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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Estaurosporinas de Eudistoma vannamei: QuÃmica e Bioatividade / Staurosporines from Eudistoma vannamei: Chemistry and Bioactivity.

Paula Christine Jimenez 15 July 2009 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Eudistoma vannamei (Millar, 1977) à uma ascÃdia endÃmica do litoral do Nordeste brasileiro, largamente encontrado nas praias rochosas do estado do CearÃ. Previamente, o extrato bruto apresentou um interessante perfil em termos de bioatividade. O fracionamento bioguiado identificou uma mistura 1:1 altamente citotÃxica, contendo dois derivados inÃditos de estaurosporina, 2-hidroxi-7-oxoestaurosporina (I) e 3-hidroxi-7-oxoestaurosporina (II). IC50 para I/II e estaurosporina (STP) foram obtidas apÃs 72h de incubaÃÃo com diversas linhagens de cÃlulas tumorais, utilizando-se o ensaio do MTT, e em linfÃcitos humanos normais, atravÃs do ensaio de AlamarBlue. I/II superou a citotoxicidade de STP em 7 vezes, em mÃdia, para as cÃlulas tumorais, ao passo que mostrou-se tÃo ativa quanto frente Ãs cÃlulas normais. Uma anÃlise cinÃtica sobre a progressÃo de ciclo celular, ativaÃÃo de resposta a dano e vias de reparo de DNA, e induÃÃo de apoptose de cÃlulas HL-60 (leucemia) foi conduzida com 40 ou 80ng/mL I/II e acessada por citometria de fluxo e western blotting. Estudos de ciclo celular indicaram que I/II (40ng/mL) induz bloqueio de ciclo celular em G2/M e que este efeito prossegue irreversÃvel mediante a remoÃÃo do estÃmulo. STP (200ng/mL) induziu o bloqueio quase que completo em G2/M apÃs 24h de incubaÃÃo, enquanto perÃodos mais longos de incubaÃÃo provocam um aumento substancial de cÃlulas poliplÃides. A expressÃo de proteÃnas envolvidas no controle do ciclo celular (Cdk1, Cdk2, ciclina A e ciclina B1), associada à observaÃÃo morfolÃgica de cÃlulas tratadas com 40ng/mL I/II e coradas com H/E em lÃminas de vidro sugere que o bloqueio està ocorrendo, de fato, na fase G2. O bloqueio em G2 foi parcamente observado em cÃlulas tratadas com 80ng/mL I/II, conquanto caracterÃsticas apoptÃticas fizeram-se deveras evidentes. A avaliaÃÃo de dano à fita dupla de DNA atravÃs do teste do cometa neutro indica a induÃÃo apenas de baixo nÃvel de dano de DNA em cÃlulas tratadas com 40ng/mL I/II por 24, 48 ou 72h. Entretanto, cÃlulas tratadas com 80ng/mL I/II exibiram nÃveis mais elevados de dano. A expressÃo de proteÃnas relacionadas a dano de DNA (ATM e H2A.X) deu-se numa forma tempo- e concentraÃÃo-dependente, enquanto o bloqueio de ciclo e os marcadores de reparo (Chk1, Cdc25C, BRCA1) foram ativados, predominantemente, em cÃlulas tratadas com 40ng/mL I/II. Inversamente, a externalizaÃÃo de PS e a ativaÃÃo das caspases efetoras 3 e 7 e de PARP mostraram-se altamente expressos em cÃlulas tratadas com 80ng/mL I/II mostrou um claro efeito