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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.
481

Evaluación de la aplicación de estiércol animal en relación a la presencia, disponibilidad y biodisponibilidad de estrona (E1), 17β-estradiol (E2) y 17α-etinilestradiol (EE2) en suelos degradados

Uribe Laplechade, Catalina del Carmen January 2018 (has links)
Tesis presentada a la Universidad de Chile para optar al grado de Magíster en Química área de Especialización en Química Ambiental y Memoria para optar al Título de Químico / Con el objeto de buscar alternativas de producción más amigables con el medio ambiente, y evitar el deterioro de los ecosistemas, la producción silvoagropecuaria ha generado opciones sustentables y ecológicas como la agricultura orgánica, la cual conserva o aumenta la materia orgánica del suelo reciclando los residuos de cosecha, poda, estiércol y guano de animales, a través de distintos sistemas de incorporación al suelo. Según la Ley 20.089, el estiércol corresponde a fecas, orinas y productos de cama de animales, que no han sido compostado. El guano y la orina de los animales contienen cantidades importantes de nitrógeno, fósforo, potasio y otros elementos necesarios para el crecimiento de las plantas. La combinación de estiércol, paja de cereales y restos hortícolas es una mezcla de alta calidad como abono para el suelo. La composición de los guanos es muy variable y generalmente depende de la dieta que se le suministra al animal. La legislación chilena señala que la carga ganadera establecida se debe fijar considerando que no se debe sobrepasar el límite de 170 kg de nitrógeno·ha-1·año-1. Por otro lado, la ganadería intensiva crea problemas de depósito de estiércol y contaminación de agua. En este tipo de ganadería de producción intensiva el uso de fármacos u otros insumos es una práctica habitual que tiene como objetivos, aumentar la eficiencia en la engorda de los animales y la producción de leche. Uno de los problemas que puede provocar este hecho, es el aumento de la concentración de algunos contaminantes emergentes como lo son las hormonas estrogénicas naturales y sintéticas, por ejemplo, la estrona (E1), el 17β-estradiol (E2) y el 17α-etinilestradiol (EE2), que están consideradas disruptores endocrinos, y aunque se encuentren en muy bajas concentraciones, pueden provocar serios daños en animales y en seres humanos. Por esto, el objetivo de este trabajo fue evaluar la biodisponibilidad de dos hormonas naturales (E1 y E2) y una hormona sintética (EE2) en suelos restaurados con estiércol, empleando plantas de trigo como indicadores y compararlas con una extracción mediante hidroxipropil-β-ciclodextrina (HPCD). Para esto se evaluó la concentración de los tres analitos (E1, E2 y EE2) en estiércol de vacuno, cerdo y caballo, realizando una extracción asistida con ultrasonido, seguido de una etapa de clean up, derivatización y cuantificación en un cromatógrafo de gases acoplado a espectrometría de masas. También se realizó una caracterización física y química de los tres tipos de suelos y los distintos estiércoles, se determinó la fracción biodisponible en plantas de trigo cultivadas en suelos enmendados con estiércol y se estimó la concentración biodisponible mediante la extracción de las hormonas con ciclodextrina, para así validar este método como biosimulador a través de la comparación con los resultados obtenidos en el bioensayo con plantas de trigo. Finalmente, se realizó un estudio de degradación de las tres hormonas estrogénicas, aplicadas directamente a los suelos o agregadas a través del estiércol enriquecido con éstas, en dos periodos de tiempo, el primero durante treinta días y el segundo en siete días. Las hormonas naturales E1 y E2 se encontraron en los tres estiércoles, mientras que solo en el estiércol de cerdo se encontró la hormona sintética EE2. Los tres analitos se encontraron biodisponibles en las raíces de las plantas de trigo, siendo la EE2 en el suelo Codigua la que presentó mayor biodisponibilidad, el bioensayo con ciclodextrina correlacionó con la fracción biodisponible en las plantas de trigo, por lo tanto, el método biosimulador serviría como sistema predictivo en los tres suelos utilizados. Finalmente, el tiempo de degradación de las hormonas fue en general rápido, las tres hormonas se degradaron en su mayoría dentro de los dos primeros días, siendo la EE2 la más estable y la E2 la menos estable, ya que posiblemente ocurriría su degradación por oxidación a E1, por lo tanto, la concentración de E1 en las primeras horas tendería a aumentar / Intending to find environmentally production alternatives and avoid ecosystem damage, is that agro forestry production has generated sustainable and ecological alternatives as organic agriculture, which preserves or increases organic material from the ground by recycling harvest, pruning, manure and animal guano remains, all these through different ground incorporation systems. According to law no. 20.089, manure is composed by non composted feces, urine and animal bed products. Guano and urine from animals contains a significant amount of nitrogen, phosphor, potassium and some other elements needed for plants growth. The mixture made of manure, cereal straw and horticultural remains is a high quality fertilizer for the soil. Different guano compositions is very variable y generally depends on the animal diet. Current legislation points that established livestock load must be determinated considering not exceeding 170 kilograms limit of nitrogen·ha-1·year-1. On the other hand, intensive animal breeding creates manure deposit and water pollution problems. In this type of intensive animal breeding production, it is usual practice the use of drugs and other supplies that look for increase efficiency on animal fattening and milk production. One of the problems that this fact could cause is the increase on some emerging pollutants concentration as natural and synthetic estrogen hormones, like estrone (E1), 17β-estradiol (E2) y 17β-ethinylestradiol (EE2), which are considered as endocrine disruptors, that although are found on low concentration, can cause serious damage both in animals and in humans. Therefore, the main objective of this work was to evaluate the effect of the application of manure on soils and determine the bioavailable fraction of two natural hormones (E1 and E2) and a synthetic hormone (EE2) in wheat plants grown in the soils restored with manure, comparing the results with a bioassay using hydroxypropyl-β-cyclodextrin (HPCD) as an extractant. For this, the concentration of the three analytes (E1, E2 and EE2) in cow, pig and horse manure was evaluated, performing an assisted extraction with ultrasound, then a clean up, derivatization and measuring were made by in a coupled gas chromatograph to mass spectroscopy. A physical and chemical characterization of the three types of soils and the different manure was also carried out, the bioavailable fraction in wheat plants cultivated in soils amended with manure was determined and the bioavailable concentration was estimated by extracting the hormones with cyclodextrin, to validate this method as a biosimulator through the comparison with the results obtained in the bioassay with wheat plants. Finally, a study of degradation of the three estrogenic hormones, applied directly in the soil or added through the manure enriched with these, in two periods of time, the first during a month and the second for seven days. The natural hormones E1 and E2 were found in the three manures, and only synthetic mannitol EE2 was found in pig manure. The three analytes were found bioavailable in the roots of wheat plants with EE2 in Codigua soil having the highest bioavailability, the bioassay with cyclodextrin correlated with the bioavailable fraction in wheat plants, validating the biosimulator method as a predictive method, and finally, the time of degradation of hormones is generally fast, the three hormones are degraded mostly within the first two days, EE2 being the most stable and E2 the least stable, may because of this is degraded by oxidation to E1, therefore the concentration of E1 in the first hours tends to increase / Fondecyt
482

