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Fitoextração e Bioacessibilidade de As, Cd, Pb E Zn em solos contaminados por resíduos metalúrgicosSILVA, William Ramos da 29 July 2016 (has links)
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Previous issue date: 2016-07-29 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The generation of residues through mining is a potential risk of contamination of soil, water, plants and animals. For decades, the municipality of Santo Amaro da Purificação - BA has suffered the impacts caused by improper and inadequate release of thousands of tons of siderurgy slag contaminated mainly by Cd and Pb, and exposure of these contaminants to the population through the distribution of this material to landfills in squares, streets and homes. The city is now known for presenting the greatest human contamination by Pb in the world. In order to understand the impacts of residues in soil and the risk of human contamination from contaminated soil, this study investigated the phytoextraction by maize and castor as a technique for remediation of these soils and to evaluate the risk of human contamination by heavy metals added to the soil by waste. For this, an experiment was conducted in a greenhouse with the use of the two plant species and soil application of inducing agents Phytoextraction (NTA and citric acid). After the cultivation, they evaluated the levels of As, Cd, Pb and Zn in soil and plant to evaluate the potential remediation technique. Fractionation of metals in the soil and bioaccessibility tests to assess the risk of contamination were also performed. The application of chelating agents citric acid and NTA and increased absorption of heavy metals by maize and castor. Despite the removal of metals by application of citric acid is smaller, this is more suitable due to its higher degradability and assist in inhibiting the phytotoxicity of the metals. Corn showed better phytoextraction ability to As, Cd, Pb and Zn in the study. The castor, despite having high concentrations of metals translocated, presented accumulation in roots, can be used as phytoextabiletion plant and generating economic benefits for the production of non-edible vegetable oil. The presence of metal contaminants from the ground indiscriminately in the area of the former COBRAC presents a high risk of contamination of humans through exposure of metals. / A geração de resíduos através da mineração representa um risco potencial de contaminação do solo, recursos hídricos, plantas e animais. Durante décadas, o município de Santo Amaro da Purificação – BA tem sofrido os impactos causados pela liberação indevida e inadequada de milhares de toneladas de escória de siderurgia, contaminada principalmente por Cd e Pb, e pela exposição destes contaminantes à população através da distribuição desse material para aterros em praças, ruas e residências. A cidade hoje é conhecida por apresentar a maior contaminação humana por Pb no mundo. Com a intenção de entender os impactos causados pelos resíduos nos solos, bem como os riscos de contaminação humana por solo contaminado, o presente trabalho objetivou estudar a fitoextração por milho e mamona como uma técnica para remediação desses solos e avaliar o risco de contaminação humana pelos metais pesados adicionados ao solo pelos resíduos. Para isto, foi realizado um experimento em casa de vegetação com a utilização das duas espécies vegetais e aplicação ao solo de agentes indutores da fitoextração (ácido cítrico e NTA). Após o período de cultivo, foram avaliados os teores de As, Cd, Pb e Zn no solo e na planta para avaliar o potencial da técnica de remediação. Fracionamento dos metais no solo e testes de bioacessibilidade para avaliar o risco de contaminação foram também efetuados. A aplicação dos agentes quelantes ácido cítrico e NTA aumentou a absorção de metais pesados por milho e mamona. Apesar da remoção dos metais com aplicação de ácido cítrico ser menor, este é mais indicado por apresentar maior degradabilidade e auxiliar na inibição da fitotoxicidade dos metais. O milho apresentou melhor capacidade fitoextratora para As, Cd, Pb e Zn no solo em estudo. A mamona, apesar de não ter translocado concentrações altas dos metais, apresentou acúmulo nas raízes, podendo ser utilizada como planta fitoestabilizadora e geradora de benefícios econômicos pela produção de óleo vegetal não comestível. A presença de metais contaminantes do solo de forma indiscriminada na área da antiga COBRAC apresenta risco elevado de contaminação dos seres humanos através da exposição dos metais.