citostÃtico em cÃlulas HL-60 na menor concentraÃÃo testada, evidenciado pelo persistente bloqueio de ciclo celular e baixo dano em DNA; e um objetivo efeito citotÃxico na concentraÃÃo maior, motivado pelo extensivo dano em DNA e induÃÃo de apoptose. / Eudistoma vannamei Millar, 1977 is an endemic tunicate from the northeastern Brazilian coast, widely distributed over the rocky beaches of Cearà State. Previously, the crude extract showed an interesting bioactivity profile. Bioassay-guided fractionation yielded a highly cytotoxic 1:1 mixture identified as two novel staurosporine derivatives, 2-hydroxy-7-oxostaurosporine (I) and 3-hydroxy-7-oxostaurosporine (II). IC50 for I/II and staurosporine (STP) were obtained after 72h incubation with various tumor cell lines using the MTT assay and in normal human lymphocytes, by the AlamarBlue assay, where I/II outperformed STP in a 7-fold average. On normal cells, I/II showed to be equally effective as STP and, thus, showed a 25-fold average selectivity towards tumor cells. A kinetic analysis on cell cycle progression, activation of DNA damage and repair pathways and apoptosis induction of HL-60 cells (leukemia), was carried out with 40 or 80ng/mL I/II and accessed by flow cytometry and western blotting. Cell cycle studies indicated that I/II induces a G2-M arrest (at 40ng/mL, 45, 63 and 94% of arrested cells after 24, 48 and 72h treatment, respectively, against 9, 10 and 13% for the non-treated culture). Moreover, 24h-G2/M arrest is sustained and irreversible following removal of stimuli. STP induces 83% G2/M arrest at 200ng/mL after 24h incubation, whilst longer incubation periods provoke a substantial increase in polyploidy. Expression-rate of cell cycle related proteins (Cdk1, Cdk2, cyclin A and cyclin B1) paired with morphological observation of 40ng/mL I/II-treated H/E-stained cells placed on glass slides suggest that arrest is actually occurring at the G2 phase. G2 arrest is merely seen in 80ng/mL I/II-treated cells, while apoptotic features were quite evident. Double-strand breaks evaluated by the neutral comet assay indicates only low scored DNA damage against 24, 48 or 72h 40ng/mL I/II treated cells. However, 80ng/mL I/II-treated cells exhibited higher scored damage. DNA damage proteins (ATM and H2A.X) were expressed in a time- and concentration-dependent manner; while, cycle arrest and repair markers (Chk1, Cdc25C, BRCA1) were activated mostly on 40ng/mL I/II-treated cells. Conversely, PS externalization and activation of effector caspases 3 and 7 and PARP were highly blotted mostly for 80ng/mL I/II-treated cells. I/II induced a clear cytostatic effect on HL-60 cells at the lower concentration, distinguished by persistent cell cycle arrest and low DNA damage; and an objective cytotoxic effect at the higher concentration, motivated by extensive DNA damage and induction of apoptosis.
52

