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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.
1

Estrogenic Compounds Protect Rat Cardiac Myoblasts (H9c2 Cells) Against Doxorubicin-Induced Cell Death

Abbas, Hesham Magdi 01 January 2006 (has links)
The antineoplastic drug doxorubicin is widely used in the treatment of various types of cancers including breast, colon and lung cancer. However, doxorubicin has adverse effects on the heart and prolonged doxorubicin administration results in cardiomyopathy and congestive heart failure. In the present study we have established that treatment of rat cardiac myoblasts (H9c2 cells) for 24 hours with doxorubicin resulted in concentration and time dependent cell death as determined by proliferation assay. Almost 50-55% cell death was attained at 24 hours treatment of H9c2 cells with 5 μM doxorubicin. We have selected about 50% cell injury as an optimum doxorubicin-induced cell injury because once this threshold is reached, cells became irreversibly injured and are unable to respond to protective treatment. We have observed that another potent antineoplastic drug, cyclophosphamide, had no cardiotoxic effects even with exposure at 35 μM concentrations for a treatment time of up to 72 hours. Pretreatment of H9c2 cells for 24 hours with 100 nM 17β-estradiol protects about 30% cell death against subsequent treatment for 24 hours with 5 μM doxorubicin. Interestingly 500 nM quecertin and 20 μM resveratrol pretreatment provide about 30% and 40% protection, respectively, to the H9c2 cells against subsequent doxorubicin treatment. However, diethylstilbestrol (DES), bisphenol A, and estrone exhibit no protective effects. It is concluded that 17β-estradiol, resveratrol and quercetin considerably protect H9c2 cells against doxorubicin-induced cell death.
2

EFEITO DO RESVERATROL NA CAPACIDADE FAGOCÍTICA E NA PRODUÇÃO DE ESPÉCIES REATIVAS DE OXIGÊNIO E NITROGÊNIO DE MACRÓFAGOS PERITONEAIS DE RATOS MACHOS E DE FÊMEAS (DIESTRO E PROESTRO)