Exposição da próstata de fêmeas de gerbilo da Mongólia (Meriones unguiculatus) a doses ambientais de Bisfenol A e 17beta estradiol /

Bedolo, Carolina Marques January 2020 (has links)
Orientador: Sebastião Roberto Taboga / Resumo: A próstata é uma glândula componente do sistema genital dos mamíferos e sua principal função prostática é secretar um fluido levemente alcalino (pH 7,29) que contribui para a formação do líquido seminal. As fêmeas em certas espécies, como o roedor gerbilo da Mongólia (Meriones unguiculatus), apresentam próstata cuja morfologia se assemelha à porção ventral do complexo prostático masculino e à próstata feminina em humanos. Nas últimas décadas tem sido relatado um constante aumento da exposição a substâncias capazes de interferir na ação hormonal, conhecidas como disruptores endócrinos. O bisfenol A (BPA) pertence a uma das categorias de disruptores endócrinos presentes no meio ambiente. Estudos demonstram que a exposição a esse composto interfere negativamente na morfofisiologia prostática, favorecendo o estabelecimento de lesões pré-malignas e malignas. Além do BPA, uma das constantes problemáticas dos dias atuais é a exposição ambiental a hormônios exógenos como o estradiol (E2). Desta forma, a administração de fármacos com estrutura semelhante a hormônios esteroides pode exercer efeitos sobre a glândula, uma vez que os mesmos se ligam a seus receptores hormonais afetando a homeostasia prostática. O presente estudo teve como objetivo verificar as alterações morfofuncionais na próstata de fêmeas de gerbilo da Mongólia após tratamento perinatal com dose diária ambiental, ou seja, dose ambiental segura de BPA (50 µg/kg) e doses de 17-β estradiol (35 µg/kg), 3 vezes por semana p... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre
483

