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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.
11

Assessment of embryotoxicity of the antiandrogenic drugs flutamide and bicalutamide in zebrafish (Danio rerio)

Holmlund, Josefin January 2020 (has links)
Introduction: Prostate cancer is the most common type of cancer in Sweden and is often treated using antiandrogenic drug therapy. Two substances belonging to this class of pharmaceuticals are bicalutamide and flutamide. After excretion from the human body, the drug molecules enter the wastewater treatment plant (WWTP). The WWTPs are not effective enough to completely remove pharmaceutical residues, why presence of both bicalutamide and flutamide can be detected in WWTP effluent water. Previous findings: Antiandrogens have been reported to affect reproduction in adult fish, but studies regarding possible effects on the embryonic development of fish are few. Aim: The present study sought to investigate if exposure to bicalutamide or flutamide cause toxicity in the early developmental stages of zebrafish embryos, and whether negative effects occur within concentrations relevant to measured environmental levels. Method: A modified OECD FET-test was used, where additional sublethal endpoints were included and the time period for assessment extended to 144 hours post fertilization (hpf). In addition, a locomotor activity assay was performed at 144 hpf in order to observe any sub-lethal swimming behavioral effects. Results: High doses (10 mg/L) of flutamide led to 100% lethality of the zebrafish embryos but the results suggest no acute toxic effects in the high dose treatment group of bicalutamide, or of either flutamide or bicalutamide within in the low (0.1 mg/L) or intermediate (1 mg/L) treatment groups. Neither did the locomotor activity assay result in statistically significant results, although the pattern of swimming activity in the low dose groups suggests that behavioral developmental effects could be present. Conclusions: High doses of flutamide caused mortality of the embryos, but no lethal or sublethal effects were present at environmentally relevant concentrations. The modest outcome of present study however suggests that further investigation of behavioral developmental effects of antiandrogens could be of future relevance. Analysis of the expression of genes related to neuronal growth, memory and other cognitive behaviors associated with behavioral changes, would then be of interest for further studies.
12

Influência do bloqueio androgênico com flutamida no comportamento de dor e expressão de canais de sódio voltagem dependentes, Nav1.7 e Nav1.8, em um modelo de dor pós-operatória em ratos / Influence of androgenic blockade with flutamide on pain behavior and expression of voltage-dependent sodium channels, Nav1.7 and Nav1.8, in a model of postoperative pain in rats