Borille, Josimar Mariano 29 April 2011 (has links)
Made available in DSpace on 2017-07-21T19:59:55Z (GMT). No. of bitstreams: 1 Josimar Borille.pdf: 3226589 bytes, checksum: cb8561fb2eb7f3379035bac6be315d0d (MD5) Previous issue date: 2011-04-29 / Resveratrol is a phytoalexin found in several plants, like grapes (Vitis vinifera), synthesized in response to injury, attack by fungior, mechanical action and also by ultraviolet radiation Currently this bioactive compound has been the subject of interesting research, due to some properties that have already been assigned such as antioxidant and phytoestrogen. Its antioxidant activity is wellknown and is conferred by its ability to capture free radicals produced by cells or to interfere with signaling pathways of free radical production and detoxification. Furthermore, it is known that resveratrol exhibits characteristics of phytoestrogens, being molecularly similar to oestrogen. The intake of bioactive compounds in the diet is important because they exert effects on immune responses. Macrophages are cells in our immune system that are constituents of the mononuclear phagocytic system, which is our first line of defense against infectious agents. Several authors have reported that these cells express receptors for oestrogen hormones, and are regulated by these. So this study aimed to investigate the effect of resveratrol on the functionality of rat´s peritoneal macrophages, making a comparative study between males and females. Macrophages were obtained median laparotomy from the peritoneal cavity of Wistar rats divided into 3 groups (males, females in diestrus and proestrus females). Macrophages in culture medium RPMI 1640 supplemented with fetal calf serum (10%) were seeded in culture plates and incubated in an incubator with humid atmosphere of 5% CO2 for 2 hours. After complete adhesion, the cells were treated for a period of 24 hours with 5 and 10 M resveratrol, quercetin 5 and 10M (control of antioxidant activity) and 17-estradiol 0.01M and 10M (control of estrogenic activity). Afterwards the production of reactive oxygen and nitrogen were evaluated as well as the phagocytic capacity of macrophages treated. Resveratrol 10M significantly inhibited the: production of nitric oxide (NO) measured using the Griess reagent and production hydrogen peroxide (H2O2) determined by use of reagent xylenol orange. However the resveratrol didn’t change the phagocytic capacity under opsonized and nonopsonized particles assessed by optical microscopy. The inhibition of NO and H2O2 production by resveratrol was homogeneous among the groups. This inhibitory effect on NO production and H2O2 was also observed for quercetin.The treatment with 17-estradiol reduced production of NO and H2O2 induced by LPS only for macrophages in rats males. The immunosuppressive effects of resveratrol corroborate the described anti-inflammatory and antioxidant potential of this phenolic compound. Resveratrol in this study, compared to 17-estradiol and quercetin, shown to have antioxidant effects stronger than phytoestrogens. It was observed yet that its effect may vary between groups, and males and females in diestrus respond similarly to treatment with resveratrol and females in proestrus, the answer is different, thereby displaying a pre-modulation by 17-estradiol which these groups were exposed. However, in future, these results will need to be confirmed. / O resveratrol é uma fitoalexina encontrada em várias plantas, como por exemplo, na uva (Vitis vinifera),sintetizado em resposta a injúrias por ataques fúngicos ou mecânicos e ainda pela ação da radiação ultravioleta. Atualmente este composto tem sido alvo de interessantes pesquisas, devido às propriedades que já lhe foram atribuídas, tais como antioxidante, antiinflamatória, antitumoral e mais recentemente fitoestrogênica. Sua ação antioxidante já é bem conhecida e lhe é conferida por sua capacidade de captar radicais livres produzidos pelas células ou mesmo interferir em vias de sinalização que culminam na produção de radicais livres ou de sua detoxificação através de enzimas antioxidantes. Além disso, é sabido que o resveratrol apresenta atividade fitoestrogênica, por ser uma molécula similar ao hormônio estrogênio. A ingestão de compostos bioativos pela dieta é importante, pois estes exercem efeitos moduladores em geral, inclusive sobre as respostas imunes. Os macrófagos são células do sistema imune que fazem parte do sistema mononuclear fagocitário, que constitui a primeira linha de defesa frente a agentes infecciosos. Diversos autores já relataram que os macrófagos expressam receptores para estrogênio e, por conseguinte, são reguladas por este hormônio. Assim este estudo teve por objetivo investigar o efeito de resveratrol na funcionalidade de macrófagos peritoneais de ratos, fazendo um estudo comparativo entre machos e fêmeas. Os macrófagos foram obtidos por laparatomia mediana da cavidade peritoneal de ratos Wistar distribuídos em três grupos: 1) machos, 2) fêmeas em diestro e 3) fêmeas em proestro, sendo as fêmeas previamente identificadas quanto a fase do ciclo estral por análise de microscopia do material vaginal. Os macrófagos em meio de cultura RPMI 1640 suplementado com soro fetal bovino (10%) foram semeados em placas de cultivo e incubados em estufa de atmosfera úmida com 5% de CO2 por 2 horas. Após completa adesão, as células foram tratadas pelo período de 24 horas com resveratrol 5 e 10M, quercetina 5 e 10 M (controle de atividade antioxidante) e 17- estradiol 0,01 e 10M (controle de atividade estrênoigca). Na seqüência avaliou -se a produção de espécies reativas de oxigênio e nitrogênio, bem como a capacidade fagocítica dos macrófagos tratados. O resveratrol nas concentrações de 5 e 10M inibiu significativamente a produção de óxido nítrico (NO) avaliada utilizando-se o reagente de Griess e a produção peróxido de hidrogênio (H2O2) determinada pelo emprego do reagente xylenol orange. Todavia o resveratrol não alterou a capacidade fagocítica dos macrófagos às partículas de zimosan opsonizadas e não opsonizadas que foi avaliada por microscopia óptica. A inibição da produção de NO e H2O2 pelo resveratrol foi similar entre os grupos. Esse efeito inibitório na produção de NO e H2O2 foi também observado para a quercetina. Já os tratamentos com 17-estradiol reduziram a produção de NO e H2O2 induzida por LPS apenas dos macrófagos de ratos machos. Comparado com a quercetina e com o 17-estradiol, o resveratrol demonstrou ter efeito antioxidante mais acentuado do que fitoestrogênico. De fato, os efeitos imunossupressores do resveratrol, observados neste estudo, corroboram com o descrito potencial antioxidante e antiinflamatório deste composto. Todavia observou-se que o efeito do resveratrol pode ser diferente entre os grupos, sendo que machos e fêmeas em diestro respondem de maneira similares aos tratamentos com resveratrol, que por sua vez diferem da resposta das fêmeas em proestro, inferindo-se assim a existência de uma pré-modulação pelo 17-estradiol a qual esses grupos estavam expostos. Entretanto outros estudos se fazem necessários para comprovar esta observação.
3