Hypertension artérielle, dysfonction endothéliale et stress oxydant dans un modèle animal d’apnée du sommeil : rôle protecteur de l’estradiol / Arterial hypertension, endothelial dysfunction and oxidative stress in an animal model of sleep apnea : protective role of estradiol

Ribon-Demars, Alexandra 23 September 2019 (has links)
L’hypertension artérielle est un problème de santé publique majeur, au centre de nombreuses pathologies. En étudiant la prévalence de l’hypertension, nous nous sommes intéressés à deux points en particulier que nous abordons dans ce manuscrit de thèse. Le premier est l’existence d’une relation bidirectionnelle entre l’hypertension et le syndrome de l’apnée du sommeil (SAS), maladie encore sous-diagnostiquée de nos jours. Le second concerne le fait que les hommes sont plus touchés par ces deux pathologies que les femmes, mais que cette tendance s’inverse au moment de la ménopause, suggérant un rôle protecteur des hormones ovariennes. Les mécanismes sous-jacents de la mise en place de l’hypertension ont été étudiés dans différentes maladies associées (athérosclérose, obésité, diabète), mais ils restent encore méconnus dans le SAS chez la femme ménopausée. Le travail de cette thèse vise à comprendre les mécanismes à l’origine de l’hypertension artérielle chez les femmes ménopausées atteintes du SAS. Pour cela, nous avons utilisé un modèle animal d’hypoxie intermittente (HI; 21%-10% O2 ; 10cycles/h ; 8h/jour). Ce modèle simule le profil physiopathologique observé chez les patients apnéiques, en particulier avec le développement de l’hypertension artérielle. La particularité de nos travaux de recherche est l’utilisation de rats femelles ovariectomisées (OVX), permettant ainsi de mimer la ménopause, contrairement à de nombreux modèles d’HI qui utilisent le rat mâle. Par ailleurs, nous avons également regardé le rôle de l’estradiol (E2) dans le développement de l’hypertension et sur les mécanismes sous-jacents induits par l’HI. Nos principales conclusions sont que l’HI engendre une élévation de la pression artérielle et de la concentration en endothéline-1 (un vasoconstricteur), mais que ceci est réversible avec le traitement à l'E2. Au niveau de l'aorte, l'OVX engendre une augmentation du stress oxydatif, mais, de nouveau, la supplémentation en E2 renverse cet effet. Les mécanismes de réponse à l'E2 sont différents selon le protocole suivi par l’animal ; après l’HI, l’E2 réduit l'activité des enzymes pro-oxydantes alors qu’en condition de normoxie (21% O2), l’E2 augmente l'activité des enzymes anti-oxydantes. Au niveau des poumons, l’HI augmente le stress oxydatif mais l’OVX a un effet chez les animaux en normoxie uniquement. Les effets de l'E2 sur le stress oxydatif sont tissu-dépendants. Le traitement à l'E2 permet de pallier les dysfonctions vasculaires / Arterial hypertension is a major public health problem, which is at the heart of many diseases. In studying the prevalence of hypertension, we focused in two specific points that we address in this thesis manuscript. The first one is the existence of bidirectional relationship between hypertension and sleep apnea syndrome (SAS), a disease that is still underdiagnosed today. The second is that men are more affected by these two conditions than women, but this trend reverses at the time of menopause, suggesting a protective role of ovarian hormones. The underlying mechanisms of the establishment of hypertension have been studied in various associated diseases (atherosclerosis, obesity, diabetes), but they are still unknown in SAS in menopausal women. This work aims to understand the mechanisms underlying high blood pressure in postmenopausal women with SAS. For this, we used an animal model of intermittent hypoxia (IH, 21% -10% O2, 10cycles/h, 8h/day). This model presents the same pathophysiological profile observed in apneic patients, in particular with the development of arterial hypertension. The unusual feature of our study is the use of ovariectomized (OVX) female rats, thus allowing to mimic the menopause, contrary to many models of IH which use the male rats. In addition, we also looked at the role of estradiol (E2) in the development of hypertension and on the underlying mechanisms induced by IH. Our main conclusions are that although IH causes elevation of blood pressure and endothelin-1 concentration (a vasoconstrictor), it is reversible with E2 treatment. In aorta, OVX generates an increase of oxidative stress, but, again, the supplementation in E2 reverses this effect. The mechanisms of response to E2 are different according to the protocol followed by the animal; after IH, E2 reduces the activity of pro-oxidant enzymes whereas in normoxia condition (21% O2), E2 increases the activity of antioxidant enzymes. In the lungs, IH increases oxidative stress, but OVX has an effect only in female rats exposed to normoxia. The effects of E2 on oxidative stress are tissue-dependent. E2 treatment overcomes IH-induced vascular dysfunction and may be clinically relevant in the treatment of SAS in postmenopausal women
484