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Avaliação pré-clínica do análogo da neurotensina(8-13) radiomarcado com sup(99m)Tc: caracterização in vitro e in vivo / Preclinical evaluation of neurotensin(8-13) analog radiolabeled with 99mTc: in vitro and in vivo characterizationTEODORO, RODRIGO 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:27:46Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:05:01Z (GMT). No. of bitstreams: 0 / A radiomarcação de biomoléculas específicas com o tecnécio-99m 99mTc utilizando agentes quelantes bifuncionais é um campo em crescimento na Medicina Nuclear. Em especial, a classe de peptídeos regulatórios, como a Neurotensina, participa de processos fisiológicos essenciais no organismo, como o crescimento tumoral. O objetivo do presente trabalho foi o estudo comparativo da influência dos agentes quelantes bifuncionais 6-hidrazinonicotinamida (HYNIC) e S-acetil-mercaptoacetiltriglicina (MAG3), no comportamento in vitro e in vivo do análogo duplamente estabilizado da Neurotensina(8-13) radiomarcado com 99mTc, em células tumorais de mama da linhagem MDA-MB-231. Um elevado rendimento radioquímico (> 97%) e estabilidade frente aos agentes transquelantes foi observado para ambos análogos radiomarcados. Foram também obtidos comportamentos similares in vitro, no que diz respeito à porcentagem de ligação às proteinas plasmáticas (aproximadamente 22%), estabilidade metabólica, ligação aos receptores celulares (intervalo nM) e taxas de internalização/externalização para ambos radiocomplexos. A maior lipofilicidade encontrada para o análogo radiomarcado via MAG3 refletiu nas principais diferenças nos estudos de biodistribuição. A degradação do análogo radiomarcado via HYNIC nos estudos de estabilidade metabólica in vivo aos 90 min levou a menor retenção tumoral (0,44±0,02% DI/g), e consequentemente, às menores razões tumor/órgãos não-alvos (< 5%). Embora a superioridade do traçador marcado via MAG3 tenha sido comprovada no presente estudo, um redesenho estrutural objetivando contornar a alta captação no trato gastrointestinal deve ser realizada a fim de que sua potencial aplicabilidade não seja comprometida. / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Avaliação do efeito de diferentes agentes quelantes e desmineralizantes sobre a microdureza da dentina radicular / Evaluation of the effect of different chelating agents and demineralizing on the microhardness of root dentin.Josilaine Amaral Pimenta 17 October 2011 (has links)
O presente estudo teve como objetivo avaliar a ação das soluções de quitosana, EDTA e ácido cítrico sobre a microdureza da dentina radicular. Utilizaram-se 10 incisivos centrais superiores humanos, os quais tiveram suas coroas seccionadas transversalmente e desprezadas. As raízes foram incluídas em resina acrílica de rápida polimerização e o bloco formado raiz/resina adaptado a máquina de corte. Desprezou-se o primeiro corte transversal da porção cervical e dividiu-se o segundo, em quatro quadrantes. Cada quarto foi destinado à confecção do corpo de prova obtendo-se 4 espécimes para cada raiz, um para cada solução (n=10): G1- EDTA 15%; G2- ácido cítrico; G3- quitosana 0,2% e G4- controle. Os espécimes receberam 50 μL da solução por 5 minutos, sendo em seguida, lavados com água deionizada. Utilizou-se um microdurômetro (dureza Knoop) com carga de 10 g durante 15 segundos. Os resultados mostraram que todas as soluções avaliadas apresentaram capacidade de reduzir a microdureza da dentina radicular de forma semelhante entre si e estatisticamente diferente a do grupo controle (p<0,01). Concluiu-se as soluções de quitosana 0,2%, EDTA 15% e ácido cítrico 10% apresentam efeito semelhante na redução da microdureza dentinária. / The aim of this study was to evaluate the action of solutions: chitosan, EDTA and citric acid on the microhardness of the root dentin. There were used 10 human maxillary central incisors which ones had their crown cross-sectioned and discarded. The roots were embedded in acrylic resin of rapid polymerization and the block formed root/resin suitable by cutting machine. Neglecting the first cross-section of the cervical portion and the second was divided in four quadrants. Each quarter was destined to the confection of the specimen and it was got 4 specimen to each root, one for each solution (n=10): G1- EDTA 15%; G2- citric acid;G3- chitosan 0,2 % and G4- control. The specimen received 50 μL of the solution for 5 minutes, and following up they were washed by deionized water. It was used a microhardness (Knoop hardness) with a load of 10g during 15 seconds. The results showed that all the solutions evaluated presented a capacity to reduce the microhardness of the root dentin in a similar way between them, and statically differ from the control group (p<0,01). It was concluded that chitosan 0,2% EDTA 15% and the citric acid 10% presented a similar effect in the reduction of the dentin microhardness.