Avaliação da atividade estrogênica das águas do Rio Paraíba do Sul / Evaluation of estrogenic activity in water samples from Paraiba do Sul River

Rocha, Guilherme Casoni da 14 December 2012 (has links)
A poluição da água doce no estado de São Paulo ocorre por diversas causas. Entre elas está a ineficiência do serviço de tratamento de esgoto sanitário. Alguns componentes do esgoto sanitário são desreguladores endócrinos, entre eles estão os hormônios naturais e sintéticos excretados pelos seres humanos. Estas substâncias causam modificações no sistema reprodutivo como, por exemplo, câncer, feminização, alterações na transcrição genética, alteração nas gônadas, indução à síntese de vitelogenina, entre outros. O objetivo desse trabalho foi testar a atividade endócrina das águas do rio Paraíba do Sul, em Pindamonhangaba, SP. Para tanto, amostras de água do rio foram utilizadas para a quantificação dos hormônios, 17-etinilestradiol, 17-estradiol e levonorgestrel por meio da técnica de cromatografia líquida de alta eficiência (HPLC). Além disso, foram realizados testes crônicos com peixes (Danio rerio) no interior do rio e em laboratório, e uma posterior quantificação de vitelogenina. Os resultados não indicaram concentrações detectáveis dos hormônios pelo método empregado. Entretanto, foi detectada a indução de vitelogenina nos machos de Danio rerio. Esse fato indica a atividade estrogênica da água utilizada. São necessários outros estudos para a avaliação de quais substâncias presentes na água, estão causando as alterações endócrinas nos peixes, entre eles a utilização de índices para priorizar o local inicial dessas pesquisas. Esses estudos são importantes para a conservação da biodiversidade aquática do rio Paraíba do Sul / Freshwater pollution in São Paulo state, Brazil, occurs due a several reasons. Among them there is the inefficiency of the sewage treatment service. Some sewage components are endocrine disrupters, including natural and synthetic hormones excreted by humans. These substances cause modification on reproductive system such as cancer, feminization, gene transcription and gonad alterations, vitellogenin synthesis induction, among others. The aim of this work was to evaluate the endocrine activity of the river Paraíba do Sul, at Pindamonhangaba city, Brazil. For this, river water samples were collected for the quantification of the hormones, 17- etinylestradiol, 17-estradiol and levonorgestrel by high performance liquid chromatography (HPLC). Furthermore, chronic assays were performed with fish (Danio rerio) into the river and in the laboratory, following quantification of biomarker vitellogenin. The studied hormones were not detected by employed methods. However, induction of vitellogenin in male of Danio rerio was detected indicating estrogenic activity of water. Further studies are necessary for the assessment of which substances into the water are causing the endocrine disruption in fish. These studies are important for the preservation of aquatic biodiversity of the Paraiba do Sul River
4

Avaliação da atividade estrogênica das águas do Rio Paraíba do Sul / Evaluation of estrogenic activity in water samples from Paraiba do Sul River

Guilherme Casoni da Rocha 14 December 2012 (has links)
A poluição da água doce no estado de São Paulo ocorre por diversas causas. Entre elas está a ineficiência do serviço de tratamento de esgoto sanitário. Alguns componentes do esgoto sanitário são desreguladores endócrinos, entre eles estão os hormônios naturais e sintéticos excretados pelos seres humanos. Estas substâncias causam modificações no sistema reprodutivo como, por exemplo, câncer, feminização, alterações na transcrição genética, alteração nas gônadas, indução à síntese de vitelogenina, entre outros. O objetivo desse trabalho foi testar a atividade endócrina das águas do rio Paraíba do Sul, em Pindamonhangaba, SP. Para tanto, amostras de água do rio foram utilizadas para a quantificação dos hormônios, 17-etinilestradiol, 17-estradiol e levonorgestrel por meio da técnica de cromatografia líquida de alta eficiência (HPLC). Além disso, foram realizados testes crônicos com peixes (Danio rerio) no interior do rio e em laboratório, e uma posterior quantificação de vitelogenina. Os resultados não indicaram concentrações detectáveis dos hormônios pelo método empregado. Entretanto, foi detectada a indução de vitelogenina nos machos de Danio rerio. Esse fato indica a atividade estrogênica da água utilizada. São necessários outros estudos para a avaliação de quais substâncias presentes na água, estão causando as alterações endócrinas nos peixes, entre eles a utilização de índices para priorizar o local inicial dessas pesquisas. Esses estudos são importantes para a conservação da biodiversidade aquática do rio Paraíba do Sul / Freshwater pollution in São Paulo state, Brazil, occurs due a several reasons. Among them there is the inefficiency of the sewage treatment service. Some sewage components are endocrine disrupters, including natural and synthetic hormones excreted by humans. These substances cause modification on reproductive system such as cancer, feminization, gene transcription and gonad alterations, vitellogenin synthesis induction, among others. The aim of this work was to evaluate the endocrine activity of the river Paraíba do Sul, at Pindamonhangaba city, Brazil. For this, river water samples were collected for the quantification of the hormones, 17- etinylestradiol, 17-estradiol and levonorgestrel by high performance liquid chromatography (HPLC). Furthermore, chronic assays were performed with fish (Danio rerio) into the river and in the laboratory, following quantification of biomarker vitellogenin. The studied hormones were not detected by employed methods. However, induction of vitellogenin in male of Danio rerio was detected indicating estrogenic activity of water. Further studies are necessary for the assessment of which substances into the water are causing the endocrine disruption in fish. These studies are important for the preservation of aquatic biodiversity of the Paraiba do Sul River
5