Studium alternativních sestřihových forem estrogenního receptoru alfa v buněčných liniích karcinomu prsu / Study of alternatively spliced variants of estrogen receptor alpha in breast cancer cell lines

Lhota, Filip January 2010 (has links)
Filip Lhota: Study of alternatively spliced variants of estrogen receptor alpha in breast cancer cell lines Abstract: Estrogen receptor α (ER-α) is a transcription factor responsible for mediation of the activities of its natural ligand 17-β-estradiol (E2), the hormone that together with progesterone belongs to the key regulators of mammary epithelial as well as breast cancer cells proliferation. Except to the major gene product consisting of all eight coding exons of ER-α, numerous qualitatively and quantitatively different spliced variants originated from primary transcript by activity of alternative splicing is expressed. Despite that some of these spliced variants have been functionally characterized, their precise role on final ER-α cellular activity remains to be elucidated. The functional characterization of individual alternative forms of ER-α and description of its participation on the overall ER-α activity is important for our understanding of their biogenesis and is also critical for the delineation of molecular bases for ER-α regulation during anti cancer chemotherapy. This work aimed to study the influence of alternatively spliced ER-α variants on the growth characteristics of clones constructed from stable mammary tissue cell lines in regulation to cultivation conditions and cellular...
485

Insuficiência de vitamina D em pacientes infectados pelo HIV tratados com terapia antirretroviral contendo tenofovir /

