Thepchalerm, Chalao. "Influence of Hevea brasiliensis latex compartments on the storage hardening of natural rubber : study of the mesostructure by AF4-MALS and of the mineral element composition by ICP-MS". Thesis, Montpellier, SupAgro, 2014. http://www.theses.fr/2014NSAM0016/document.
Texto completo da fonteThe aim of the present work was to study the influence of two Hevea brasiliensis latex compartments, namely lutoids and C-serum, on the storage hardening and on mesostructure of natural rubber (NR). A special focus was done on the involvement of mineral components of latex. The NR mesostructure was studied by asymmetrical flow field-flow fractionation coupled to a multiangular light scattering detector (AF4-MALS) and by size exclusion chromatography equipped with a multiangular light scattering detector (SEC-MALS). Inductively coupled plasma mass spectrometry (ICP-MS) was used to determine the mineral element composition of NR.As AF4-MALS and ICP-MS were never used for NR analysis, the methodologies were developed. For AF4-MALS, the best separation between the two main populations, namely isolated polyisoprene chains (random coil) and microaggregates (Gel<1µ) was given by a linear decrease, rather than exponential, of the cross-flow. For ICP-MS, the optimizations were in terms of amount of NR to be sampled, ash solubilisation methodology, ash solutions concentrations and m/z interference management. All elements, except sulfur, were determined using a mixture H2/He as collision-reaction gas (CCT H2/He mode). Sulfur content was determined through the m/z equal to 48 (32S16O+) in the CCT O2 mode.The different compartments of the whole field latex (cream, skim, C-serum and lutoids) were separated by high speed centrifugation. The mesostructure evolution of films obtained from these 3 lattices; whole field latex (FL), cream latex (CL), and skim latex (SK), by a slow structuring process (samples stored at room temperature in the laboratory for 3 months) was followed by SEC-MALS. As it was observed that the skim was not sensitive to the slow structuring, the centrifugation steps were reduced.Lutoid stability was studied by a qualitative parameter (visual lutoid status after centrifugation) and a quantitative parameter (bursting index or BI). Although the two methods could not provide strictly correlated results, BI can be a good indicator of lutoid stability. For the FL samples, a good correlation between the lutoid stability and storage hardening (ΔP) was observed. To determine if some compounds of C-serum are also involved in the storage hardening, additional experiments were done adding variable quantities of C-serum or lutoids to purified rubber particles. The storage hardening (ΔP) increased by the increase of both C-serum and lutoid quantities.The mesostructure of films and air dried sheet (ADS) made from FL and CL lattices (obtained from reduced centrifugation process) were analyzed by SEC-MALS and AF4-MALS. Concerning the ADS samples, whatever the technique used, FL samples exhibited a higher Mw, Mn, and Gel>1µ than CL samples. This difference between FL and CL samples was not observed for film samples. The microaggregates (Gel<1µ) were presented in all samples but the FL samples had more compact microaggregates, with a much higher Mw than the CL samples. Moreover, AF4 showed that the structure of microaggregates was very different between ADS and film samples. The Mw of microaggregates of ADS was 2 to 4 times higher than that of films. The mineral elements were determined only on samples from ADS (FL and CL). The main elements in NR were K, P, Mg, and S, in decreasing order. The purification of rubber particles affected the decrease in the element contents. During the storage of the latex at room temperature, only calcium content decreased, for both FL and CL samples
Araújo, Marcos Miranda de. "Efeitos da utilização de insulina e de um implante transitório de biomembrana de látex natural, derivado da seringueira Hevea brasiliensis, em um modelo experimental de perfuração traumática de membrana timpânica". Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/17/17150/tde-20012013-151842/.
Texto completo da fonteIn recent years, there has been a tendency to search for regulatory substances that can optimize the healing process of perforated tympanic membranes (TMs). Objectives: To determine the effects of using topical insulin and natural latex biomembrane, alone or in combination, in the healing process of traumatic perforations of TMs. Methods: TMs of 61 Wistar rats were perforated in two sections, anterior and posterior to the malleus. The rats were divided into 4 groups: Control, Insulin, Latex, and Insulin+Latex. The Insulin group was treated with topical regular insulin. The Latex group was treated with natural latex biomembrane. The Insulin+Latex group was treated with a combination of insulin plus latex biomembrane. The TMs were histologically examined 3, 5, and 7 days post-perforation through morphometric analysis of the thickness of the epithelial, fibrous, and mucosal layers; size of the perforation; cross sectional area of the TM; semiquantitative and qualitative evaluation of the collagen production by polarization microscopy, and immunohistochemical evaluation of epithelial cells, myofibroblasts, and vascularization markers. Results: Insulin and latex biomembrane accelerated the healing process of the perforated TMs (p<0.01); stimulated early thickening of the outer epithelial layer (p<0.01); promoted premature increase in the thickness of the fibrous layer (p<0.01); contributed to a larger identification of anti-pankeratin antibody as epithelial marker (p<0.05); increased labeling of anti-alpha smooth muscle actin antibody (p<0.05), indicating greater proliferation of myofibroblasts. When insulin was used alone, it resulted in greater formation of collagen tissue (p<0.05), with thicker and better-organized collagen fibers (p<0.05). Conclusion: Insulin and natural latex biomembrane, used alone or in combination, accelerated the healing process of traumatic perforations of TMs.