EFEITO DA GENISTEÍNA NA FUNCIONALIDADE DE MACRÓFAGOS: UM ESTUDO COMPARATIVO ENTRE RATOS MACHOS E FÊMEAS

Juraszeck, Camila 19 April 2011 (has links)
Made available in DSpace on 2017-07-21T19:59:54Z (GMT). No. of bitstreams: 1 Camila Juraszeck.pdf: 2382188 bytes, checksum: de4167e36249ed23da96ba41c11fe677 (MD5) Previous issue date: 2011-04-19 / Genistein has estrogenic activity and can bind to estrogen receptors (ER), so it is considered a phytoestrogen. ER have been reported in macrophages and in that sense, the estrogens modulate immune responses. Despite the sexual dimorphism of the immune responses in females and males is well established, there are few studies that elucidate the role of bioactive compounds such as genistein among the genders. We investigated the effects of genistein on mice macrophage functionality, benchmarking males and females, which are divided into three groups according to sex and stage of the estrous cycle. First we checked the cytotoxicity,employing the technique of MTT reduction, in the following compounds: genistein, quercetin and 17-estradiol in the presence or absence of lipopolysaccharide (LPS). And none of these altered cell viability. To test the functionality of macrophages, the cells were treated for 24 h with two concentrations of genistein and quercetin (5M and 10M) as well as two concentrations of 17-estradiol (0,01 and 10 M), besides the control of the vehicle, the dimethylsulfoxide (DMSO) at 0,5%. The macrophages’ funtion standarts determined by spectrophotometry were the NO production in both basal and LPS induced, the production of H2O2 induced by LPS and by light microscopy was evaluated the phagocytic ability of macrophages, which were challenged to phagocytize Zymosan particles opsonized or not, after two hours of treatments. The results show a inhibition percentage of basal NO production in macrophages treated with genistein 10M, 34% and 40% for males and females in diestrus, respectively. In the macrophages obtained from females in proestrus quercetin treatment alone (in lower and higher concentration) showed a decrease in basal NO production significantly compared to control, with inhibition of 24% and 34% respectively. As NO production induced by LPS, macrophages from males showed significant inhibition of production with all treatments (except quercetin 5 μM), while in females in diestrus, treatments genistein (5 and 10 μM) and quercetin (5 and 10 μM ), this parameter significantly decreased functional macrophages, with values corresponding respectively to 25%, 30%, 17% and 31%. Once in females in proestrus, basal NO production induced by LPS and was inhibited only by quercetin (10M). All treatments of macrophages collected from the male reduced the production of H2O2 and genistein inhibition percentage of 10M of 27%. In females in diestrus was observed that treatment with genistein 5 e 10 M and quercetin 10M inhibited respectively 29%, 32% and 37% the production of H2O2. The H2O2 production by macrophages from females in proestrus was significantly inhibited by all treatments (except estradiol 0,01 ηM and quercetin 10M), and the percentage inhibition of genistein 5 e 10M was 22%. The phagocytic activity of macrophages was not affected by treatment with genistein for either group. Our results suggest that NO production, macrophages premodulated by exposure to 17-estradiol, the effect of genistein is less pronounced, may possible be explained by downregulation of ER in ex vivo treatments. In conclusion we can infer that, the use of genistein should account for sex, and therefore variations in serum hormone concentrations of 17-estradiol (sexual cycle) in females. / A genisteína têm atividades estrogênicas, e pode se ligar aos receptores de estrogênio (RE), por isso é considerada um fitoestrógeno. RE têm sido relatados em macrófagos e nesse sentido, os estrogênios modulam