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The regulation of blue-green algae by iron availability and calcite precipitationMurphy, Thomas P.D. January 1987 (has links)
The primary objective of this research was to determine if changes in iron availability influence the periodicity of blue-green algal growth. A secondary goal was to resolve how iron availability was related to events such as calcite (calcium carbonate) precipitation and sediment nutrient release.
The biogeochemical regulation of blue-green algal succession was studied in three eutrophic hardwater lakes located upon the Thompson Plateau in south-central British Columbia. The experimental approaches included iri situ bottle and limnocorral experiments, sediment core analysis, monitoring of seasonal changes in water chemistry, and whole-lake manipulation by hypolimnetic aeration, or calcium hydroxide addition. Growth and primary production bioassays were used to evaluate iron availability. Microbial chelators were isolated from algal cultures and lake water, quantified by a chelation assay, and used to determine their in situ effects on algal productivity and bacterial heterotrophy.
Microbes were able to regulate the bioavailability of iron. Algal siderophore isolates were rapidly assimilated in lake water and they were highly specific for iron chelation. Moreover, chelator concentrations in Black Lake usually exceeded the dissolved iron concentration. Algae excreted chelators that could suppress growth of some other species of algae by 90%, enhance the primary production of some other algal species by 30%, or suppress the heterotrophic activity of bacteria by 14-98%.
The degree of iron limitation varied greatly during the summer. In Black Lake, iron limitation was more than ten-fold more intense in early summer than in late summer. Dense blooms of
blue-green algae occurred in Black Lake only after the iron
content of the lake increased from 20 to more than 100 ug/L. An
increase in iron concentration in the water column of the three
lakes was caused by a midsummer sediment release of iron.
Although sediment pyrite formation converted available iron
into refractory iron in both Chain and Frisken lakes, the degree
of iron limitation varied greatly among the lakes. Unlike in
Black Lake, the algae in Chain Lake were not limited by iron
availability. Phosphorus solubility was a good index of iron
availability. Black and Frisken lakes had too little iron for
iron phosphate to precipitate, but the higher iron concentration
in Chain Lake regulated phosphorus solubility. The differences
among lakes was primarily a function of external iron loading,
not sediment iron release. Chain Lake received 10³ more iron per m² than Frisken or Black lakes.
Carbonate equilibria integrated the microbial responses to iron enrichment. When iron availability was increased in the epilimnion of Black Lake, algal productivity was enhanced which resulted in an increase in pH and the coprecipitation of more calcite and phosphorus than in control treatments. The precipitation of calcite could sediment as much as 90% of the algae and 97% of the phosphorus from the epilimnion. The hypolimnia of the iron-enriched limnocorrals had the lowest pH and highest dissolution of precipitated phosphorus.