Bioatividade de vidros contendo nióbio : estudo experimental in vivo / Bioactivity of glasses composed by niobium : an experimental in vivo study

Souza, Lucas Pereira Lopes de, 1989- 25 August 2018 (has links)
Orientador: José Angelo Camilli / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-25T16:59:30Z (GMT). No. of bitstreams: 1 Souza_LucasPereiraLopesde_M.pdf: 1756933 bytes, checksum: 1c3778ee02f4dd8104d6a216a95db04b (MD5) Previous issue date: 2014 / Resumo: Alguns estudos mostram que a introdução do óxido de nióbio (Nb2O5) na composição do Bioglass® poderia ser uma solução para melhorar sua resistência mecânica, mantendo sua biocompatibilidade e bioatividade, porém, apesar da melhora na resistência mecânica causada pela adição deste óxido ser bem documentada na literatura, suas propriedades bioativas ainda são pouco conhecidas. Neste contexto, o objetivo do presente estudo foi avaliar experimentalmente as propriedades bioativas do óxido de nióbio em ratos albinos (Rattus norvegius) da linhagem Wistar. Para isso, bastões vítreos compostos por diferentes concentrações do Nb2O5 foram implantados na tíbia de ratos. Além disso, cada vidro teste, na forma de pó, foi implantado no músculo de ratos para análise de suas propriedades pró-angiogênicas, usando o Bioglass 45S5 (Bioglass®) como controle. As eutanásias foram realizadas 14 e 28 dias pós-cirurgias. Lâminas histológicas de cortes transversais das tíbias foram coradas a H&E para mensuração da área de osso subperiostal existente na cortical adjacente ao implante e a quantidade de osso esponjoso formado ao redor do bastão vítreo nos grupos de 14 dias, bem como da espessura da lâmina óssea formada ao redor do bastão nos grupos de 28 dias. Foi ainda realizada marcação imuno-histoquímica e a razão entre a área total do implante em mm2 e o número total de vasos sanguíneos contados manualmente num aumento de 400x para verificação a capacidade do material de estimular a angiogênese. A avaliação histológica revelou a ausência total de inflamação tanto após 14 quanto após 28 dias de implante. Os resultados das comparações entre as áreas de osso subperiostal dos grupos após 14 e 28 dias (feitas através de um teste ANOVA com post hoc tukey) e da quantidade de osso esponjoso formado ao redor do implante nos grupos 14 dias (feitas através do teste Kruskal-Wallis com Mann-Whitney como post hoc) mostraram que o BGPN1.3 apresentou maior capacidade de induzir a formação óssea do que o grupo controle, já com relação ao número de vasos sanguíneos e espessura da lâmina óssea formada ao redor do implante todos os grupos apresentaram resultado semelhantes. Assim, se concluiu que o BGPN1.3 trata-se de um material inovador por ser biocompatível, apresentar propriedade osteoindutiva superior e capacidade pró-angiogênica semelhante ao Bioglass® / Abstract: Some studies show that the introduction of niobium oxide (Nb2O5) into Bioglass® composition could be a solution to improve its mechanical strength while maintaining its biocompatibility and bioactivity, but in spite of improvement in resistance caused by addition of the oxide is well documented in the literature, their bioactive properties are still poorly known. In this context, the aim of this study was to experimentally evaluate the bioactive properties of niobium oxide in albino rats (Rattus norvegius). For this, glassy rods composed of different concentrations of Nb2O5 were implanted in the rats¿ tibia. In addition, each test glass in powder form was implanted into the muscle of mouse for analysis of their pro-angiogenic properties using 45S5 Bioglass (Bioglass®) as control. Euthanasia were performed 14 and 28 days post-surgery. Histological slides of cross sections of tibiae were H & E stained for measuring the area of existing subperiosteal bone in adjacent to the implant and the amount of cancellous bone formed around the vitreous rod after 14 days pos-surgery as well as the thickness of the formed bone sheet around the rod in groups of 28 days. It was also performed immunohistochemical staining to calculate the ratio between the total area in mm2 of the implant and the total number of blood vessels, counted manually using a magnification of 400x, to check the capacity of the material to stimulate angiogenesis. Histological evaluation revealed the complete absence of inflammation after both 14 and after 28 days of implantation. The results of the comparisons between the areas of subperiosteal bone of groups after 14 and 28 days (made by an ANOVA with Tukey post hoc test) and the amount of cancellous bone formation around the implant in the groups 14 days (done by Kruskal -Wallis with Mann-Whitney post hoc) revealed that BGPN1.3 showed greater ability to induce bone formation than the control group, when compared the number of blood vessels and thickness of the blade bone formed around the implant all groups showed similar results. Thus, we concluded that BGPN1.3 is an innovative material to be biocompatible and display better osteoinductive property than Bioglass® showing similar pro-angiogenic capacity / Mestrado / Anatomia / Mestre em Biologia Celular e Estrutural
53

Síntese e caracterização de uma nova pasta endodôntica com sistemas carreadores de fármacos