as respostas imunes. Apesar do dimorfismo sexual das respostas imunes de fêmeas e machos estar bem estabelecido, existem poucos estudos que elucidem o papel de compostos bioativos como a genisteína entre os sexos. Neste estudo, investigamos os efeitos da genisteína na funcionalidade de macrófagos de ratos, avaliando comparativamente machos e fêmeas, sendo estes divididos em três grupos de acordo com o sexo e a fase do ciclo estral. Primeiramente verificamos a citotoxicidade, empregando a técnica de redução do MTT, dos seguintes compostos: genisteína, quercetina e 17-estradiol, na presença ou ausência de lipopolissacarídeo (LPS). E nenhum destes alterou a viabilidade celular. Para o ensaio da funcionalidade dos macrófagos, as células foram tratadas por 24 horas com duas concentrações de genisteína e quercetina (5M e 10M), como também duas concentrações de 17-estradiol (0,01 e 10 M), além do controle do veículo, o dimetilsulfoxido (DMSO) na concentração de 0,5%. Dos parâmetros de funcionalidade dos macrófagos, foram determinadas por espectrofotometria a produção de NO tanto basal quanto a induzida por LPS, bem como a produção de H2O2 induzida por LPS, e por microscopia de luz realizou-se a avaliação da capacidade fagocítica dos macrófagos, que foram desafiados a fagocitar partículas de Zimosan opsonizadas ou não, após tratamentos de 2 horas. Os resultados encontrados revelam uma porcentagem de inibição da produção de NO basal de macrófagos tratados com genisteína 10 M de 34% e 40%, para machos e fêmeas em diestro, respectivamente. Nos macrófagos obtidos das fêmeas em proestro apenas o tratamento quercetina (em menor e maior concentração) apresentou diminuição na produção de NO basal significativa em relação ao controle, com inibição de 24% e 34% respectivamente. Quanto a produção de NO induzida por LPS, macrófagos de machos apresentaram inibição significativa da produção com todos os tratamentos (exceto quercetina 5M), enquanto nas fêmeas em diestro, os tratamentos genisteína (5 e 10 M) e quercetina (5 e 10 M), diminuíram significativamente esse parâmetro funcional de macrófagos, com os valores correspondentes respectivamente a 25%, 30%, 17% e 31%. Já nas fêmeas em proestro, a produção de NO basal e induzida por LPS foi apenas inibida pela quercetina (10M). Todos os tratamentos dos macrófagos obtidos de machos reduziram a produção de H2O2, sendo porcentagem de inibição da genisteína 10 μM de 27%. Nas fêmeas em diestro observa-se que os tratamentos com genisteína 5 e 10M e quercetina 10 M inibiram respectivamente em 29%, 32% e 37% a produção de H2O2. A produção de H2O2 pelos macrófagos das fêmeas em proestro foi inibida significativamente por todos os tratamentos (exceto estradiol 0,01 M e quercetina 10 M), sendo que a porcentagem de inibição da genisteína 5 e 10 M foi de 22%. A atividade fagocítica dos macrófagos não foi influenciada pelo tratamento com a genisteína para nenhum dos grupos. Nossos resultados são sugestivos de que a produção de NO nos macrófagos prémodulados pela exposição ao hormônio estradiol o efeito da genisteína é menos acentuado, podendo ser explicado por possível downregulation dos RE em tratamentos ex vivo. Em conclusão podemos inferir que para o emprego da genisteína deve se levar em consideração o sexo, e por conseguinte, a variação da concentração hormonal sérica de 17-estradiol (ciclo sexual) em fêmeas.
6

Heterogeneous photocatalytic degradation of organic pollutants in water over nanoscale powdered titanium dioxide : the photocatalytic degradation of organic compounds in water (Reactive Orange 16, Triclocarbon, Clopyralid and Estrogens (estrone, 17ß-estradiol, and 17α-ethinylestradiol)) was studied : the reaction kinetics and the effect of the operating parameters on the performance of the system were determined; a comparison with other advanced oxidation processes (O₃, H₂O₂, UV) was also made