Three reactions, iron chelation, sediment iron release, and calcite precipitation, can regulate much of the periodicity of blue-green algal growth in hardwater lakes. / Science, Faculty of / Zoology, Department of / Graduate
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Effects of Chelating Agents on Texture of Lowfat Cheddar CheesePoveda, Mariela Fernanda 01 June 2013 (has links) (PDF)
Effects of two types of chelating agents on proteolysis and texture properties of low fat Cheddar cheese (LFC) were analyzed and compared to full fat Cheddar (FFC) control during ripening for 120 days at 8°C. We hypothesized that chelating agents would bind calcium ions from cheese matrix to give a softer curd due to a decrease of protein-protein interactions and simultaneously increasing moisture content. Cheese milk containing (0.59% fat) was divided into three lots (A, B & C). Sodium citrate (3Na) and disodium EDTA (EDTA) were added to A & B at the rate of (0.02% and 0.2% respectively. C served as control (LFC). Cheesemilk (88°F) was preacidified to pH 6.2 prior to setting using 34 ml chymosin/454 kg and starter culture addition. After cutting, curd was cooked to 96°F for 30 min and held for 10 min. After cooking, the curd was washed, salted, hooped and pressed. FFC was made on subsequence days from same batch of milk by the stirred curd method for Cheddar cheese, cheesemaking was replicated 5 times. Significant difference in moisture content (P˂0.05) was observed between FFC and LFC. Calcium content on the EDTA and 3Na was significantly reduced (P˂0.05) compared to FFC. No significant difference (P˃0.05) in hardness was observed between FFC and LFC at day 7 and 30. After day 30, significant differences (P
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Exploring Neoteric Solvent Extractants: Applications in the Removal of Sorbates From Solid Surfaces and Regeneration of Automotive Catalytic ConvertersSubramanian, Bhargavi 03 July 2007 (has links)
No description available.
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Cuprúria em pais de pacientes com doença de Wilson antes e depois da administração oral de d-penicilamina / Cupriuresis in parents of patients with Wilson disease before and after oral intake of d-penicillamineVieira, Jakeliny 31 May 2007 (has links)
A doença de Wilson (DW) é distúrbio da excreção biliar de cobre, de herança autossômica recessiva, devido a mutações no gene ATP7B. O cobre que não se liga à apoceruloplasmina circula no organismo ligado a aminoácidos, deposita-se principalmente no fígado e no cérebro e é excretado pelos rins. A cuprúria maior que 100ug/24h pode auxiliar no diagnóstico, embora cerca 20% dos pacientes com DW apresentem níveis anormais de cuprúria basal. A administração da d-penicilamina (DPA) pode promover, em crianças, valores maiores que 1.600ug/24h. A fim de se conhecer os níveis de cuprúria de possíveis indivíduos heterozigotos adultos, foram avaliados 25 pais e 25 mães de pacientes (média 61 anos em homens; 57 anos em mulheres) com diagnóstico de DW. Foram obtidos os níveis séricos de enzimas hepáticas, cobre e ceruloplasmina, e quantificada a cuprúria de 24h. A seguir, os indivíduos receberam DPA 1,0g por via oral dividido em duas tomadas, durante nova coleta de urina para dosagem de cuprúria de 24h. Esta análise foi realizada pelo método de espectrometria de absorção atômica eletrotérmica. Os níveis de enzimas hepáticas foram semelhantes nos dois grupos, exceto o nível médio de fosfatase alcalina que foi maior nas mulheres (H= 68,72 UI/L; M=81,68 UI/L). Os níveis de ceruloplasmina (H=21,72mg/dL; M=27,78mg/dL) e de cobre sérico (H=71,38 ?g/dl; M=88,0 ug/dl) foram maiores em mulheres do que em homens (p<0,001). Os níveis de cuprúria basal foram 22,43ug/24h (média) e 21,40ug/24h (mediana); e, após a DPA, de 523,54 ug/24h (média) e 511,5 ug/24h (mediana). A cuprúria média basal masculina foi de 26,19. ug/24h, enquanto a feminina foi de 18,28. ug/24h (p=0,005). Com o presente estudo, ficou definida possível faixa de variação da cuprúria antes e depois da administração de dpenicilamina em pais de portadores com doença de Wilson; que os pais apresentaram cupremia e níveis de ceruloplasmina menores e cuprúria basal maior do que as mães; que as faixas de variação de normalidade para os parâmetros ceruloplasmina, cobre sérico e urinário deveriam ser diferenciadas de acordo com o sexo. / Wilson disease is a biliary copper excretion disturbance, of