Cuppini, Marla January 2017 (has links)
O objetivo do presente estudo foi sintetizar e caracterizar um material reparador para uso endodôntico com propriedades anti-inflamatória, antimicrobiana e remineralizante. A pasta experimental tem como propósito ser um sistema carreador de fármacos para regiões de difícil acesso em Odontologia. A apresentação do material é em forma de pó:líquido. No pó se encontra α-fosfato tricálcico, tungstato de cálcio e microesferas de amoxicilina (AMX-MS), já no líquido estão contidas nanocápsulas de indometacina (IndOHNC). A pasta experimental foi testada em relação a suas características físicoquímicas e biológicas. As AMX-MS obtiveram tamanho de 1,604 μm ± 0,08, forma esférica confirmada por MEV e teor da droga foi 1,63 mg g-1. As IndOHNC obtiveram tamanho de 162 ± 7,5 nm e forma esférica confirmada por MET. O teor do fármaco foi de 1 mg mL-1 ± 0,02. O escoamento da pasta foi de 18.56 ± 0.29, a espessura de película obtida foi 33 μm e radiopacidade de 1,81 mmAl. A pasta experimental demonstrou atividade antibacteriana contra o Enterococcus faecalis. A maior concentração de pasta experimental apresentou o maior valor em relação à viabilidade celular, com 187,03% no teste SRB. A atividade da enzima fosfatase alcalina e a formação de nódulos mineralizados obtiveram um gradual aumento em função do tempo. A migração celular demonstrou fechamento da ferida, e a pasta experimental foi capaz de acelerar o processo (p<0.05). Em conclusão, a pasta experimental demonstrou propriedades físico químicas e biológicas confiáveis, podendo ser um material promissor para o reparo da região periapical. / The aim of this study was to synthesize and characterize a new reparative material with anti-inflammatory, antimicrobial and remineralizing properties. The reparative material was developed to be a drug delivery system for regions with difficult access in Dentistry. The formulation is presented in powder/liquid. The powder is composed of α-tricalcium phosphate, calcium tungstate and amoxicillin microspheres (AMX-MS). The liquid is composed of nanocapsules containing indomethacin (IndOH-NC). The physicochemical and biological properties of the experimental endodontic paste were evaluated. The AMX-MS obtained a mean size of 1.604 μm ± 0.08, spherical shape and the encapsulation capacity was 1.63 mg g-1. IndOH-NCs obtained a mean size of 162 ± 7.5 nm and spherical shape confirm by MET. The content of the encapsulated drug was 1 mg mL-1 ± 0.02. The experimental paste flow was 18.56 ± 0.29 mm, mean film thickness was 33 μm and radiopacity equivalent to 1.81 mmAl. The experimental paste showed antibacterial activity against Enterococcus faecalis. The highest concentration of experimental paste presented the highest value in cell viability (187.03% in SRB test). The activity of the phosphatase alkaline enzyme and the formation of mineralized nodules showed a gradual increase as a function of time. Cell proliferation showed continuous wound closure, and the experimental paste was able to accelerate the process (p<0.05). In conclusion, the experimental paste demonstrated reliable physicochemical and biological properties, and it could be a promising material for periapical region repair.
54

In vivo and in vitro bioactivity of a "precursor of apatite" treatment on polyetheretherketone / 「アパタイト前駆体」処理を施したポリエーテルエーテルケトンのin vivoおよびin vitroにおける生体活性

Masamoto, Kazutaka 23 March 2020 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第22367号 / 医博第4608号 / 新制||医||1043(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 戸口田 淳也, 教授 妻木 範行, 教授 安達 泰治 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM
55

Bio-prospecting of Plants and Marine Organisms in Saudi Arabia for New Potential Bioactivity