Barbosa Neto, José Osvaldo 18 October 2018 (has links)
Introdução: Estudos experimentais com animais sugerem que a testosterona atua reduzindo a resposta nociceptiva após estímulos inflamatórios e neuropáticos, porém, o mecanismo pela qual este hormônio atua ainda não foi completamente esclarecido. O objetivo deste estudo é avaliar se o bloqueio androgênico com flutamida promove aumento da nocicepção, e ainda, investigar se esta modulação do comportamento doloroso é decorrente de aumento da expressão de canais de sódio voltagemdependente Nav1.7 e Nav1.8 no gânglio da raiz dorsal de ratos após incisão plantar. Método: Os animais estudados foram divididos em um grupo que recebeu flutamida por via subcutânea, e em um grupo controle que recebeu apenas o veículo como placebo. Após o período de indução, foram submetidos a um modelo de incisão plantar, e posteriormente submetidos à avaliação comportamental nos tempos préoperatório, 2 horas após a incisão, 1º, 2º, 3º e 7º dias de pós-operatório. O teste de von Frey foi utilizado para testar o limiar de retirada da pata, e a dor espontânea foi determinada pelo teste da proteção da pata. A expressão dos canais de sódio foi avaliada através da realização de reação de cadeia de polimerase quantitativa em tempo real para os canais Nav1.7 e Nav1.8 em amostra do gânglio da raiz dorsal correspondente à pata operada. Resultados: Os animais tratados com flutamida desenvolveram maior resposta a dor, tanto no teste de dor evocada quanto no teste da proteção da pata em todos os momentos estudados. Os grupos apresentaram diferença estatisticamente significante no 1º, 2º, 3º e 7º dias de pós-operatório para o limiar de retirada da pata. No teste da proteção da pata, foram significantes nos tempos 2 horas, 3º e 7º dia de pós-operatório. Não houve diferença entre os grupos estudados para a expressão de Nav1.7 e Nav1.8, para cada tempo. A análise de variância mostrou que a expressão de Nav1.7 variou em função do tempo em ambos os grupos, o que não ocorreu na expressão de Nav1.8. Conclusão: Neste estudo foi possível demonstrar que o bloqueio androgênico provocou a redução do limiar para retirada da pata após o 1º dia de pós-operatório, e ainda um escore acumulado no teste de proteção do membro que foi mais elevado no tempo 2 horas, no 3º e 7º dia de pós-operatório. Estes dados sugerem que os androgênios apresentaram um efeito antinociceptivo após a incisão plantar, e ainda que este efeito foi independente dos canais Nav1.7 e Nav1.8 no gânglio da raiz dorsal / Introduction: Evidence accumulated over the years has placed sex hormones as key factors of the differences found between males and females. Experimental studies with animals suggest that testosterone acts to reduce the nociceptive response after inflammatory and neuropathic stimuli, but the mechanism by which this hormone acts has not yet been fully elucidated. The objective of this study was to evaluate if androgenic blockade with flutamide promotes increased nociception in rats and to investigate whether this modulation of the painful behavior is due to an increase in the expression of voltage-dependent sodium channels Nav1.7 and Nav1.8 in the Dorsal root ganglion of rats submitted to a postoperative pain model. Methods: The animals studied were divided into a group that received flutamide subcutaneously, and in a control group receiving only placebo. After the induction period, the animals were submitted to a model of plantar incision, and then submitted to behavioral evaluation in the preoperative times, 2 hours after incision, 1st PO, 2nd PO, 3rd PO and 7th PO. The animals were submitted to Von Frey\'s test to determine the evoked pain, and the spontaneous pain was determined by the paw protection test (Guarding Pain). The expression of the sodium channels was evaluated by performing real time quantitative polymerase chain reaction for Nav channels in the dorsal root ganglion sample corresponding to the incised hindpaw. Results: Animals treated with flutamide developed greater nociception in both the evoked pain test and the paw protection test at all times studied. Statistically significant differences were found in the times 1st PO, 2nd PO, 3rd PO and 7th PO for the paw withdrawal threshold. Guarding pain test showed significant results at 2 hours, 3rd PO and 7th PO. No difference was found between the studied groups for the expression of Nav1.7 or Nav1.8 at each time point. Variance analysis showed that Nav1.7 expression was dependent on time in both groups, but Nav1.8 expression did not change over time Conclusions: In this study it was possible to demonstrate that flutamide caused a reduction in the paw withdrawal threshold after the 1st postoperative day, and also a guarding pain score that was higher 2 hours after incision, on the 3rd and 7 th day of postoperative. Data presented in this study suggest an antinociceptive effect of androgens after plantar incision that was independent of Nav channels
13

DESENVOLVIMENTO DE UM SIMPLES E NOVO SENSOR PARA FLUTAMIDA À BASE DE NANOTUBOS DE CARBONO OXIDADO E ÓXIDO DE GRAFENO: APLICAÇÃO EM AMOSTRAS DE URINA ARTIFICIAL E FORMULAÇÕES FARMACÊUTICAS / DEVELOPMENT OF A NEW AND SIMPLE SENSOR FOR FLUTAMIDE TO BASE OXIDIZED CARBON NANOTUBES AND GRAPHENE OXIDE: APPLICATION IN ARTIFICIAL URINE SAMPLES AND PHARMACEUTICAL FORMULATIONS