recessive autossomic heritage, due to ATP7B gene mutations. The copper not bound to apoceruloplasmin circulates in the organism bound to amino acids and accumulates mainly in the liver and brain being excreted by the kidneys. Urinary copper higher than 100ug/24h can be useful in the diagnosis, but only about 20% of Wilson disease patients have abnormal basal levels. In this case, d-penicillamine (DPA) administration can lead, in children, to levels higher than 1.600ug/24h. Twenty five fathers and twenty five mothers of wilson disease patients (mean 61 years for male, and 57 years for female) were assessed in order to obtain urinary copper levels of probable heterozygote adults. Fasting liver enzymes, copper and ceruloplasmin serum levels were obtained along with 24h urinary copper excretion. After, patients got DPA 1.0g by oral route, twice a day, while collecting urine for 24h urinary copper excretion dosage. These analyses were performed by elethrotermic atomic absortion spectrometry method. Liver enzyme levels were similar in men and women but those of alkaline phosphatase were higher in women (M= 68.72 UI/L; F=81.68 UI/L). Serum ceruloplasmin (F=21.72mg/dl; F=27.78mg/dl) and copper (M=71.38 ug/dl; F=88.0 ug/dl) levels were higher in women than in men (p<0.001). Urinary copper levels before DPA were, 43ug/24h (mean) and 21.40 ug/24h (median); and, after DPA, 523.54 ug/24h (mean) and 511.5 ug/24h (median). Basal urinary copper levels in men were 26.9 ug/24h, and in women were 18.67 ug/24h (p=0.005). With the results of this study, we defined a possible range for urinary copper before and after oral intake of DPA in parents of Wilson disease patients. Furthermore, fathers had lower levels of serum copper and of ceruloplasmin, and greater levels of baseline cupriuresis than mothers; and finally the normal range for serum copper and ceruloplasmin, and urinary copper should be differentiated according to the gender.
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Reaction of Calcite and Dolomite with In-Situ Gelled Acids, Organic Acids, and Environmentally Friendly Chelating Agent (GLDA)Rabie, Ahmed 1978- 14 March 2013 (has links)
Well stimulation is the treatment remedy when oil/gas productivity decreases to unacceptable economical limits. Well stimulation can be carried out through either "Matrix Acidizing" or fracturing with both "Hydraulic Fracturing" and "Acid Fracturing" techniques. "Matrix Acidizing" and "Acid Fracturing" applications involve injecting an acid to react with the formation and dissolve some of the minerals present and recover or increase the permeability. The permeability enhancement is achieved by creating conductive channels "wormholes" in case of "Matrix Acidizing" or creating uneven etching pattern in case of "Acid Fracturing" treatments.
In both cases, and to design a treatment successfully, it is necessary to determine the distance that the live acid will be able to penetrate inside the formation, which in turn, determines the volume of the acid needed to carry out the treatment. This distance can be obtained through lab experiments, if formation cores are available, or estimated by modeling the treatment. The successful model will depend on several chemical and physical processes that take place including: the acid transport to the surface of the rock, the speed of the reaction of the acid with the rock, which is often referred to as "Reaction Rate", and the acid leak-off. The parameters describing these processes such as acid diffusion coefficient and reaction kinetics have to be determined experimentally to ensure accurate and reliable modeling.
Hydrochloric acid and simple organic acids such as acetic and citric acids have been used extensively for stimulation treatments. The diffusion and reaction kinetics of these acids, in a straight form, were investigated thoroughly in literature. However, solely these acids are used in a simple form in the field. Acid systems such as gelled, crosslinked gelled, surfactant-based, foam-based, or emulsified acids are used to either retard the reaction rate or to enhance acid diversion. Literature review shows that additional work is needed to understand the reaction and report the diffusion and kinetics of these systems with carbonate. In addition, a new chelating agent (GLDA) was recently introduced as a stand-alone stimulating fluid. The kinetics and the mass transfer properties of this acid were not studied before.