Hajjar, Dina A. 08 December 2016 (has links)
The natural resources offer a unique opportunity for the discovery of active compounds, due to the complexity and biodiversity of their chemical structures. Natural resources have been used as medicines throughout human history. Saudi Arabia’s natural resources, for instance its terrestrial medicinal plants and the Red Sea sponges, have not been extensively investigated with regard to their biological activities. To better identify the diversity of compounds with bioactive potential, new techniques are also necessary in order to improve the drug discovery path. This study comprises three sections. The first section examines Juniperus phoenicea (Arar), Anastatica hierochuntica (Kaff Maryam) and Citrullus colocynthis (Hanzal); these herbal plants were screened for potential bioactivity using a newly developed pipeline based on a high-content screening technique. We report a new cell-based high-throughput phenotypic screening for the bio-prospecting of unknown natural products from Saudi Arabian plants, in order to reveal their biological activities. The second section investigates Avicennia marina plants, screened for reverse transcriptase anti-HIV bioactivity using biochemical assay. Image-based high-content screening with a set of cellular stains was used to investigate the phenotypic results of toxicity and cell cycle arrest. The third section considers the isolation of Actinomycetes from Red Sea Sponges. Actinomycetes bacterial isolates were tested for bioactivity against West Nile Virus NS3 Protease. Analytical chemical techniques such as liquid chromatography–mass spectrometry (LC-MS), gas chromatography–mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) were used to gain more understanding of the possible chemical compounds responsible for this bioactivity. Overall, the aim of this work is to investigate the potential bioactive effect of several Saudi Arabian plants and Red Sea sponges against cancer cells and viral infections. Our study demonstrates the efficiency of the newly developed pipeline using cell-based phenotypic screening. Anti-cancer potential activity was detected in Juniperus phoenicea. Bioactive potential against the reverse transcriptase enzyme of HIV virus was confirmed in Avicennia marina leaves. The organic extracts of Actinomycetes bacterial isolates were found active against West Nile Virus NS3 Protease. Here, promising starting point for the potential of drug discovery of plants and marine organism of Saudi Arabia.
56

Syntéza pěnové biokeramiky pro potenciálně lékařské aplikace / Synthesis of foamed bioceramics for potential medical applications

Doboš, Petr January 2012 (has links)
Cílem práce byla příprava porézních vzorků HAP pro potenciálně medicínské aplikace. HAP byl připraven metodou sol-gel a precipitační. Vzorky HAP byly podrobeny analýze FTIR, XRD, SEM. Takto připravený HAP byl napěněn pomocí houbové metody s jasně definovanými póry a pomocí polymerního a skleněného expanzelu s různou distribucí a velikostí pórů. U výsledných napěněných vzorků byla vyhodnocena mikrostruktura a povrchová analýza pomocí SEM, zjištěna porozita pomocí Hg porozimetru a sledována bioaktivita in vitro v SBF. Byly zjištěny jasně definované makro, mezo a mikro póry při různé distribuci. U houbové metody pomocí sol-gel došlo k vytvoření jasně definovaných a pravidelných pórů s monodisperzní porozitou. Dominantní velikost póru byla stanovena v rozmezí 1–5 µm. Celková porozita byla stanovena na 63,5 % s celkovým povrchem 3,048 1 m/g. Precipitační metodou s polymerním expanzelem došlo k polydisperznímu rozložení pórů s třemi hlavními fázemi v rozmezí: 50–100 µm, 5–10 µm a 0,5–1 µm. Celková porozita byla stanovena na 67,6 % s celkovým povrchem 19,090 3 m/g. Bioaktivita výsledných napěněných vzorků in vitro byla sledována po dobu 7 dnů v připraveném SBF. Při napěnění sol-gel houbovou metodou nevznikla výsledná bioaktivní vrstva. U precipitační metody napěněné pomocí polymerního expanzelu vznikla nepravidelná bioaktivní vrstva. Výsledky byly naměřeny pomocí SEM analýzy.
57

Syntéza a vlastnosti biokompozitních materiálů s potenciálním využitím v medicíně / The Synthesis and Characterisation of Biocomposite Materials for Potential Application in Medicine