FARIAS, Julianna Santos 06 March 2017 (has links)
Submitted by Maria Aparecida (cidazen@gmail.com) on 2017-04-12T15:30:06Z No. of bitstreams: 1 Juliana Santos Farias.pdf: 1234303 bytes, checksum: 420e49b91acb05fb1346e95075411509 (MD5) / Made available in DSpace on 2017-04-12T15:30:06Z (GMT). No. of bitstreams: 1 Juliana Santos Farias.pdf: 1234303 bytes, checksum: 420e49b91acb05fb1346e95075411509 (MD5) Previous issue date: 2017-03-06 / CAPES, FAPEMA,CNPQ / This paper describes the development of a simple and new sensor electrochemical determination of flutamide in voltamétrica formulations pharmaceutical and artificial urine specimens using a carbon electrode vitreous (ECV) modified with oxidized carbon nanotubes and graphene oxide (NCO-OG), which was named ECV/NCO-OG. Electronic microscopy techniques scanning (SEM) and Raman Spectroscopy were used for the characterization of carbon based materials. The electrochemical response of the analyte front of the ECV/NCO-OG was investigated by cyclic voltammetry techniques (VC) and square wave voltammetry (VOQ). The sensor exhibited a high activity eletrocatalítica for the reduction of flutamide in 0.05 V vs. Ag/AgCl. The parameters experimental influence the response of the electrode was investigated and the optimum conditions were found for the electrode modified with NCO-OG, in Britton-Robinson buffer solution-BR on concentration of 0.1 mol L-1 (pH 5). The proposed sensor presented a wide range of linear response of concentration for the flutamide of 0.1 to 1000 µmol L-1 (or µ g L-1 27.6 to 0.27 g L-1) for n = 15 (R2 = 0.997), limit of detection (LOD), limit of quantification (LOQ), and sensitivity of 0.03 µmol L-1, 0.1 µmol L-1, and 0.30 µmol µA -1 L, respectively. The ECV/NCO-OG was successfully applied to the determination of flutamide in pharmaceutical formulations used in the treatment of prostate cancer and artificial urine samples. The results obtained with the proposed sensor were compared with the method described in the literature and showed a level of 95% confidence, demonstrating that there is no statistical difference between the method of reference and the method proposed. The addition and recovery studies show that the proposed method presents a satisfactory accuracy with average value of 101% recovery ( 1)%. for the fortified samples. / Este trabalho descreve o desenvolvimento de um simples e novo sensor eletroquímico para determinação voltamétrica de flutamida em formulações farmacêuticas e amostras de urina artificial empregando um eletrodo de carbono vítreo (ECV) modificado com nanotubos de carbono oxidado e óxido de grafeno (NCO-OG), o qual foi denominado ECV/NCO-OG. As técnicas microscopia eletrônica de varredura (MEV) e a Espectroscopia Raman foram utilizadas para a caracterização dos materiais à base de carbono. A resposta eletroquímica do analito frente ao ECV/NCO-OG foi investigada através das técnicas de voltametria cíclica (VC) e voltametria de onda quadrada (VOQ). O sensor exibiu uma alta atividade eletrocatalítica para a redução da flutamida em 0,05 V vs Ag/AgCl. Os parâmetros experimentais que influenciam a resposta do eletrodo foram investigados e as condições ótimas foram encontradas para o eletrodo modificado com NCO-OG, em solução tampão Britton-Robinson-BR na concentração de 0,1 mol L-1 (pH 5). O sensor proposto apresentou uma ampla faixa de resposta linear de concentração para a flutamida de 0,1 a 1000 µmol L-1 (ou 27,6 µg L-1 a 0,27 g L-1) para n=15 (R2=0,997), com limite de detecção (LOD), limite de quantificação (LOQ), e sensibilidade de 0,03 µmol L-1, 0,1 µmol L-1, e 0,30 µA µmol-1 L, respectivamente. O ECV/NCO-OG foi aplicado com sucesso para a determinação de flutamida em formulações farmacêuticas utilizadas no tratamento de câncer de próstata e amostras de urina artificial. Os resultados obtidos com o sensor proposto foram comparados com o método descrito na literatura e observou-se um nível de confiança de 95%, demonstrando que não há diferença estatística entre o método de referência e o método proposto. Os estudos de adição e recuperação mostram que o método proposto apresenta uma exatidão satisfatória com valor médio de recuperação de 101% ( 1) %. para as amostras fortificadas.
14