Therefore, the objective of this work is to study the reaction of different acid systems with calcite and dolomite and report the mass transport and kinetic data experimentally. Lactic acid, a chelating agent (GLDA), and in-situ gelled HCl-formic acids were investigated in this study. In some cases, rheology measurements and core flood experiments were conducted. The data were combined with the reaction study to understand the behavior of these acids and examine their efficiency if injected in the formation.
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Efeito do cádmio sobre a enzima d-aminolevulinato desidratase de pulmão de ratos in vitro: interação com agentes quelantes e antioxidantes / Effects of cadmium on d-aminolevulinate dehydratase from rat lung in vitro: interaction with chelating and antioxidant agentsLuchese, Cristiane 01 June 2007 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The exposure of human populations to a variety of heavy metals has been a public health concern. Cadmium is a non-essential elements due to its immense usage in various industrial applications, is an environmental contaminant with food and tobacco smoking. This toxic metal is more efficiently absorbed through the lungs than through the gastrointestinal tract. Therefore, the use of lung as a target tissue of cadmium exposure is of great importance because this heavy metal can be absorbed on suspended particles, entering the lung through the respiration. Thus, a possible therapy for metal intoxication is to remove the toxic metals from the bound functional bioligands. The present study was designed to evaluate the effect of cadmium on d-minolevulinate dehydratase (d-ALA-D) activity from rat lung in vitro. d-ALA-D activity, a toxicological parameter, has been reported as a target of cadmium in different tissues. The protective effect of monotherapies with dithiol chelating (meso-2,3-dimercaptosuccinic acid (DMSA) and 2,3-dimercaptopropane-1- sulfonic acid (DMPS)) or antioxidant agent (ascorbic acid, diphenyl diselenide, (PhSe)2, and Nacetylcysteine (NAC)) were also evaluated; as well as, the effect of a combined therapy (dithiol chelating x antioxidant agent) was studied. Moreover, to investigate the possible mechanism involved, we determined the effect of zinc chloride (ZnCl2) and dithiothreitol (DTT). The rat lung d-ALA-D activity was inhibited by low concentrations of cadmium, this inhibition occurred due the oxidation of SH groups of enzyme, and not by displacing zinc from the enzyme structure. The chelating agents were not effective in restoring enzyme activity inhibited by cadmium, and it presented an inhibitory effect per se. The possible mechanism involved in this inhibition was demonstrated. DTT restored the inhibition caused by both chelating agents, but ZnCl2 restored only the inhibitory effect of DMSA. This indicated that DMPS did not remove the zinc ions of the enzyme structure. This study also demonstrated that these chelating agents potentialized the d-ALA-D inhibition caused by cadmium. In this way, the study of possible mechanism verified that DTT restore the enzyme inhibition caused by cadmium/DMSA complex, but not by cadmium/DMPS complex. In contrast to DTT, ZnCl2 did not restore the enzyme activity inhibited by both complexes. In relation to antioxidants compounds, we can verify that none antioxidant utilized in this work was efficient in restoring the enzyme activity inhibited by cadmium. Some authors had demonstrated that the association of chelating and antioxidant agents is a good alternative in treatment of metal intoxication. In this way, we observed a combined effect of cadmium x DMPS x (PhSe)2 and cadmium x DMPS x NAC. However, this combined effect of cadmium x antioxidant x chelating did not