Maria, Jéssika Carvalho. January 2015 (has links)
Orientador: Anderson Marliere Navarro / Banca: Rodrigo Carvalho Santana / Banca: Thais Borges César / Resumo: Introdução: A vitamina D é um nutriente essencial para a mineralização do esqueleto e manutenção de massa óssea. Evidências recentes têm demonstrado uma alta prevalência de deficiência de vitamina D em infectados pelo HIV, principalmente em uso de tenofovir (TDF), por afetar as células tubulares renais, causando a perda de eletrólito e a redução da massa óssea. Objetivo: avaliar os efeitos do tenofovir nos níveis séricos de vitamina D e seu impacto sobre a densidade mineral óssea em pacientes sob regime de tenofovir ou não. Metodologia: Estudo transversal com 127 indivíduos, de ambos os sexos, com idades entre 18 e 60 anos. Os participantes foram subdivididos em 3 grupos, sendo: grupo em uso do tenofovir (GTDF+): n= 48 participantes, grupo sem uso de tenofovir (GTDF-): n= 49 participantes e grupo controle (GC): n= 30 participantes soronegativos para HIV. Realizou-se dual energy x-ray absorptiometry (DXA) para avaliação da densidade mineral óssea (DMO) e composição corporal. Amostras de sangue periférico foram coletadas para determinações da 25 hidroxivitamina D (25(OH)D), hormônio da paratireoide (PTH), hormônio luteinizante (LH), hormônio folículo estimulante (FSH), testosterona, estradiol, creatinina, uréia, albumina, cálcio, magnésio e fósforo. Calculou-se a taxa de filtração glomerular e avaliação do consumo alimentar. Resultados: A vitamina D sérica apresentou valores insuficientes na maioria dos participantes e o consumo alimentar de vitamina D, cálcio e magnésio mostraram abaixo da recomendação dietética em todos os grupos do estudo. O GTDF+ apresentou valores séricos menores de vitamina D quando observado com os valores do grupo GTDF-. A deficiência de vitamina D foi observada em 31% dos pacientes em uso de TDF e em 20% dos pacientes sem uso de tenofovir. Observou-se que até 25% dos participantes em uso de tenofovir... / Abstract: Introduction: Vitamin D is an essential nutrient for the mineralization of the skeleton and maintenance of bone mass. Recent evidence has shown a high prevalence of vitamin D deficiency in HIV-infected, mainly in use of tenofovir (TDF), to affect the renal tubular cells, causing the loss of electrolyte and reduced bone mass. Objective: To evaluate the effects of tenofovir in serum levels of vitamin D and its impact on bone mineral density by comparing patients on tenofovir system versus non tenofovir. Methods: Cross-sectional study with 127 individuals of both genders, aged between 18 and 60 years. Participants were divided into the following 3 groups: group using tenofovir (GTDF+): n = 48 participants, group not using tenofovir (GTDF-): n = 49 participants and control group (CG): n = 30 participants seronegative for HIV. Dual energy x-ray absorptiometry (DXA) was performed to evaluate bone mineral density (BMD) and body composition. Peripheral blood samples were collected for the determination of 25-hydroxyvitamin D (25(OH)D), parathyroid hormone (PTH), luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone, estradiol, creatinine, urea, albumin, calcium, magnesium and phosphorus. The glomerular filtration rate was calculated and the dietary intake evaluated. Results: Vitamin D had insufficient serum levels in all study groups as shown inadequate dietary intake. The GTDF + group showed lower serum levels of vitamin D when viewed with the values of GTDF- group, and 31% of patients using TDF showed serum deficiency. It was observed that up to 25% of the participants use of tenofovir showed osteopenia, especially in the lumbar spine bone site, whereas the group without tenofovir was higher percentage for osteoporosis. Conclusion: Most of the participants infected with HIV under control or not of tenofovir had insufficient vitamin D deficient levels ... / Mestre
486

Kondom eller P-piller? : En livscykelanalys med fokus på miljöpåverkan / Condoms or birth control pills? : A life cycle analysis focused on the environmental impacts

Legind, Ann-Sofie January 2020 (has links)
Det finns ett ökat intresse för klimatet och miljöpåverkan hos gemene man och hos många en vilja att leva med en mer miljövänlig livsstil. När det kommer till preventivmedel och att välja det alternativ som passar en bäst, dessutom med hänsyn till vad som är det bästa för miljön, så är det en djungel där ute. Även preventivmedelsrådgivare upplever en bristande kunskap för att kunna ge bra råd inom ämnet. Det här arbetet skrevs för att jämföra miljöpåverkan mellan användandet av p-piller och kondom. Detta gjordes med hjälp av en kvalitativ litteraturstudie som i senare steg kompletterades med en kvantitativ fallstudie med fokus på livscykelanalys av båda produkterna. Livscykelanalyserna gjordes i två steg, först togs ett processträd fram med hjälp av litteraturstudien och dessa gjorde sedan grunden för livscykelanalysen som genomfördes med mjukvaran ReCiPe i SimaPro. Resultatet av studien blev att kondomen visar på större miljöpåverkan i förhållande till användandet av p-piller. Dock saknas det i ReCiPe den påverkan som hormonet i p-piller på både land- och marin miljö ger, vilket lett till att resultatet inte är helt tillförlitligt och det riskerar vara en betydande felkälla. / There is a growing interest for the climate and the environmental effect the average person has on its surroundings and many people choose to live more environmentally friendly. It’s a jungle out there when it comes to birth control and choosing the option that suits one best but also is the most environmentally sustainable option. Midwifes have expressed that they experience a lack of knowledge amongst themselves as to what contraceptive is the most environmentally friendly. This thesis compared the environmental effects between using the contraceptive pill or condom as birth control. This was done with the help of a qualitative literature study which later on was complemented with a quantitative case study focusing on lifecycle analysis of both the products. The lifecycle analysis was executed in two stages, whereas the first stage was developing a process tree with the help of the literature study. This was later used as the foundation for the second stage, which was the lifecycle analysis done with the help of the ReCiPe data in SimaPro. The results showed that the condom had a higher impact on the environment relative to the contraceptive pill. Although, from the ReCiPe data there were no indications that the hormones that are released from the contraceptive pill would have any effect on the land or marine environment. This lack of data poses a risk of a major fault in the results as the hormonal effects on the environment is the main issue with the pill.
487