Mezughi, Khaled M. January 2010 (has links)
Organic contaminants from industrial and/or domestic effluents may be harmful to humans directly or indirectly by degrading the quality of the aquatic environment. Consequently these contaminants must be reduced to levels that are not harmful to humans and the environment before disposal. Chemical, physical and biological methods exist for the removal of these pollutants from effluents. Among the available chemical methods, heterogeneous photocatalytic oxidation has been found particularly effective in removing a large number of persistent organics in water. In this study, photocatalytic degradation was explored for the removal of reactive azo-dye (textile dye), triclocarban (disinfectant), clopyralid (herbicide) and three endocrine disrupting compounds (EDCs) (estrone, 17ß-estradiol and 17α-ethinylestradiol) from synthetic effluents. The major factors affecting the photocatalytic processes including the initial concentration of the target compounds, the amount of catalyst, the light intensity, the type of catalyst, the electron acceptor, the irradiation time and the pH were studied. Other oxidation techniques including (O3, H2O2, UV) were also studied. Generally UV light is used in combination with titanium dioxide, as photocatalyst, to generate photoinduced charge separation leading to the creation of electron-hole pairs. The holes act as electron acceptors hence the oxidation of organics occur at these sites. These holes can also lead to the formation of hydroxyl radicals which are also effective oxidants capable of degrading the organics. The results obtained in this study indicated that photolysis (i.e. UV only) was found to have no effect on the degradation of reactive azo-dye (RO16). However, complete photocatalytic degradation of 20 mg/L (3.24×10-2 mM) RO16 was achieved in 20 minutes in the presence of 1g/L TiO2 Degussa P25 at pH 5.5. Comparison between various types of catalysts (i.e. Degussa P25, VP Aeroperl, Hombifine N) gave varied results but Degussa P25 was the most effective photocatalyst hence it was selected for this study. For RO16 the optimum catalyst concentration was 0.5 g/L TiO2 with initial concentration of 20 mg/L RO16. It was found that the disappearance of RO16 satisfactorily followed the pseudo first-order kinetics according to Langmuir-Hinshelwood (L-H) model. The rate constant was k= 0.0928 mol/min. Photodegradation of TCC was studied in 70%v acetonitrile: 30%v water solutions. UV light degraded TCC effectively and the reaction rates increased with decreasing initial concentration of TCC. UV/TiO2 gave unsatisfactory degradation of triclocarban (TCC) since only 36% were removed in 60 minutes with initial concentration of TCC 20 mg/L. The degradation of clopyralid and the EDCs was studied using three oxidation systems UV/TiO2, UV/H2O2 and O3. Complete degradation of clopyralid (3,6-DCP) was achieved with UV/TiO2 in about 90 minutes at an optimum catalyst concentration of 1g/L. Zero-order kinetics was found to describe the first stage of the photocatalytic reaction in the concentration range 0.078-0.521 mM. At pH 5 the rate constant was 2.09×10⁻⁶ ± 4.32×10⁻⁷ M.s⁻¹. Complete degradation of all the three EDCs was achieved with UV/H₂O₂ in 60 minutes at catalyst concentration of (2.94×10⁻² M). On the other hand complete degradation of the EDCs was achieved in just 2 minutes with ozonation. For high concentration EDCs, TiO₂/UV gave low efficiency of degradation as compared with ozone and H2O2/UV. First-order kinetics was found to describe the photocatalytic reaction of the EDCs.
7

Development of electrochemical ZnSe Quantam dots biosensors for low-level detection of 17β-Estradiol estrogenic endocrine disrupting compound

Jijana, Abongile Nwabisa January 2010 (has links)
Magister Scientiae - MSc / The main thesis hub was on development of two electrochemical biosensors for the determination of 17β-estradiol-estradiol: an estrogenic endocrine disrupting compound. Endocronology have significantly shown that the endocrine disruptors contribute tremendously to health problems encountered by living species today, problems such as breast cancer, reproductive abnormalities, a decline in male population most significant to aquatic vertebrates, reduced fertility and other infinite abnormalities recurring in the reproductive system of mostly male species. The first biosensor developed for the detection of 17β-estradiol-estradiol endocrine disrupting compound; consisted of an electro-active polymeric 3-mercaptoprorionic acid capped zinc selenide quantum dots cross linked to horseradish peroxidase (HRP) enzyme as a bio-recognition element. The second biosensor developed was comprised of cysteamine self assembled to gold electrode, with 3-mercaptopropionic acid capped zinc selenide quantum dots cross linked to cytochrome P450-3A4 (CYP3A4) enzyme in the presence of 1-ethyl-3-(3- dimethylaminopropyl)carbodiimide hydrochloride and succinimide. / South Africa

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