observe when we utilized DMSA as chelating agent. In general, the results of this study indicate that cadmium inhibited the pulmonary d-ALA-D activity; and, the use oh chelating and antioxidant agents, alone or combined, 6 did not restore the enzyme activity, in some cases, potentialized the inhibition induced by cadmium. The principal mechanism involved in enzyme inhibition was the oxidation of SH groups. / A exposição das populações humanas a uma variedade de metais pesados é um problema de saúde pública. O cádmio é um elemento não essencial e devido ao seu imenso uso em diversas aplicações industriais, é um contaminante ambiental
através da comida e da fumaça do cigarro. Este metal tóxico é mais eficientemente absorvido através dos pulmões do que do trato gastrointestinal. Portanto, o uso dos pulmões como um tecido alvo do cádmio é de grande importância porque este metal pesado pode ser absorvido, entrando nos pulmões através da respiração. Uma terapia possível para a intoxicação por metais é remover os metais tóxicos ligados a
bioligantes funcionais. O presente estudo foi delineado para avaliar o efeito in vitro do cádmio na atividade da d-aminolevulinato desidratase (d-ALA-D) em pulmão de
rato. A atividade da d-ALA-D, um parâmetro toxicológico, tem sido reportada como alvo do cádmio em diferentes tecidos. Foram avaliados também o possível efeito protetor dos agentes quelantes ditiólicos (ácido 2,3-dimercapto-1-propanosulfônico (DMPS) e o ácido meso 2,3- dimercaptosuccínico (DMSA)) ou agentes antioxidantes
(ácido ascórbico, N-acetilcisteína (NAC) e o disseleneto de difenila (PhSe)2) isolados ou em combinação (agentes quelantes x antioxidantes). Além disso, para investigar
o possível mecanismo envolvido, nós determinamos o efeito restaurador do cloreto de zinco (ZnCl2) e do ditiotreitol (DTT) na d-ALA-D. A atividade da d-ALA-D de pulmão de rato foi inibida por baixas concentrações de cádmio, e esta inibição
ocorreu devido a oxidação dos grupos -SH da enzima, e não por remover os íons zinco da estrutura enzimática. Os agentes quelantes não foram efetivos em proteger a atividade da enzima inibida por cádmio, e apresentaram um efeito inibitório per se. O possível mecanismo envolvido nesta inibição foi demonstrado. O DTT restaurou a inibição causada por ambos agentes quelantes, mas o ZnCl2 restaurou somente o efeito inibitório do DMSA. Isto indica que o DMPS não remove os íons zinco da estrutura da enzima. Este estudo demonstrou também que estes agentes quelantes potencializam a inibição da d-ALA-D causada por cádmio. Neste sentido, o estudo do possível mecanismo verificou que o DTT restaura a inibição da enzima causada pelo complexo cádmio/DMSA, mas não pelo complexo cádmio/DMPS. Ao contrário do DTT, o ZnCl2 não restaura a atividade da enzima inibida por ambos complexos. Em relação aos compostos antioxidantes, nós podemos verificar que nenhum antioxidante utilizado neste trabalho foi eficiente em restaurar a atividade da enzima inibida por cádmio. Alguns autores têm demonstrado que a associação de agentes quelantes e antioxidantes é uma boa alternativa no tratamento das intoxicações por metais. Neste sentido, observou-se um efeito combinado de cádmio x DMPS x (PhSe)2 e cádmio x DMPS x NAC. Porém esse efeito combinado de cádmio x
antioxidantes x quelantes não foi observado quando se utilizou o DMSA como 4 agente quelante. De uma maneira geral, os resultados deste estudo indicam que o cádmio inibiu a atividade da d-ALA-D do tecido pulmonar; e ainda, o uso de agentes quelantes e antioxidantes, sozinhos ou combinados, não restauraram a atividade da enzima, sendo que em alguns casos, potencializaram a inibição induzida por cádmio. O mecanismo principal envolvido na inibição da enzima foi à oxidação dos grupos sulfidrílicos.