Balgová, Zuzana January 2014 (has links)
Dizertační práce se zabývala syntézou a studiem kompozitních materiálů pro potenciální lékařské využití. Teoretická část je zaměřena na biomateriály, zejména na kompozity složené z polyvinylalkoholu a hydroxyapatitu(PVA/HA). Byly připraveny kompozitní membrány složené z polyvinylalkoholu s různým hmotnostním zastoupením hydroxyapatitu - 0%, 10%, 20%, 30%, 40% a 50%. Hydroxyapatit (HA) byl připraven srážecí metodou z hydrogenfosforečnanu amonného a tetrahydrátu dusičnanu vápenatého ve vodném alkalickém prostředí. Vzniklá suspenze se smísila s roztokem polyvinylalkoholu, který byl připraven rozpuštěním ve vodě o teplotě 85° C. Jednotlivé směsi byly odlity do formy a sušeny po dobu 7 dní při teplotě 30 ° C, vzniklé 0,5 mm tenké membrány byly analyzovány ATR-FTIR spektroskopií k identifikaci funkčních skupin v kompozitu, dále byla provedena XRD analýza. Zkouška tahem a TGA měření byly realizovány k určení vlivu HA na mechanické vlastnosti, respektive změnu tepelné odolnosti kompozitů ve srovnání s čistým PVA. Byla provedena zkouška bioaktivity v simulovaném krevním roztoku (SBF) po dobu 2h, 7 a 28 dnů. SEM byla použita k charakterizaci povrchové mikrostruktury biocompositních membrán před a po ponoření do SBF. Na povrchu testovaných membrán vznikla vrstva apatitu, která je charakteristická pro bioaktivní materiály. Bylo zjištěno, že s rostoucím množstvím HA částic docházelo ke vzniku aglomerátů v kompozitu, které vznikly mimo jiné jako důsledek růstu krystalů HA během sušení membrán. Bioaktivita rostla s delším působením SBF na vzorky.
58

Bioactivity and chromatographic profiles of the selected medicinal plants against candida albicans

Mulaudzi, Takalani Millicent 17 July 2015 (has links)
MSc (Botany) / Department of Botany
59

Particalized Eggshell Membrane (PEM) for Biomedical Applications

Wu, Ling 03 February 2021 (has links)
Eggshell membrane (ESM) provides a physical and bioactive barrier to protect the developing embryo. Proteomics and bioinformatics analyses have revealed that the collagen-rich ESM is composed of >500 proteins with multiple functionalities. The goal of this study was to produce novel particalized ESM (PEM) with enhanced bioactivities for focused applications on positive skin health. A novel top-down method was developed to produce the PEM from table eggs, in a submicron size range. PEM exhibited dose- and size-dependent antimicrobial activity against Gram-positive Staphylococcus aureus (S. aureus), and Gram-negative Pseudomonas aeruginosa (P. aeruginosa) and Escherichia coli (E. coli) species. A dose-dependent anti-inflammatory activity for PEM was observed in an in vitro model but no significant difference between two finest sizes. Additionally, the antioxidant activity of PEM was significantly improved by optimized chemical hydrolysis with size-dependent activity. Taken together, the eco-friendly PEM has great potential as a novel topical ingredient for cosmetics/ skincare applications.
60

Caenorhabditis elegans as a whole organism screening system for isoquinoline alkaloid bioactivities / 個体の線虫を用いたイソキノリンアルカロイド生理活性スクリーニングシステムに関する研究

Chow, Yit Lai 24 March 2014 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(生命科学) / 甲第18421号 / 生博第301号 / 新制||生||40(附属図書館) / 31279 / 京都大学大学院生命科学研究科統合生命科学専攻 / (主査)教授 佐藤 文彦, 教授 永尾 雅哉, 教授 福澤 秀哉 / 学位規則第4条第1項該当 / Doctor of Philosophy in Life Sciences / Kyoto University / DFAM

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