Mise en évidence et analyse de nouvelles isoformes du proto-oncogène c-Cbl et rôle émergeant de ce gène dans la régulation de l'apoptose et de la prolifération cellulaire

Krisztian, Kaszas 20 April 2007 (has links) (PDF)
Le proto-oncogène c-Cbl code pour une protéine cytoplasmique abondamment exprimé dans les tissus hématopoïétiques et testiculaires. Elle possède un rôle de protéine multi-adaptatrice et/ou de régulateur négatif des RTKs. Nous rapportons ici que l'expression majoritaire de c-Cbl dans le testicule de rat et de souris est limité aux cellules germinales et son expression augmente en présence de testostérone et diminue après traitement in vivo par l'anti-androgène flutamide. L'apoptose dépendante des androgènes survenant à la fin de la méïose 1 est notablement moins importante dans le testicule de souris KO pour c-Cbl (c-CblKO). Inversement, le nombre de Fibroblastes Embryonnaires de souris c-CblKO entrant en apoptose sous l'effet du stress oxydatif est bien plus élevé que celui des cellules provenant d'animaux sauvages. Ces résultats indiquent le rôle sur la survenue du processus apoptotique de c-Cbl. Nous avons aussi cloné trois autres isoformes de p120c-Cbl à partir d'extraits de spermatocytes pachytènes, appelées p115c-Cbl, p90c-Cbl et p85c-Cbl, en considération de leur taille déduite. Ces isoformes présentent, par rapport à la p120c-Cbl, soit une délétion (d1 pour la p115c-Cbl; d2 pour la p90c-Cbl) soit les deux délétions combinées (d1 + d2, p85c-Cbl). L'expression de la p120c-Cbl et de la p115c-Cbl a été détectée dans le testicule, le poumon, la rate, le thymus et le cerveau alors que celle de la p90c-Cbl et p85c-Cbl semble être restreinte aux cellules germinales. La délétion d1 correspond à l'exon 10 (acides aminés 459-502) et la d2 s'étend des exons 11 à 15 (acides aminés 514-768), provenant d'épissages alternatifs. Les deux délétions contiennent des régions riches en prolines (PR) possédant pour chacun d'eux un site de liaison à la protéine adaptatrice Grb2. Seule la p85 c-Cbl ne peut pas se lier à Grb2, démontrant que chacun de ces sites de liaison sont suffisants pour que la liaison Grb2-c-Cbl puisse avoir lieu. D'autre part, les cellules transfectées par la p90 c-Cbl prolifèrent plus rapidement que celles transfectées avec les autres isoformes de c-Cbl. L'ensemble de ces résultats montrent que c-Cbl possède un rôle finement régulé dans la spermatogenèse, comme l'atteste l'hypofertilité des animaux c-Cbl KO, et que cette régulation pourrait en parti provenir d'une balance entre les différentes isoformes de c-Cbl.
15

Recombinant production and in silico analysis of the Androgen receptor ligand binding domain