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Cuprúria em pais de pacientes com doença de Wilson antes e depois da administração oral de d-penicilamina / Cupriuresis in parents of patients with Wilson disease before and after oral intake of d-penicillamineJakeliny Vieira 31 May 2007 (has links)
A doença de Wilson (DW) é distúrbio da excreção biliar de cobre, de herança autossômica recessiva, devido a mutações no gene ATP7B. O cobre que não se liga à apoceruloplasmina circula no organismo ligado a aminoácidos, deposita-se principalmente no fígado e no cérebro e é excretado pelos rins. A cuprúria maior que 100ug/24h pode auxiliar no diagnóstico, embora cerca 20% dos pacientes com DW apresentem níveis anormais de cuprúria basal. A administração da d-penicilamina (DPA) pode promover, em crianças, valores maiores que 1.600ug/24h. A fim de se conhecer os níveis de cuprúria de possíveis indivíduos heterozigotos adultos, foram avaliados 25 pais e 25 mães de pacientes (média 61 anos em homens; 57 anos em mulheres) com diagnóstico de DW. Foram obtidos os níveis séricos de enzimas hepáticas, cobre e ceruloplasmina, e quantificada a cuprúria de 24h. A seguir, os indivíduos receberam DPA 1,0g por via oral dividido em duas tomadas, durante nova coleta de urina para dosagem de cuprúria de 24h. Esta análise foi realizada pelo método de espectrometria de absorção atômica eletrotérmica. Os níveis de enzimas hepáticas foram semelhantes nos dois grupos, exceto o nível médio de fosfatase alcalina que foi maior nas mulheres (H= 68,72 UI/L; M=81,68 UI/L). Os níveis de ceruloplasmina (H=21,72mg/dL; M=27,78mg/dL) e de cobre sérico (H=71,38 ?g/dl; M=88,0 ug/dl) foram maiores em mulheres do que em homens (p<0,001). Os níveis de cuprúria basal foram 22,43ug/24h (média) e 21,40ug/24h (mediana); e, após a DPA, de 523,54 ug/24h (média) e 511,5 ug/24h (mediana). A cuprúria média basal masculina foi de 26,19. ug/24h, enquanto a feminina foi de 18,28. ug/24h (p=0,005). Com o presente estudo, ficou definida possível faixa de variação da cuprúria antes e depois da administração de dpenicilamina em pais de portadores com doença de Wilson; que os pais apresentaram cupremia e níveis de ceruloplasmina menores e cuprúria basal maior do que as mães; que as faixas de variação de normalidade para os parâmetros ceruloplasmina, cobre sérico e urinário deveriam ser diferenciadas de acordo com o sexo. / Wilson disease is a biliary copper excretion disturbance, of recessive autossomic heritage, due to ATP7B gene mutations. The copper not bound to apoceruloplasmin circulates in the organism bound to amino acids and accumulates mainly in the liver and brain being excreted by the kidneys. Urinary copper higher than 100ug/24h can be useful in the diagnosis, but only about 20% of Wilson disease patients have abnormal basal levels. In this case, d-penicillamine (DPA) administration can lead, in children, to levels higher than 1.600ug/24h. Twenty five fathers and twenty five mothers of wilson disease patients (mean 61 years for male, and 57 years for female) were assessed in order to obtain urinary copper levels of probable heterozygote adults. Fasting liver enzymes, copper and ceruloplasmin serum levels were obtained along with 24h urinary copper excretion. After, patients got DPA 1.0g by oral route, twice a day, while collecting urine for 24h urinary copper excretion dosage. These analyses were performed by elethrotermic atomic absortion spectrometry method. Liver enzyme levels were similar in men and women but those of alkaline phosphatase were higher in women (M= 68.72 UI/L; F=81.68 UI/L). Serum ceruloplasmin (F=21.72mg/dl; F=27.78mg/dl) and copper (M=71.38 ug/dl; F=88.0 ug/dl) levels were higher in women than in men (p<0.001). Urinary copper levels before DPA were, 43ug/24h (mean) and 21.40 ug/24h (median); and, after DPA, 523.54 ug/24h (mean) and 511.5 ug/24h (median). Basal urinary copper levels in men were 26.9 ug/24h, and in women were 18.67 ug/24h (p=0.005). With the results of this study, we defined a possible range for urinary copper before and after oral intake of DPA in parents of Wilson disease patients. Furthermore, fathers had lower levels of serum copper and of ceruloplasmin, and greater levels of baseline cupriuresis than mothers; and finally the normal range for serum copper and ceruloplasmin, and urinary copper should be differentiated according to the gender.
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