Correlation Between Polychlorinated Biphenyls and Reproductive Hormone Levels of Men and Women

Cramblit, Caroline Hannah 27 April 2022 (has links)
No description available.
488

The Effect of Indomethacin Administration on the Splenic Changes Induced by Estradiol Supplementation in Ovariectomized New Zealand White Rabbits

Thurmond, Thane S., Ferslew, Kenneth E., Mccracken, Malcolm D., Coogan, Philip S. 01 January 1996 (has links)
In an effort to elucidate the mechanism by which indomethacin (IN) lessens the stimulatory effect of estradiol (E2) on rabbit splenic red pulp macrophages (RPMs), 39 female New Zealand White rabbits were divided into 10 groups: ovariectomized (OVX) and OVX/ IN at 0.1 and 5.0 mg/kg body weight (bw)/day; sham OVX (SOVX) and SOVX/IN at 0.1 and 5.0 mg/kg bw/day; OVX/25 mg E2 and OVX/25 mg E2/IN at 0.1 and 5.0 mg/kg bw/day; and intact control. Changes in RPM population in response to treatment were measured using a 0-4 histologic grade. Estradiol treatment resulted in increased RPM grade when compared to the OVX groups. Indomethacin addition lowered mean RPM grade in the SOVX/IN 5.0 group when compared to its E2 control group. Indomethacin administration had no significant effect on levels of prostaglandin E 2 in spleen, urine, or blood. Hematocrits were reduced in both OVX and OVX/E2 groups; this decrease was exacerbated by the high IN dose. In summary, the results from this study suggest that the effect of IN on E2-induced RPM activation may be mediated through a nonprostaglandin pathway. The observed hematocrit changes are possibly the result of direct action of IN and E2 on erythrocytes, resulting in their accelerated clearance from the circulation by splenic RPM.
489

Liquid Chromatography–Mass Spectrometry Applications for Quantification of Endogenous Sex Hormones

Gravitte, Amy, Archibald, Timothy, Cobble, Allison, Kennard, Benjamin, Brown, Stacy D. 01 January 2021 (has links)
Liquid chromatography, coupled with tandem mass spectrometry, presents a powerful tool for the quantification of the sex steroid hormones 17-β estradiol, progesterone and testosterone from biological matrices. The importance of accurate quantification with these hormones, even at endogenous levels, has evolved with our understanding of the role these regulators play in human development, fertility and disease risk and manifestation. Routine monitoring of these analytes can be accomplished by immunoassay techniques, which face limitations on specificity and sensitivity, or using gas chromatography–mass spectrometry. LC–MS/MS is growing in capability and acceptance for clinically relevant quantification of sex steroid hormones in biological matrices and is able to overcome many of the limitations of immunoassays. Analyte specificity has improved through the use of novel derivatizing agents, and sensitivity has been refined through the use of high-resolution chromatography and mass spectrometric technology. This review highlights these innovations, among others, in LC–MS/MS steroid hormone analysis captured in the literature over the last decade.
490

CYCLIC VOLTAMMETRIC DETERMINATION OF 17-α-ETHINYL ESTRADIOL ON DISPOSABLE SCREEN-PRINTED CARBON ELECTRODES

Qian, Zepeng 12 August 2019 (has links)
No description available.

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