Simila, Henry Allan January 2006 (has links)
The androgen receptor (AR) fulfils important roles for both sexes. By mediating the biological function of androgens, the AR has remained the target for endocrine therapies treating prostate cancer. The AR also determines the effectiveness of medroxyprogesterone acetate (MPA) in treating AR positive breast cancer. Every man will be affected by prostate cancer if he lives long enough. Prostate cancer continues to be a leading cause of death for males despite research into this cancer covering more than 60 years since Huggins' seminal 1941 study showing that androgens play a key role in this cancer. Unfortunately, significant advances have not been forthcoming and the effect of treatment has remained largely the same over past decades, whereby initial treatment provides temporary remission but eventually advanced cases become refractory to further intervention and the disease recurs in a more aggressive form. A plethora of factors are exquisitely sensitive to minute changes in the AR's structural profile, which can be altered by a single mutation, resulting in aberrant activity. A principal feature of these variant ARs associated with prostate cancer, is enhanced capacity to bind a number of molecules other than its cognate ligand, dihydrotestosterone (DHT). The promiscuous activity of this receptor leads to continued AR signalling and stimulus for the cancer despite low androgen levels induced by treatment regimes. A key question is whether mutations occurring within the AR occur as a result of cancer or contribute to the propagation of the cancer. Recent research has demonstrated that treatments incorporating anti-androgens such as flutamide, which are designed to impede prostate cancer progression by inhibiting AR activity, may actually provide selective pressure favouring somatic mutation of the receptor to take place. The specific changes to the AR which are responsible for gains of function have not been resolved as their crystal structures, which are used to provide conformational analysis of proteins, are tremendously problematic to produce with little success found in literature. Generating representative crystals of the AR protein involves producing soluble recombinant protein. Unfortunately the AR is prone to aggregation and is highly unstable, especially in the presence of antagonistic molecules or absence of a stabilising ligand, preventing the protein from being maintained in the soluble state required for crystallization. In order to produce sufficient quantities of soluble material for crystallization, the androgen receptor's ligand binding domain (LBD) was produced as a recombinant protein in Escherichia coli bacteria strain BL21 (DE3) in the presence of DHT, flutamide, as well as in the absence of ligand. Since soluble unbound AR-LBD has not been produced until now, the bacterial culture containing no ligand was further processed to the stage of cleaving the purification tag from the recombinant protein and represents considerable progress into producing soluble material for crystallizing the troublesome yet considerably important AR in the absence of ligand. Although distinct from prostate cancer in males, AR activity in breast tissue is also a factor determining the action of drugs, such as MPA, included in therapies aimed at breast cancer. The use of MPA has declined primarily due to its adverse effects including unsuccessful generation of a biological response, as well as the advent of other drugs administered for hormonal therapies treating breast cancer. Alternative drugs are needed when breast cancer therapies fail as tumours develop resistance to primary drugs. Although there are a number of drugs on the market, success would be maximised if the determined therapy is matched with the patient, based for example, on their genetic makeup. There is a conundrum whereby some patients with an AR do not respond to MPA, a drug normally recognised by the receptor. In clinical trials it was discovered that an AR with threonine instead of methionine at residue 780 (M780T) fails to activate in response to MPA, but the exact mechanism has remained elusive and needs to be answered at the molecular level. The X-ray crystallographic studies that generate 3D images of macromolecules and wet chemistry, which have traditionally been used to provide insight into science in these dimensions, are incorporated with computer based molecular simulation. This is both complementary and distinct to traditional scientific methodologies, enabling further elucidation of protein-protein interactions, and the influence applied to such inter-relations by natural and drug ligands. This approach has been used, and is continually developed, to understand the binding mechanisms of current drugs as well as designing new drugs. In order to produce a receptor representing the M780T variant, the crystal structure representing the AR-LBD was mutated in silico, into which MPA was then docked. It was found that MPA binds into the M780T AR-LBD with considerably more spatial displacement compared to the position of DHT in the crystal structure, and is predicted to be the primary reason for the inability of MPA to activate this variant AR. The clarification of MPA binding and failure to elicit a response from the variant AR is significant for a cohort of breast cancer patients, as not only does the presence of an AR in the tumour determine the effectiveness of MPA, but correct composition of the AR, specifically, the absence of a M780T mutation. In the absence of this AR mutation, MPA could effectively be used either as an alternative to primary drugs, or in secondary therapies when primary therapies fail. Aberrant activity of variant ARs in response to MPA should also be taken into consideration when analysing drug studies about the effectiveness of MPA. The findings on the loss of response to MPA by the M780T variant AR have been included in the journal article &quotDecreased Androgen Receptor Levels and Receptor Function in Breast Cancer Contribute to the Failure of Response to Medroxyprogesterone Acetate" appearing in the September 2005 issue of Cancer Research journal.

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